| WELCOME to the anvilfire Guru's Den - V. 3.0 |
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THIS is a forum for questions and answers about blacksmithing and general metalworking. Ask the Guru any reasonable question and he or one of his helpers will answer your question, find someone that can, OR research the question for you. This is an archive of posts from June 16 - 24, 2006 on the Guru's Den |
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Gas Forge Ventilation: Darrell, This is a good question and I do not have an immediate answer. "Two burner" does not say much about the output of the forge as burners vary greatly. However, I suspect any ventilation blower larger than a bathroom ventilation fan is enough. Where you need to be careful is that it is rated for high temperatures like a commercial kitchen stove fan. |
| - guru - Friday, 06/16/06 08:07:02 EDT |
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Forges heating shop: A big part of this is radiant heading from the exterior of poorly designed forges. The normal 2" of Kaowool works but the exterior of the forge will still get quite hot after a few hours use and then the radiant heat is sufficient to heat objects a considerable distance away. The problem is extream with hard (ie dense)refractories. If you want a cool forge exterior then you need a hollow exterior shell with an air space that is vented along with exhust gases. The shell needs to have an air intake as well an exhust. For dead cool you need two shells. In many cases the shells can simply be a U shape that surrounds the bottom and sides with the top completely open to the vent above. In this case it is a heat shield rather than a shell. A double heat shield is much more efficient at keeping the exterior cool than added insulation. Note however that hard refractory forges need a light weight refractory cover to reduce the temperature to when the heat shields do not over heat. At the knife makers meet I went to a couple weeks ago all the forges had air curtains to control dragon's breath. These were simply a nozzel (like a wide thin vacuume cleaner nozzel) set about 4" away from the forge opening blowing air UP. These had a small blower to make them work OR as in the case of one forge the forge blower supplied air to the burner AND the air curtain. The air curtain would assure that the exhust goes up a reasonble size hood as well thus reducing CO and CO2 in the shop. You could stand inches away from the opening of these forges and not get burned. This is a very good reason to abandon the so called "simplicity" of finicky atmospheric burners and just go to blown forges (which always run hotter). |
| - guru - Saturday, 06/17/06 08:15:00 EDT |
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Mike B I have a 24" turbine ventalator in the roof just above my gasser. This turbine moves a tremendous amount of air in a slight breeze. With the gasser running, the updraft powers the turbine, and spins it even faster. Think Sirkosky helicopter like sounds amd air movement :) |
| ptree - Saturday, 06/17/06 08:19:02 EDT |
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I'm off for about 36 hours. Have some family business to attend to. Be back Sunday afternoon. |
| - guru - Saturday, 06/17/06 10:29:47 EDT |
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Propane forges just give off humongous quantities of toxic nasties that linger, no way around it. Mine is totally out of doors and nonetheless exhaust hangs around. So (gasp!) do the fumes from anything that might be on the junk steel I am recycling into objets d'haha art when I cook it. When it was inside the shop, even with front and rear doors and roof hatches wide open, same: bad headaches. Soooo, I just built me a whompus 10-foot diameter tin tipi out of corrugated roofing that encloses the monster totally except for access ports fore and aft. My (hopeful) theory is, the thermal convection currents will carry the nasties skyward, where they will dissipate before contributing noticeably to global warming and general planetary (and my) degredation. Stay tuned. Watch for a blinding blue flash in the mountains north of Santa Fe. |
| Miles Undercut - Saturday, 06/17/06 11:19:19 EDT |
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Ken, Pie are square? Pie are round; cornbread are square. Couldn't help m'self. |
| Frank Turley - Saturday, 06/17/06 11:23:01 EDT |
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Miles, Headaches are symptom of carbon monoxide poisioning. CO is a sign of a rich mixture( too much fuel, not enough air) and poor fuel economy. It is deadly and cumulitive in your system. I've been there, done that...and so it is a pet peeve of mine. Get a Nighthawk (tm) DIGITAL alarm for your shop. It takes 6 days to rid your body of exposure to CO. The digital read out can be used to tune your forge. Take action before you get your next saftey meeting from Paw-Paw. |
| Habu - Saturday, 06/17/06 12:31:28 EDT |
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What is a 250# little giant worth? It is an older one peice, in great condition, new flat dies and newish moter. I paid $4995 for it a long time ago and I just want to know if it has appreciated in value over the years. Can you help with a ball park figure or have you seen some of these sold recently and how much did they go for? |
| - Colby - Saturday, 06/17/06 13:50:57 EDT |
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What is a 250# little giant worth? It is an older one peice, in great condition, new flat dies and newish moter. I paid $4995 for it a long time ago and I just want to know if it has appreciated in value over the years. Can you help with a ball park figure or have you seen some of these sold recently and how much did they go for? |
| - Colby - Saturday, 06/17/06 13:51:12 EDT |
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What is a 250# little giant worth? It is an older one peice, in great condition, new flat dies and newish moter. I paid $4995 for it a long time ago and I just want to know if it has appreciated in value over the years. Can you help with a ball park figure or have you seen some of these sold recently and how much did they go for? |
| Colby - Saturday, 06/17/06 13:52:02 EDT |
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Zinc question: I just used a spray-can of cold galvanizing compound to coat some recent work, and had a fair amount of overspray on the ground (on the path from car to house). Do I need to be concerned about the zinc? I would think not, but thought I should ask. |
| Paymeister - Saturday, 06/17/06 13:55:03 EDT |
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Coal Fire Woes: I've been having some difficulting managing my coal fire and I'm not sure what I'm doing wrong. I can't seem to get the fire big enough so that it is hot above the level of the top of my firepot so I can't heat anything but the ends of my stock. I've got a little brake drum forge set in a table that is about 10" in diameter with a 2" tuyere (2" pipe with a 1/4" plate with 1/4" holes drilled in it for air) with a plundered range-hood fan for air, the drum is only about 2 1/2" deep so the fire stays really quite small. From my reading online (can't remember if it was here or somewhere linked to from here) that it is ideal to have 4" - 4 1/2" of fire beneath the iron so that most of the oxygen is burned up. So that implies that your fire should be substantially higher than mine. Do you have any recommendations? Is my tuyere too small? Is my blower too weak? Do I need to build my fire in a special way? Your help is greatly appreciated! |
| Condredge - Saturday, 06/17/06 14:10:56 EDT |
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Forge size: pi x r^2 xh is the vol of a right cylinder. Guessing that you have 2" of wool and that 15" is the dia gives pi x 6.5^2 x 20 roughly 2500 cu ins. Reil type burners are rated for about 300 cu ins so you would need 8 burners! Which ever calculation is right, Mike, Ken or Adam, they all agree that your burn chamber is way oversized for the burners A couple of other things: Jet size is usually #58. I use a #60 at 7000' and the burner has to be derated some. The cross section is much too square - typically the cylinder is 2 or 2 times longer than wide. This helps to contain the swirling gas longer and also reduces the amount of radiant heat loss. At forging temps the main heat loss is radiant (light) (Stefans Law 4th power effect yata yata". Any window that sees directly into the forges core is a MAJOR heat loss and you have a huge window. You can greatly reduce this kind of loss by placing a refractory barrier in front of the mouth but perhaps an inch away to allow gas flow and access with the work. The main thing is that to minimize the direct line of site paths for the radiant heat to escape. The barrier will heat up and reflect a lot of light back into the forge Unless you want to weld up enormous damascus billets, size is NOT important - temperature is the most important thing. I use a 4" diameter gas forge that runs at welding heat and I can make a gate with it! Think about the way a coal fire is used. For venting I open th garage doors and run a big fan "Frank couldnt help himself" This is a leetel hard to believe - where pie and cornbread are concerned, Frank will find a way to help himself and come back for seconds! ;) |
| adam - Saturday, 06/17/06 14:15:21 EDT |
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Clarification: "the cross section of the BURN CHAMBER is much too square." |
| adam - Saturday, 06/17/06 14:17:30 EDT |
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Before my neighbors objected , I used ran a forge with a 2" tuyere and the fire was 6" to 8" in dia. 1/4" holes sounds waaaay too small I suspect you are strangling the air flow, drill them out to 3/8". Also pile up your coal so the you have enough depth over the firepot. A sheet metal table around the fire pot helps with this. |
| adam - Saturday, 06/17/06 14:38:20 EDT |
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Adam, thanks for your advice on this! I'll try drilling the holes bigger. I do have a sheet metal table so I can pile it high, but it just doesn't burn higher... Hopefully my neighbours don't object as well! I'm going to switch to coke once I use up my coal which should be pretty soon. Then the smoke won't be yellow and nasty |
| Condredge - Saturday, 06/17/06 14:48:37 EDT |
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Habu-- many thanks! I appreciate the advice. Actually, though, carbon monoxide is an inevitable by-product of just about any fuel burn, no? What I am considering here, for the Fourth of July, slow forging periods, and the Santa Fe Fiesta, is capping the top, holding off on the ignition while letting the propane build up under the tin tipi, then letting a spark go. Why should that Virgin Airways guy get a lock on the first manned space center? Get your reservations in early. |
| Miles Undercut - Saturday, 06/17/06 16:37:43 EDT |
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AFAIK zinc is a concern when it gets heated or ground and one inhales or swallows the results. I wouldnt worry unless thats yo8ur favorite spot for torch cutting - (shouldnt cut over concrete anyways) |
| adam - Saturday, 06/17/06 17:39:55 EDT |
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Does anybody know where to get antique looking bolts like square headed ones? I would like some original looking bolts to attatch the railing I am building for a house. |
| - Ty Rankin - Saturday, 06/17/06 18:23:38 EDT |
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where can I find reproduction bolts to install railing on a staircase. would like to find square headed bolts and not galvanized. |
| - Ty Rankin - Saturday, 06/17/06 18:30:59 EDT |
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HYey, i have been forging on a large peice of railroad track on its side, so theres alot of mass under it, and its less loud than when its flat , but its still very loud, is that as loud as an anvil would be generally? i keep gettting complaints from my parents because its so loud, thanks |
| Dylan - Saturday, 06/17/06 18:54:06 EDT |
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Mine would be the first COMMERCIAL manned space center in NM. MUST start reading these posts. Before I post. |
| Miles Undercut - Saturday, 06/17/06 19:05:03 EDT |
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Frank, good one! I was laughing for a while before I was capable if asking this question thanks to your "pie are round" comment.-Grin! My question is: I'm getting more work done on the chainsaw bike I mention a few months ago, but now I need to press a bike wheel hub with a welded on pulley tightly against the rear tire. The scrap I have around here is not good enough to use for this, and I was wondering; Where would I be able to get some cheap scrap pipe, and would I be able to use anything else? I plane on welding this to the bike frame, but it can't be too heavy. Any help would be appreciated! ---Rob |
| - Rob - Saturday, 06/17/06 19:15:49 EDT |
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Sorry, I didn't mention what the pipe was needed for: I was planning on drilling it out so I could fit a fair sized bolt through it to hold the hub against the wheel. |
| - Rob - Saturday, 06/17/06 19:17:37 EDT |
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I've been practicing forge welding mild steel. I heat to red, wire brush, flux, heat to weld temp, flux, re-heat then hit it over the anvil. I'm doing fagot welds to build up a multi-layer billot. I've tried other joints, but haven't got the co-ordination of hands/tongs/heat/hammer yet.... Anyway, I weld a billot. I grind the edges & can't see any seam. I cut it with a hack saw & can't see any seam. However, if I put the cold billot in the vice & drive a cold chisel into the first weld (since it still has the remainder of the length protruding), I can break it open. Once a split is started, I can just grab the length in my hands then pull & continue that split so as to pull of the first layer. This doesn't seem good. Any suggestions? |
| andrew - Saturday, 06/17/06 20:00:04 EDT |
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Adam, My math was the same as yours -- I just used 18" for the length (allowing for 1" wool at each end) and divided by 1728 to get cubic feet. Just for the record, 2" of kaowool would reduce the *radius* by 2" (from 7.5 to 5.5). Using that and 16" for the length, gives 1520 cubic inches. Still a lot more than 600. Ptree, I'll keep your suggestion in mind. At this point, I'm trying to avoid going through the roof -- I think most of the neighbors haven't figured out where the noise is coming from yet! I do have a gable end fan, and now a furnace blower that blows outside air directly on me. |
| Mike B - Saturday, 06/17/06 20:08:23 EDT |
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Ty: Marks Nuts & Bolts here in the Phoenix area carries square headed bolts and screws. Their number is 623 939-9312. |
| dief - Saturday, 06/17/06 22:36:24 EDT |
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Miles: >Actually, though, carbon monoxide is an inevitable by-product of just about any fuel burn, no?< Not quite. a complete burn of a fuel that has enough Oxygen will give carbon dioxide or CO2, Carbon monoxide or CO happens in a burn with out enough oxygen to complete the burn. This is what happens in a reduction enviroment that produces a little or no scale in your forge. If you are getting scale your forge is set to an oxidizing mixture with excess oxygen in the enviroment and the output will be almost pure CO2. CO attaches to your red blood cell like oxygen, but it will not detach from the cell when it returns to your lungs. Your blood accumulates the CO and oxygen cannot be carried by your blood. Death, brain damage, heart, kidney, and liver problems are all attributed to short and long term exposure to CO. Coal and charcoal also produce CO, but the coal smoke is often enough to make people open some doors and windows before the level of CO becomes a threat. You can't see or smell CO , Death can happen within moments at levels above 700 parts per million and within hours at levels of 80ppm. the Nighthawk alarm has an algorithum that takes into account the level and length of exposure and has a buzzer that will wake up the dead. Mine sets above and near the forge and a quick glance will tell me if my forge is running right and if levels are rising. I have had times when my forge produced levels above 999ppm in less than 15min in my garage, with out the alarm I would not have known it. My unit is 6 years old and cost $60, a lot less than the trip in the black limo. |
| Habu - Saturday, 06/17/06 22:38:16 EDT |
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Condredge: Your 1/4" holes might be fine if there are enough of them. Think in terms of having about 1-1/2 to 2 square inches of draft area. That means you'd need about 30 1/4" holes. The 2" pipe would be just fine if you just welded a couple of 3/8" sqare bars across it to keep the coal from falling through. That jwould net you about 1.5 in˛ blast area. The biggest problem I would think you're having is not enough air from that range hood blower. Most of those things, unless you're talking a commercial kitchen hood, use wimply little blowers that only move about 60-80 cfm - with NO back pressure. A blow drier will give you a better air source. Disconnect the heating element and use some flex duct to hook it to the forge from far enough away to keep it from getting melted. |
| vicopper - Saturday, 06/17/06 22:44:23 EDT |
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Colby: I think it was the economist Adam Smith who said, "The value of a thing is what that thing will bring." Prettyy much applies to your 250 LG. If somebody wants one badly enough, and you're selling, then you get a profit. But if someone else is selling a Nazel 3-B for 5 grand, guess which one I'd buy? |
| vicopper - Saturday, 06/17/06 22:57:26 EDT |
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Ty Rankin: Uhhhh, maybe I'm not tracking here but, why wouldn't a blacksmith just forge the hex heads to square? Only takes a minute or two each, max. |
| vicopper - Saturday, 06/17/06 23:01:22 EDT |
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Condredge: The work should be IN the burning coal, not on top of the fire like so many artists have drawn it. Some firebricks around the firepot can increase it's effective depth. Enlarging the holes untill there is only a thin web between them should solve the air problem IF THE FAN CAN MAKE ENOUGH PRESSURE. Try other blowers [hair dryer etc.] if it still doesn't work. |
| Dave Boyer - Saturday, 06/17/06 23:12:26 EDT |
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Andrew: Are you grinding the mild steel to a bare, shiny, scale-free finish before you try to weld it? Other than sufficient heat, I think the most critical requirements for a successful forge weld are "fit and finish." Clean and shiny, and closely fitting to minimize intrusion of dirt and oxygen. When you grind the surfaces for welding, make them just barely convex, maybe five or ten thousandths of an inch rise in the middle of a 1" wide bar, say. This will cause the weld to stick in the center first, then squeeze the flux and dross out the sides as it closes down, keeping the surfaces clean. When you have the fit, finish, flux and heat right, you can get the weld to stick with a rather light blow. I favor a fairly heavy hammer, but farily gentle blows at first. This gives the requisite mass to get the blow to the center of the stack, but you don't have to hit is so hard that you blast the near-molten surface metal clean out of the joint. Once you have it "stuck", take a second welding heat and work it with harder blows. |
| vicopper - Saturday, 06/17/06 23:15:52 EDT |
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Hanu-- Again, many thanks. I appreciate your making the effort to straighten me out on this and warn me of the dangers. I thought cars and propane water heaters and propane furnaces and all those other engineered devices just inescapably produced carbon monoxide as a matter of the nature of combustion. Have you told Detroit about this? |
| Miles Undercut - Sunday, 06/18/06 00:01:50 EDT |
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Habu-- Oops, sorry for the name misspelling! Getting late here. Many thanks again. You really should, if you have not already, alert the furnace companies, water heater manufacturers, automakers, fire marshals, building inspectors about your findings. Sounds to me as if it would save a lot of lives and make the world a vastly better place if combustion devices were only required to be properly tuned, tested and certified. Over and out here in the foothills of the Rockies. |
| Miles Undercut - Sunday, 06/18/06 00:17:52 EDT |
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Miles: Here in the east We have auto emmision inspection, CO being one of the things they check for, and it is supposed to be close to 0%. I was having carb troubble with My van one time, running it in the garage with the door open, and the alarm in the house above went off. Another time My 50's vintage engine drive welder was being used for standby power, in spite of having the exhaust piped outside the meter still showed an elevated CO reading in the house.I had the same problem with a portable generator running on deck on My sailboat one time. Modern cars and apliances in proper condition should make little or no CO, all bets are off with older equiptment. |
| Dave Boyer - Sunday, 06/18/06 00:33:48 EDT |
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VIcopper: I noticed the same problem as Andrew, the weld looked pretty good with respect to contaminants. I would like to know how well forge weld holds up to the pry apart test when one of You experienced guys does it. I used 1/4x1 1/4 stock and welded the last 3/4" together. As I pried it open the stock bent as the weld parted. This type of test puts almoast infinant stress on a line across the weld which just keeps moving as it fails rather than loading the entire welded area at one time. |
| Dave Boyer - Sunday, 06/18/06 00:48:50 EDT |
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Dave Boyer, With respect to "mild steel" (A-36), you kind of never quite know for sure what you're going to get. The chemistry for A-36 is arbitrary, and so the forge weld results are, too. The only real spec that applies to A-36 is the 36 kpsi tensile strength. So some of it welds just fine for me, with pretty close to 100% strength, and other pieces just barely stick when I do everything right. Kind of a crap shoot. Sulfur content, possibly. I'm no metallurgist, but Quenchcrack or one of the other metallurgists would probably have some good input. If you use 1018, then the chemistry is pretty dependable and consistent, and the welds will come out pretty consistent and pretty strong; maybe 85+% or so of parent stock strength. Higher carbon straight alloys like 1045 or 1095 achieve essentially 100% strength bonds. (If not, laminated steel blades wouldn't hold up well, no?) But the list of possible "contaminants" in A-36 reads like the period chart, and all sorts of weird stuff can happen. Theoretically, with sufficiently clean and tightly fitted steel working in a vacuum, you can weld at room temp with sufficient pressure. Solid state diffusion bonding. The pressures required get kinda exciting though, I think. But with some of the crud in A-36, I'll bet even that won't work dependably. Nasty stuff. |
| vicopper - Sunday, 06/18/06 01:13:24 EDT |
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The test you used does put essentially infinite stress on the weld, Dave. The weakest point in the steel will fail, and that is going to be the weld; even if it is 99.999% as strong as the parent stock, it is still the weakest point in the strain zone. If the stock is bending before parting, then you're pretty darn close to a full strength weld, I'd say. |
| vicopper - Sunday, 06/18/06 01:16:11 EDT |
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I have a couple of questions first i'm planning on buying a halflinger horse for riding and I need to know what to look for when looking at the shoes of the horse to determan if the horse needs new shoes,and how often do they need to have their shoes changed? |
| denise - Sunday, 06/18/06 08:06:02 EDT |
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CO. ANY combustion process has the potential to emit Carbon monoxide. If for any reason the fuel to air ratio gets off the perfect, then CO is formed instead of the ideal CO2 and H2O. As the fuel portion of the mixture increases (Rich) the portion of CO increases. Working as a safety guy in a 250,000 square foot factory, I have to check the CO levels twice daily as we run propane fork truck, and the factory is airconditioned. We have a 25% fresh air content in the make up air, and it is amazing how fast one out of tune truck can change the CO content at breathing level from 1 to 2 parts per million to 12 or 15 PPM. A simple re-tune or sometimes plugs ETC returns the engine to emitting something like 3 or 4PPM. I have seen reports in the safety trades that suggest increased fatique and headaches can occur at levels as low as 10 PPM. As CO is very hard for the body to expell, if you are eposed daily, you can have cummulative build-up of CO at levels well below the deadly in a short term exposure. Please consider the ventilation, tuning and other issues when running any unvented fuel burning appliance. |
| ptree - Sunday, 06/18/06 09:03:15 EDT |
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CO exposure: I owened and opperated an auto emission test station in Colorado for 7 years and tested up to 90 cars a day, 6 days a week in a 18' x 25' bay. Most modern cars would test at levels below the detectable by my equipment. one in 20 would not pass the test, at 1.5% of tail pipe gasses, one in 50 would exceed the 10% limit of my equipment. Note that is a % of total gas emissions not parts per million. My building was a drive thrugh facility that had garage doors at both ends that were open whenever testing was going on. I took care to avoid exposure by standing on the up wind side of the shop durring testing and watching the readings on the Nighthawk alarm read out durring the test because my equipment tested in a blind mode. Still, I went home many a night with splitting headaches, dizzyness, slurred speach and dull thinking. After 15 years away from exposure, I still have memory problems with things like names for people and objects, and this effects my speech patterns. Heart and lung dammage are also a concern. My inability to spell however was not affected.(grin) If you don't think the government is aware of the exposure to CO compare the engine configuration of a 1957 chevy with a modern car, most of what you see is due to emission controls and fuel economy. Tunning of other combustion devices is still a good idea, tho most use a lean mixture to assure a compete burn of the gas in an open air enviroment this leads to most of the fuel being fully burned. If you look at the burners of most applinces you will note a choke to adjust air fuel mixture. Enclosed burns as in an auto cylinder or a closed forge allow the gasses to burn the available Oxygen durring the burn cycle. A Rich mixture(reducing flame)= more CO. If you have Dragons breath from your forge, this is fuel that is burning in the open air out side your forge. If you do not get scale on your steel in your forge then you have a reducing enviroment that is probably producing some CO. Paw-paw and I discussed this at length just before his death and he told me he was going to put an alarm in his shop, I don't know if he ever did. Habu, owner of Grumpy's Emissions |
| habu - Sunday, 06/18/06 10:29:47 EDT |
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My Pinto has a Hooker header on it along with a staight piped no cat exhaust. The smog pump is removed as well as any fuel return lines that would have normally gone to the cat and carb. These modifications allow the car to acheive better horsepower and mileage. It also increases the CO and hydrocarbon output. Because it is an older car, I don't just start her up and drive off, I have to warm it up for a minute or two. Fortunately I do not have a garage to fill up with CO. I do worry about CO killing my pets, I have exotic birds and reptiles in my house and when the CO alarm goes off I stop work immediately and turn on exhaust fans (I have gotten into the habit of turning the fans on BEFORE I forge now). |
| - Nippulini - Sunday, 06/18/06 10:56:57 EDT |
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Some thoughts on a first gas forge: THINK OUTSIDE THE BOX! It seems that about once a month with dependable regularity, someone, having built his first gas forge needs help troubleshooting it. Nothingwrongwiththat. It’s what we’re her for. Nearly always, the problem is that forge wont get hot enough and usually, it turns out that the combustion chamber is very large, somewhere north of 1000 cu ins. IMO this is a mistake. It’s a natural mistake. The thinking goes something like this:- “Got to make that nice window grill for my lady and it’s going have a couple of 10” scrolls. Once I start bending the work it’s not going to fit inside that inky dinky little forge that Ron Reil made. Gonna need at least a 10” dia chamber. This departs from a known working design - generally not a smart idea with a first effort but people do it anyway because a gas forge seems like such a simple affair; Just a hot little oven running on propane. Its not simple, its quite tricky and unless you have experience you are likely to miss a lot of important subtleties and the forge wont work well. Running a combustion chamber at 2000F (welding heat) is NOTHING like running the same chamber at, say, 1500F red heat. It’s a different game. Especially if the forge is designed to run with an opening in the front, like Ron’s Mini Forge. Such a design does not simply scale up – there has to be some careful thought. I see a lot of gas forges like this and mostly they run cold and the owner is working his steel much too cold. In the early stages of forging, the steel should be close to welding heat – perhaps even a spark or two. Not only is this much easier to forge but the steel moves differently – very differently. So whether one plans to weld or not the forge should reliably attain welding heat. Another confusion is about the way gas forges are to be used. Gas forges can be roughly categorized into three types. 1. To feed a power hammer. In this case one may want to work with 8” of hot steel and have several pieces going at the same time. These forges are usually the “big oven” design with a hinged door that closes on the work. 2, 4 or even 8 burners are not unusual. Such forges don’t generally have to run at welding heat because a power hammer doesn’t require it. But if its just you and your little 3# crosspein you don’t want 8” of hot steel. You wont be able to use all that heat and it will be hard to control. 2. Blade making. This often involves welding up Damascus billets – repetitive BIG welds. These forges tend to be the “little oven” design. The whole work is put in the chamber and a door closes after it. The forge runs at welding heat. 3.YOUR FORGE This is to be a general purpose forge. Some big some small – perhaps its your first forge and you don’t really know yet what you are going to be doing. You need something versatile. You don’t need a big oven – think outside the box! You need a small hot forge. The internal dimensions should be something like 5” dia x 10” long .Like Ron’s Mini Forge. Most of your work will not fit inside, instead you will lay it ACROSS THE MOUTH of the forge and heat up a short section at a time. You should have no trouble getting the work to orange heat and if you need hotter, stack some fire brick up in front of the forge so that it heats up and reflects the heat back. If you want to weld, Then you can make a little roof too. Essentially you use the forge as a burner and you set up a temporary heating chamber at the mouth of the forge. I prefer to make some blocks and walls out of kaowool coated with a skim of some refractory (thankyou Guru) since these heat up much faster, but plain ole yeller firebrick works fine too. You will likely find that you want a little “porch” made of firebrick in front of your forge. This technique does take a bit of practice to get things working smoothly and you are likely to drop some very hot firebrick on the floor – but its all part of the fun. A final point once you have some experience, you will find that gas forges are indeed easy to make and you might make a couple more for special work. Also, its no big deal to set up a temporary forge of kaowool and firebrick and just transfer your existing burner to it. |
| adam - Sunday, 06/18/06 11:01:43 EDT |
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Many thanks for the illuminating info, Habu, Dave Boyer, and ptree. I am going out and get myself a canary for my smithy as soon as the pet shop opens! |
| Miles Undercut - Sunday, 06/18/06 11:04:43 EDT |
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After thought: I have been working with small gas forges for over 10 years. The , umm, "wisdom" above was won by making every stupid mistake (several times). Yep, my very first forge was a "modified" Reil Mini Forge and it ran about hot enough to make muffins. Ron was *very* patient with me when I emailed him to ask "Why wont it get hot????" |
| adam - Sunday, 06/18/06 11:13:58 EDT |
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CO detectors: I would suggest getting a detector with a readout. Once the alarm goes off (or the canary goes toes-up), there's nothing left to do but shut down, ventilate, and then wait for things to settle. By watching my detector, once I see the numbers climbing, I know to get the ventilation going and I can therefore keep going. That's mainly in the winter, though. In the summer I've got the ventilation going just to cool off. And for me, my shop is in a two-car garage. I replaced the overhead doors with swingouts and have an openable window in each door half. All I need for ventilation is a cheap pedestal fan, where I lengthened the pedestal to reach the door window. I exhaust out the window on the far right door and open the window on the far left. The CO goes down to 0 minutes after I start that up. |
| - Marc - Sunday, 06/18/06 11:34:12 EDT |
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Hi Mike T. In regards to your question about wedge type scarfs vs. cupped scarfs, it looks like your query was a result of reading the opinion of the beautifuliron.com web site on tong rein welds. Is this correct? Cupped scarfs are not always appropriate for welds, for example in welding billets. The web site cautions against using wedge shaped scarfs for attaching tong reins. It also says that only beginners use borax for flux, and such welds always fail. I don't think that this is quite correct. I have seen some demos featuring well-known non-beginner smiths using borax to produce very servicable welds. I also saw a demo of a weld done with no flux; it failed immediately upon further forging, but the smith (an expert, not a beginner) just cranked the heat up a little more and rewelded the joint as part of the forging. The final piece ended up just fine, and I think it ended up selling at the evening auction. There was a pair of tongs on sale at a blacksmith's auction. The weld on the reins was not scarfed at all. In fact, the two bars were lapped diagonally mis-aligned. Really ugly, with a big gap. But the tongs were well used, and appeared to have held up. People examining the tongs were flexing them hard expecting the weld to show weakness, but the weld contact surface must have been long enough so it was strong. As for the "cupped scarf", why don't you follow the link on the web page to the free book. That tells how to make a cupped scarf. It is done by setting down over a rounded edge of the anvil. |
| EricC - Sunday, 06/18/06 12:01:27 EDT |
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I am thinking of putting some 1" square solid bar stock directly into a concrete step for a railing newel post. I am curious what is the minimum size hole I should make in order to put mortar in the gap and have it be secure. I was thinking of using "cemente blanco." I learned about it from some Mexican guys who were installing a gate into stone columns with it. I used it to install into stone and it was interesting material, it hardened so hard it almost had a "ring" to it. Second question is , what is it and how does it differ from common cement? I wonder if I can rely on even ordinary cement/sand mortar mix to be strong enough to allow me to use, say, a 2" hole for the 1" bar. |
| brian kennedy - Sunday, 06/18/06 18:51:25 EDT |
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I've got an idea for using those little 16 oz. propane bottles but I need to know a safe way to cut them(empty, of course). Can you offer a suggestion? Thank You. Steve |
| Steve Stransky - Sunday, 06/18/06 20:07:59 EDT |
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Guru, I'm looking for some rr spikes and can't seem to find any that i caould use in my shop. Can you recommend any places that I can get them from? |
| Mike K. - Sunday, 06/18/06 20:31:36 EDT |
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My post vises ae mounted on stands made from 1.5 inch square tubing. In order to increase the stability, I want to fill all areas of the tubing and cap the ends. My question is, what would give me the most weight-filling them with old lead wheel weights or sand? |
| Brian C - Sunday, 06/18/06 20:35:02 EDT |
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Small propane bottle. I just puncture it with an awl, I like to do it right where it says "Do not puncture" When it stops hissing I slice it open with an abrasive disk. |
| adam - Sunday, 06/18/06 20:51:48 EDT |
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Lead is much denser than steel or sand but it might depend on how they stack inside the pipe. You might could pack it with wheel wts AND some sand to fill in the voids and soak up any ringing. Ideal would be to heat the pipe to about 600F and make the wts melt but that could be a lot of work. |
| adam - Sunday, 06/18/06 20:55:03 EDT |
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Brake Drum Forge: 1/4" holes for grate???????? Look at my plans. Do you see and plate with holes??? Plates with holes, floor drain covers, tubes with holes (neo-tribal). . all are a waste of time and effort. Forges need a large opening with a gentle BLAST of air. . . not little tiny whistling holes. . . This is a FORGE not a flute. . . I start with aproximnately a 2" hole and leave it wide OPEN. If my coal is too small I put a SINGLE piece of 1/2" stock across the hole. WORKS. Doesn't clog. |
| - guru - Sunday, 06/18/06 21:07:46 EDT |
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Gunsmithing: The National Muzzle Loading Rifle Association has a series of books called the Journal of Historical Arms and Technologies. This series covers a lot of what you need to know and includes a lot of information on how lock parts were forged along with other information that would be of inrterest to many on this site. They can be found at NMLRA.org Mike |
| M. Yazel - Sunday, 06/18/06 21:26:50 EDT |
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BIG RANT! Filling things with lead: Unless it is an absolute need for some VERY sound engineering reasons you have no business melting and pouring lead! Its toxic and you can easily find the EPA labeling your shop and all the soil around it a hazardous waste dump from spilling just a pouind or so spilled. DOn't do it. I know people still fill treadle hammer and junk yard hammer heads with lead. . WELL, IT IS STUPID!!!! Don't do it. Steel is just a little less dense than lead. Just build with steel to start. If you want to pour liquid metal fill use zinc. . . .(91% as dense as steel). Yeah its toxic overheated but the zinc dust on your clothes will not make YOUR CHILDREN RETARDED. If you overheat lead it will not make you a little sick, it will KILL YOU. Before using lead DO THE DENSITY VOLUME CALCS and figure out how little more volume it takes to use steel or zinc. If you cannot figure it out then perhaps you've been exposed to too much lead already. Is this a RANT? Yes this is a yelling screaming RANT! You do not even have to use lead for radiation shielding! Steel works just as well provided there is an equivalent mass between you and the raditation source. I KNOW. I've built millions of dollars worth of radiation shielding and stood behind it. NO RADIATION! Steel works. Its 1/10th the cost of lead, you can weld it easily and it is self supporting in huge pieces which lead is NOT. Lead is bad stuff. Use it only as a last resort. There are more ways to use other things than you can count. |
| - guru - Sunday, 06/18/06 21:27:34 EDT |
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A vise stand does little good using dead weight unless you can make it in the 500 pound range or greater. With torque, even 1,000 pound benches move. . . To make it entirely immovable and light weight just attach a thin plate to the base that you stand on. You can not move the object you are standing on unless you try REAL HARD using inertia. Using torque, impossible. See our FAQ on blacksmiths leg vises and see the stand with the round base. Note also that in THIS CASE the plate is too flexible and the vise springs. Diagonals will cure. |
| - guru - Sunday, 06/18/06 21:30:48 EDT |
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Denise, Every horse owner has a different opinion on shoes for their horses. Unless I'm moving cows in the hill's I leave mine barefoot but have them trimmed or reshod every 7 to 8 weeks. About shoeing in general, wear on the toe is the determining factor on the life of the shoes. However, before you invest in a horse you should line up all your ducks in a row....one of those ducks is your farrier. Ask your vet clinic to recommend one and then let him guide you in your shoeing needs. Don't forget to have the horse vet'ed before you buy it and if possible, as the farrier familiar with the horse if he knows of any problems or pricy corrections that should be done on the hooves. Buying a horse is a crap shoot, hedge your bets with all the professional help you can get !! |
| Thumper - Sunday, 06/18/06 21:34:48 EDT |
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Small Propane bottles: Steve, As Adam noted, you punch a hole in them. Many have a little reinforced circle ready to punch. Note that you MUST empty the bottle first (attach a valve and vent). Shake it to see if you can feel fluid move. When punching do it away from open flames, wear safety glasses and gloves would not hurt. Once they have a hole in them they are safe to dispose of. |
| - guru - Sunday, 06/18/06 21:38:27 EDT |
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Anchoring in Masonary: Brian, First, I much prefer epoxy for a bunch of reasons. One brand of the special non-shrinking concrete made for this purpose in the US is called Rockite. When using cement you want sufficient space all around the part to have continous and strong piece of concrete. Typical holes are 2" and up. Many masonary contractors have the hollow core diamond drills for this purpose. I'm not sure what "cemente blanco" is. I've used very rich mixtures of portland cement and fine sand. But using a commercial miz designed for the purpose is better. |
| - guru - Sunday, 06/18/06 21:46:30 EDT |
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Forge Weld Strength in Mild Steel: Where the problem lies is that most iron/steel heated in gas or coal forges ends up significantly decarburized on the surface. These decarburized surfaces are what your weld is made of. In the case of wrought iron which has no carbon to start, the weld is as strong as the base metal. In any steel reducing carbon reduces strength and thus the weld if made from decarburized steel will always be weaker than the surrounding metal. |
| - guru - Sunday, 06/18/06 21:51:45 EDT |
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Square Head Screws: Kayne and Son, blacksmithsdepot.com , carry them. Square headed lag bolts are no longer made except by special order by the thousands several years in advance. If you MUST have them then make them. RR-Spikes: You can buy new ones from McMaster-Carr mcmaster.com. Used ones come from rail roads. 250# Little Giant Value: As noted above, they are worth what someone is willing to pay for them. However, the interesting thing about Little Giants is that due to portability, power needed, cost of moving, room to set up. . and DEMAND they ALL sell fro roughly the same from 25 pounds UP. In the case of the 250 you can add its potential scrap value (which is not insignificant). Many smiths have no clue how wonderful a BIG hammer is and are scarred to death of them. So there is less demand. There is also the problem of power. A 250# LG needs a full 7.5HP or 10 HP motor. Many places in the country can not run that big a motor (I currently cannot). SO, even though I would love to have a big hammer I cannot currently run one. However, I DO have a gasoline powered air compressor to run a big air hammer. . . That is why I traded off my 250 Little Giant. . . Location is also important. If the people that want your hammer are on the other side of the country they shipping will be a significant addition to their price. These things tend to be worth more the farther away from the industrialized North East and Rust Belt. So if you are in Ohio the hammer is worth much less than in California or Utah. |
| - guru - Sunday, 06/18/06 22:11:39 EDT |
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Cemente blanco: Down here, it is a white portland cement made in Puerto Rico, with a high lime content, used for repairs to historic buildings that were originally built using white lime mortar. It is actually NOT correct, and will cause problems due to incompatible transient moisture absorption and also incompatible strength. It's actually too good a product to be compatible with the old white lime mortar. Rockite; basically a portland cement/gypsum blend that expands upon hardening and has fairly high crush strength. The lack of aggregate makes it not so hot for shear/tensile strength of course, but then you don't use it in shear. Good for resistance to withdrawal of fasteners, provided that said fasteners are corrugated or otherwise textured to resist slipping. |
| vicopper - Sunday, 06/18/06 22:18:13 EDT |
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Lead: While I am in no way endorsing using lead where it is not needed, it is 45% more dense than steel and 58% more dense than cast iron. Usless in treaddle or power hammers, but it makes a BIG difference in the verticle center of gravity in a sailboat keel, for instance. If You melt lead You need to take the necessairy precautions. |
| Dave Boyer - Sunday, 06/18/06 22:44:52 EDT |
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Rob, I can't help you, unless you live in Santa Fe, I go to Capital Scrap Iron or Airport Auto Acres for my needs. Condredge, Build a deep fire. Build up a volcanic cone around the fire. Wet the coal if it's small enough so you can pack it around the fire center steeper than the angle of repose. Drilled holes are the worst type of tuyere. They clog up the fastest, and furthermore, they remind me of an ole timey bathtub drain. A simple hole about 5/8" x 1˝" works much better. As Boyer sez, put your work in the heart of the fire, and cover with about 2" of coke. Brian Kennedy, I have used Rockite brand anchor cement over the years, and am satisfied with it. It is probably similar to Cemente Blanco. Look for it with your search engines. Mike K., I have RR spikes for sale. Will ship. Forge Weld Strength. Besides the decarbuization problem, there is grain growth along the line of the weld, because you've been in the "incipient burning range". Furthermore, in a coal forge situation, you get what the metallurgists call, "slag inclusions" (fly ash; dirt). The grain growth can be restored somewhat by annealing. I've said this before on this forum about forge welds. "I don't care how weak it is, as long as it's strong enough". I like to flux at a brighter than a red heat, and I flux only once. When laminating, hammering from one end to the other with flat, overlapping blows is helpful in squeezing the "grunge" out in one direction only. |
| Frank Turley - Sunday, 06/18/06 22:47:45 EDT |
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http://www.joslynmfg.com/prodGrp.aspx?grp=54 Here is just one supplier of squarehead lags |
| - Sven - Sunday, 06/18/06 23:41:03 EDT |
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VIcopper, Jock, Frank - Weld strength: Yes the peel apart test is probably the easiest way to load to failure, which is pretty much what I planned to do to see if the whole surface "took". Understandably that type of joint is unsuited for structural aplications due to the strap not being stiff enough to resist bending and transfer the load to the entire weld. I asked Jonathan Nedbore the demonstrater at R&T last weekend [John Larson says He is the best forge welder He has seen] about the weld failing, He didn't seem surprised and commented about it being a poor type of joint in that loading. I guess the lesson is that joint geometry is equally if not more important in forge welding as with any other type. |
| Dave Boyer - Monday, 06/19/06 02:30:08 EDT |
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I called the power plant at the Arkansas Power and Light company and asked if I could purchase some coal from them. The head man said he would make arrangements for me to get some, but he said it was soft coal mined from the Powder River Basin in Wyoming. He said you could step on a piece of it and it would crush. Would this be OK to use or will charcoal be better ? |
| Mike Thompson - Monday, 06/19/06 03:01:09 EDT |
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Mike, Top grade blacksmiths coal is bituminous AKA "soft" coal. However, what you want is high BTU, low ash, low sulfur, soft coal. Coal, comes in INFINITE variety. Power plants do not use "trash" coal but they use some pretty bad stuff sometimes. Get a bucket full and test it before getting more. I know a couple smiths with multi ton mounds of useless coal cluttering their yard. |
| - guru - Monday, 06/19/06 07:41:35 EDT |
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Mike, PRB coal should be very good coal. Currently it is the fuel of choice for many power plants in the US due to it's low ash and sulfur contents. A typical fuel analysis for PRB is as follows: Carbon: 67.9% Hydrogen: 4.8% Oxygen: 10.4% Nitrogen: 1.5% Sulfur: 1% Ash: 4.1% Moisture: 10.3% (as received) Volatile Matter: 40.2% Fixed Carbon: 45.4% HHV: 13,900 Btu/lb This particular analysis is a composite of seams 7,7 1/2,9, and 15 from the Sweetwater coal field in Wyoming. |
| Steven Galonska - Monday, 06/19/06 08:16:43 EDT |
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Lead Density and applications: Yep a whopping 45% more dense. So the following is true: Lead vs. Steel 1 x 1 x 1 = 1 x 1 x 1.45 1 x 1 x 1 = 1.063 x 1.063 x 1.283 1 x 1 x 1 = 1.132 x 1.132 x 1.132 So a cube of steel equal in weight to a cube of lead is only 13% larger in each dimension. Any designer worth his salt can easily put the same mass in nearly the same space using the two different materials in most cases. Boat keels often have a torpedo shaped mass on the bottom to lower the mass cg as much as possible. If this is made 20% longer and 20% larger in diameter in steel it will equal lead. In fact, in steel the exterior fiberglass can be reduced to a minimum just to protect against rust and the total diameter increase reduced to about 10%. The only time this would b critical is in a world class racing boat. Otherwise it is an acceptable change. IF the designer only changed the length of the keel by 45% then the cross sectional flow reisitance would be no different then with lead. For radiation shielding we were using cast material which can have voids so we often doubled the thickness of our ductile iron shielding. But the most important thing was that we could build shields 4" and 6" thick that were not only self supporting but could support other equipment weighing tons. An equivalent lead shield would sag under its own weight. AND needing to be cast a heavy supporting shell was needed in any case. The costs of lead compared to steel were enormous plus the heavy welded shell and the casting. . . Due to space limitations we built only one lead lined shield device. This allowed a man to work for hours inside a relatively small pump bore in an environment that would otherwise kill him in a few minutes. Out of dozens of shielding devices this was the only place we used lead. A lot of thick concrete is used as radiation shielding. In the 1960's they used a special high density mineral as agregate to increase the average density. Today they have wised up and realized that steel shot and pellets is the way to go. Soft Lead Mallets: Used to be a common item but today we have those wonderful softer plastic dead blow hammers. If they don't work skip to brass. . . Plumbing (from the latin plumbum for lead) solder is now mostly tin with a bit of other things to make it harder (silver was used for a while). Its a little more expensive but there is no lead. . . Will people centuries from now wonder why the root of the word plumbing is "lead" and there is no lead in plumbing? |
| - guru - Monday, 06/19/06 09:06:44 EDT |
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Propane bottles: I put a center punch to the bottle, then drill a hole in it UNDER WATER! I don't know if this is adding any extra safety, but I worry about an errant spark from the drill bit. I use empty bottles for micro forges and lawn ornaments (they make nice little air pigs). What do you have planned for your empties? |
| - Nippulini - Monday, 06/19/06 10:04:53 EDT |
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Guru mentioned attaching a light weight base plate to stand on to secure your vise, I put one on my anvil stand and totally eliminated the "wander" I used to have on my 100# anvil no matter whether using the heel, center, or horn!! Just make sure it's thin enough sheet that you don't trip over it. Sure beats tying the stand down permanenty in case you want to change your shop around later. |
| Thumper - Monday, 06/19/06 11:07:21 EDT |
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Hey, Jonathan Nedbor was mentioned above; he's an old "Turley Grad". However, I can't claim his fame and skill. He did it on his own. LEAD reminded me of two metal related expressions. I wonder how old they are. My old Okie friend, when speaking of something easily done, would say, "Why that's a lead pipe cinch." My mom, always genteel, would say, "That's not worth a tinker's dam." |
| Frank Turley - Monday, 06/19/06 11:35:09 EDT |
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Re; Rocktite Thanks for the tips. I will reread the label on the Rocktite. It seems to me that when I read the label on one of those expanding pour-it-in products it said that it was not recommended for applications that could get wet. Which kind of made sense because it's behavior was similar to plaster in the fast set-up characteristic. I thought people were using it pretty often for outside. applications. I'll check into it at the hardware store again, maybe I'm confusing it with another product. The thing I don't like about the epoxy products I have used is the waste products that go in the landfill, they look pretty toxic, and tend to be expensive. Some kind of cement seems a little more benign. |
| brian kennedy - Monday, 06/19/06 11:41:28 EDT |
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Brian, I think they mean under water. . . We had a crew use Rockite on a water turbine installation and it dissappeared. . . but in applications like setting sign posts in boulders, railing on steps and such it works well. I prefer using epoxy because it is absolutely positive anchorage in all types of materials. But the two tube dispensers and the consumable mixing tubes are not inexpensive. I bought the gun for a big commercial job (bolt anchors in a river bed for a bridge) that paid for it. |
| - guru - Monday, 06/19/06 11:59:12 EDT |
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Reference Rocktite, etc. Just a couple of weeks ago, I installed some chain link fence for my son. We were going to use the usual quikcrete until I noticed a big pile of sacks that were a product designed specifically for setting posts in a mixture designed to be used underground. The main thing about it was that it was 100% fly ash. It hardens in 30 minutes to a peculiar yellowish color and is very, very hard. It only cost a $1 more per bag than quikcrete. Might be worth checking into. I bought it at Sutherlands. |
| Brummbaer - Monday, 06/19/06 12:22:14 EDT |
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I AGREE lead is not good. I DID SPEND TIME I N THE NUC SERVICE. LEAD WAS ONLY A SECONDARY ITEM OR WANT. AT LEAST ON MY BOAT. |
| Ralph - Monday, 06/19/06 13:52:09 EDT |
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Lead pipe: I recall reading where the Romans used lead water pipes and there is some speculation part of the decline of the Roman Empire may have been due to lead poisoning. Brian Kennedy: Were it me I'd weld on some nuts or such onto the post end before setting it in concrete. Logic is they would help anchor the post better than smooth sides. I have used both rebar and smooth steel bars for electric fence posts in the past. The rebar is MUCH harder to pull out than the smooth posts. If you put rebar down through gravely-soil you pretty well have to dig them out. |
| - Ken Scharabok - Monday, 06/19/06 13:56:56 EDT |
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Hello all, looking for a bit of help, if you would. Just bought a 100# Murrey power hammer, works great, with one small exception. When I let off of the foot ring the center clutch stays stightly engaged. The slide mech. for the clutch tilts slightly. Any thoughts on how to correct this issue would be greatly appreciated. Thanks for your time folks. |
| - VLAD - Monday, 06/19/06 13:57:48 EDT |
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Steven, Thanks for the PRB coal analysis. I will try it. Thanks Mike |
| Mike Thompson - Monday, 06/19/06 14:32:07 EDT |
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Frank, I think "tinker's dam" is at least as old as my late grandaddy; he was born in 1888. It was the little asbestos dam that tinkers used to patch holes in pots, pans and tubs. |
| Ron Childers - Monday, 06/19/06 14:41:17 EDT |
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Good luck Mike. Hopefully you can get some at a decent price. Powder River Basin (PRB) coal is very much in demand now and as such is much more expesive than other types of coal. However, if you're buying small quantities it shouldn't be too bad. |
| Steven Galonska - Monday, 06/19/06 14:49:57 EDT |
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"Murrey" Powerhammer VLAD, The Murray Hammers, were previously the Moloch hammer and designed by the Mayer Brothers of Little Giant. Although the hammers are very similar they were built in seperate factories from different plans and patterns. I am not clear on which part you are speaking off. The sliding clutch pulley on these slides on the same bearing that they rotate on. Repair requires disassembly, machining out the old babitt, pouring new babbitt and machining the new babbitt to fit the shaft. Unlike most babbitted bearings this one requires machining to fit. This assures the tapered clutch surface runs true to the shaft. Note that these clutches require a lot of lubrication or the bearings AND the clutch friction surface. Thick grease can cause the clutch to drag. On Little Giants this bearing is lubricated with grease which spins out onto the clutch and often thickens the oil required to make the clutch perform correctly. Thus the grease must be flushed with oil. The book, The Little Gant Powerhammer by Kern has some information about the repair of these clutches. Be sure the treadle return spring is lifting the treadle completely and fully disengaging the clutch. |
| - guru - Monday, 06/19/06 15:47:51 EDT |
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We cut the bottom of a water tank off for the bottom of our coal forge. Have everything almost done. I was thinking of cutting the top of the tank off for a hood. The top and bottom are rounded. How much should the hood be cut off ? Also, where should the flue be placed for proper draw ? |
| Mike Thompson - Monday, 06/19/06 16:27:14 EDT |
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Mike, See our plans page for side draft hoods. You should have enough material from the tank you make a cut here, another there, a weld here, a weld there and put together a side draft type hood nearly over the forge. The important thing is the 10" and UP stack (12" recommended) and for the intake to be just to the side of the fire and no bigger than 12 x 12". |
| - guru - Monday, 06/19/06 16:57:19 EDT |
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When I need to add mass to a tubular structure, such as my Junk Yard Hammer, I have used steel shot. I have always been lucky to work at a shop that used shot blast machines when I needed some, and as it is dumped to a landfill when underize from use free. On my hammer, I added about 7 gallons. Then as I ran the hammer, and the shot packed in, i ended up adding about another gallon. With the humidity around here, that shot is now a solid mass, and the hollow hammer column gives a dull thud when struck with a hammer. |
| ptree - Monday, 06/19/06 17:55:00 EDT |
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Ken, on the subject of Romans and lead pipe, I read that the only reason that the lead pipe was usable was that the lead was quickly covered with lime deposits making it relatively safe. They didn’t know anything about that at the time however. |
| Mike H - Monday, 06/19/06 18:48:18 EDT |
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Actually in "world class" racing boats (Like America's cup contenders) they now prefer depleated uranium! The difference is more than you calculated because you are using the weight in the atmosphere not under water. Oak may seem heavy but it weighs nothing under water (actually a little less than nothing as it's boyant). |
| - grant - Monday, 06/19/06 21:02:27 EDT |
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Grant, Yep, there is a difference. In fact, density as specific gravity is generaly measured in relationship to water, water being 1, other things being relative to water. Bouancy (subtracting the "1" does make things much lighter relatively speaking) and changes the ratio slightly. Specific gravity steel = 7.85 lead = 11.35 ratio = 1.45 steel in water = 6.85 g/cm3 lead in water = 10.35 g/cm3 ratio in water 1.51 You want heavy. . . uranium = 18.95 gold = 19.32 tungsten = 19.3 The cost of tungsten ($30 to $50/lb) is far less than depleted uranium and LOT less than gold. . . |
| - guru - Monday, 06/19/06 21:44:47 EDT |
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Steel may not be the most dense but for practical purposes it is cheaper and much safer than lead. There are no good reasons to use it in for mass in machinery. Bulk tungsten is sold in pellets and powder. |
| - guru - Monday, 06/19/06 21:48:28 EDT |
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While we're on the subject: Concrete is heavy and aluminum is light, right? Concrete weighs LESS than aluminum! We just tend to use aluminum in a lot smaller sections. Fun stuff. |
| - grant - Monday, 06/19/06 22:20:49 EDT |
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Ballast Keels: Iron & steel are only used for reasons of economy. Tungsten is not used for reasons of economy & class rules. Ballast bulbs have a terrible lift to drag ratio BECAUSE THEY PROVIDE NO LIFT.If configured as an endplate to the foil the total L/D ratio isn't as bad. Thickness of fiberglas keel shells is a function of how long You want the boat to be able to survive while grounded in a rockpile or reef, not a function of the strength of what is inside it. Most modern sailboats are externally ballasted, the keel is bolted onto a stub extending from the hull. As this is a narrow mounting surface the less hight of a dense ballast keel makes for a more reliable and overall stronger junction. While You may fiddle the numbers to make the difference between lead and iron look insignificant, You aren't going to convince the naval arcitects, or fool Mother Nature. Grant:Thwere are no racing class rules that presently allow ballast of a greater density than lead, the Russions did use depleted uraniun in one boat once I believe. The hot setup in racing boats now is a keel that swings to the side to provide much greater righting arm WITHOUT the boat heeling. |
| Dave Boyer - Monday, 06/19/06 22:54:47 EDT |
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I have a question on proper hammer usage. I have found that if I do a full extended arm swing (approx 150-170 degree extention), for 20 min or so, I have mild tennis elbow for several days. I've practiced and changed my form to a more direct strike using my shoulder more and not extending my arm past about 120 degrees. My farrier has complained of shoulder soreness using this method but I'm fine. Seems like I have the same power and more control this way and I haven't noticed any time difference in working mild steel. Is it going to effect me over time? And if so, what changes should I make? |
| Thumper - Monday, 06/19/06 23:50:24 EDT |
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I am not licensed to practice in your county (or any county for that matter) but Tennis Elbow is muy serious affliction, requiring surgery to repair, similar to Little League Elbow, in that snap stress on a tendon has literally pulled a protuberance of bone, that little knob, off the inside of the elbow joint. If you had tennis elbow you would not be hammering at all I suspect. There is bursitis, in which you inflame the bursa of your shoulder. There is tendinitis in which you inflame a tendon. You can stress the brachio radialis muscle of your forearm by striking long and hard on something that up too high, such as in the leg vise. Then there is a plain old garden variety charlie horse, which sets in the next day from hammering too hard for too long too soon. Answer to all: stop hammering when you first start feeling fatigued until your arm gets in shape. My broinlaw the Alexander Method practitioner sez to swing the hammer on the anvil mainly using the power of the shoulder, swinging in close to the body. |
| Miles Undercut - Tuesday, 06/20/06 00:03:11 EDT |
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Thanks Brummbaer, I'll be on the lookout. Thanks Ken, I will weld a little something on there in case my 92-year-old customer starts feeling frisky enough to attempt a dead lift on the railing. Thanks Guru for the story about the turbine--whoops! |
| brian kennedy - Tuesday, 06/20/06 01:37:42 EDT |
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Here is a story from today: I was using an oxy-acetylene torch to heat something. Meanwhile I had a Lincoln Ranger portable welder-generator supplying power to a Lincoln 170T small 220v mig welder and a smaller Lincoln 110v mig and a plasma cutter. I was alternately tacking with the 220 mig while my helper did the same with the 110 mig. Once in a while I cut something with the plasma cutter after turning on a 110v compressor plugged into the same generator. My oxy-acetlene set is barely working, I'm having trouble with the valves on the torch, the regulators don't read, I'm guessing at the pressures. So I am trying to nurse this torch along, it's my last semi-working one, I'm trying to light it, it is popping, I am concentrating on adjusting the gases, and BANG! There is bright fire near the back of the little 220 mig and loud sounds of blowing air. I first think something has happened to the plasma cutter because the bright flame is bluish almost like some kind of electrical fire. The back of the 220 welder has some flames and the cord and the gas line are melting. I turn off the generator and it continues and I realize that the oxy-acetylene hose is burned in half and blowing fire. I had run the hose right past the back of the welder where the exhaust fan vent is and that is where the hose blew(it was a pretty new hose.) I ran in and turned the valve off. I was caught by surprise on that play. Does anyone understand what happened? I've heard of blowback in a torch, but the hoses burnt right next to the welding machine. Did warm air coming out of the vent onto the hoses heat them hot enough to trigger this explosion? |
| brian kennedy - Tuesday, 06/20/06 02:09:22 EDT |
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Brian K: As acetylene pressure aproaches 30 PSIG it can ignite by itself, without oxygen. In the tank it is disolved in acetone, otherwise it would detonate when they fill the tank. The popping at the torch could have caused a momentary increase in the line pressure and caused detonation in the hose if their are no or malfunctioning flashback arestors or check valves. Without functioning guages coupled with a problem regulator the pressure could get close to the detonation point and You would have no way to know. Acetylene regulators SHOULD not supply more than 15 PSIG, which is the safe limit of pressure. Possibly the pressure was close to the detonation point and when the elevated pressure wave from the popping got to the warmer part of the hose it went off. Flashback from the torch is a posibility allso, do You have flashback arestors or at least check valves on the torch? Too much pressure makes the torch hard to adjust, at proper pressure the valves should be open a full turn [this doesn't aply to oxygen on a cutting torch]to reduce sensitivety. Acetylene is an inherently unstable fuel, using compromised equiptment leads to the situation You just experienced, or worse. Mapp is a safer high performance fuel, and propane even safer and adequate for most purposes, and more economical as well. Some new gear is what You need, You might not be as luckey next time. |
| Dave Boyer - Tuesday, 06/20/06 03:18:12 EDT |
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Dave Boyer: I was remembering a RTW boat of a number of years ago. I think that exact swink keel was described in "Common Sense of Yacht Design" by Herreshoff in what, 1946? |
| - grant - Tuesday, 06/20/06 03:41:23 EDT |
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When I demonstrate forging I advise there are really three hammer swings. The shoulder for doing heavy work, the elbow for moderate and wrist for light. It is also important to keep the elbow into the body rather than flailing away from the side. |
| Ken Scharabok - Tuesday, 06/20/06 04:55:25 EDT |
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Thumper, No one is going to be able to describe verbally how to swing a hammer, and no matter how good your form, there is something called repetitive stress syndrome, over time. There are many factors involved, the weight of the hammer, for example. I use 2.5#; I used to use 3# for much of my work. There is the hand grip. I use the tennis player admonition. When first learning, the coach says, "Shake hands with the racket." When you do, your thumb wraps around the handle, unless you're one of those dead fish hand shakers. That is the grip I teach for smithing. There is a good drawing of it in Schwarzkopf's book. Frank Wilson, the neurologist, wrote a book called "The Hand". He talks about homo saps (pun intended) ability to hold something like a hammer handle with the fingers pointing back diagonally toward the ham of the thumb and wrist/forearm. This allows you hold a haft pretty much parallel to your forearm. The lesser primates can't do that. They have a smaller thumb in a different location, and their fingers wrap around an object at right angles to its length. There is an arc to the swing. I watched Edward Martin of Closeburn, Scotland, working. He says that there is a sort of pull-back "look/feeling" when you contact the metal, which may be more apparent than real. Many beginners PUSH the hammer forward on contacting the metal mistakenly thinking that they are "really drawing it out". I tell them that all they are only "ice skating". In the English book, "The Blacksmith's Craft", there is a statement, "Don't use drawing blows; hit the metal fair and square." By the bye, in the year 2000, Edward Martin was called to London to receive one of three gold medals presented by The Worshipful Company of Blacksmiths in the last 100 years. The medal states that he is a "Supreme Master Blacksmith". Another factor; how close are you to the anvil? Miles mentioned the Alexander Method. There is also the Feldenkreis method, and others. The practicioners of these methods can analyze your movements at the anvil and provide corrective bodily measures. Two martial arts which put heavy emphasis on grounding, relaxation and deep breathing, are tai chi and aikido. Some of this methodology is valuable, if it can be brought into the studio. That is a big "IF". Nowadays, we talk about ergonomics. Ergonomics is a very broad field which addresses the subject of how we posture ourselves to the artifacts we have made. If you're going to be at the anvil a lot, it pays to bring consicousness and good habits to the work. You must be your own critic in many instances. You can catch yourself holding the hammer too tightly or with your thumb on top, holding your breath against your work, gritting your teeth, etc. Uri Hofi has a method of canting the hammer handle in the hand when drawing metal. The edge of the hammer face acts a little like a fuller, creating friction heat. However, I don't think he and I are at odds when talking generically about the arc of the swing. A swing is a swing is a swing. |
| Frank Turley - Tuesday, 06/20/06 10:04:32 EDT |
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Tinker's dam goes back to the renaissance at least and is probably medieval---they used a dab of clay for the dam. Isn't theat term used in Shakespeare somewhere? Thomas |
| Thomas P - Tuesday, 06/20/06 10:32:26 EDT |
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Ok, I suspect tendinits rather than tennis elbow (whew) and in reference to how I stand, it's close to and over the anvil, head slightly in front of where the hammer strikes, I've had the pleasure of the hammer whistling by my ear at the speed of light after a mis-strike. Elbow close to my side and hammer held like a, well, hammer, all fingers wrapped, no leading with the thumb up the shaft, a habit I broke a couple of years ago. Sounds like I also have the three methods of striking down pat. The extended swing I used to use probably had me striking off center and snapping with the elbow. The height of contact is the culprit I suspect this last time. I was using my guiotine(sp) fuller to neck down 1/2 to 1/4 and used it so long and hard, I cracked the weld holding the striking face loose, add to that it's 6# higher than the anvil face. Sounds like I've got the problem whooped and shouldn't be looking at shoulder problems down the road, my farriers 77, maybe I should try to teach that old dog some new tricks if he'll let me. Thanks all for your input. |
| Thumper - Tuesday, 06/20/06 10:54:55 EDT |
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I have a some what of a problem when I make knife blades and I hope some one can point me in the right direction. Some of the blades I make seem to "chip" when I put the final edge on them when using a hand held knife sharpener (I am sure you have seen these they kinda look like a plasic "D" with a groove to draw the blade threw). Only some blades do this, same metal same quenching prosses and they are all taken back in the same oven at the same temp. about 1 of 3 blades will do this. The chips are small but it leaves a rather jagged edge that will not cut well and looks even worse. Any suggestions? |
| Jed Depew - Tuesday, 06/20/06 11:05:47 EDT |
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Jed, Lots can go wrong and you have not provided enough ingormation. Are you forging the blades or using stock removal? Alloy? New or used material? I would guess you are going for too hard an edge but that is just a guess. Then there is burning or decarburizing the steel and not grinding enough off. |
| - guru - Tuesday, 06/20/06 12:42:53 EDT |
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Has anyone forged 12L11 or 12L14 steel and had any issues with the lead in it? I am looking at doing some tomahawk heads based on originals forged from gun barrels and the barrel scrap I have is from 12L material. I have spent my life casting lead balls and have friends casting 3000 lbs a year to sell without probelms but forging is a lot hotter than casting temps. I know the lead content in 12L material is quite small but thought it must vaporise in the forging process? Mike |
| M. Yazel - Tuesday, 06/20/06 13:43:20 EDT |
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Hello, Im looking for a used manual fly press. Minimum 8" throat to CL and 10" bed to ram. Any leads for me. Thanks' Todd |
| Todd - Tuesday, 06/20/06 14:06:32 EDT |
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Hi all, been busy and I haven't posted here in several years now. I have a hollow cast iron power hammer base that I'm guessing originally was made hollow to keep the cost down. The hollow is in the shape of a truncated square pyramid. I want to build a junkyard hammer around this piece and don't want to mess with molten lead but would like to bulk up the weight before I bolt it to a base plate. I was wondering whether some kind of epoxy might be sufficient to secure a bunch of scrap iron inside, or whether the constant shaking of a hammer would dislodge it. The inside of the cavity is pretty rough as-cast, and there are a couple holes that I could secure bolts through to provide additional inside support. Any suggestions? Thanks, Michael |
| mstu - Tuesday, 06/20/06 14:07:35 EDT |
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Thanks Dave I will get new Victor set before proceeding. I did not realize how close to disaster I was treading. I usually use propane now,switched over about a year ago, but I had this one tank of acetylene around I was trying to finish off. |
| brian kennedy - Tuesday, 06/20/06 14:15:13 EDT |
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Re: Leaded steel. I have heard that those alloys don't forge very well. I wouldn't worry about the lead vapors, if I had good ventilation, but I would make very sure it was good! |
| - John Odom - Tuesday, 06/20/06 14:21:38 EDT |
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Jed-- those sharpeners which you drag the blade through are awful, will tear up almost any blade just as you describe. Get two Arkansas stones, coarse and fine, and some honing oil. |
| Miles Undercut - Tuesday, 06/20/06 14:24:26 EDT |
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Adding weight: Adding weight to the cast anvil is problematic. If epoxy won't stick and stay put neither will lead. In this case I would recommend a heavy base plate IF the anvil bottom is fairly flat. Many of these are as-case and very uneven. However, a few are machined and quite flat. The reason for the hollow in most conical hammer bases is to reduce shrinks due to casting. The hollow reduces the wall thickness to something more reasonable. Little Giants have hollow bases and still have a 15:1 anvil to ram ratio. |
| - guru - Tuesday, 06/20/06 14:45:10 EDT |
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If it is not too much trouble, I was wondering if someone could give me some pointers concerning working with brass. Specifically, i was wondering what kind of file to use, what kind of file strokes, what dremel tool bits work best, what drill bits work best, and how to polish it (if its much different from steel in that regard). I was also wondering if you seasoned metalworkers could suggest the easiest way to machine a slot in a brass bar to high tolerances with a drill press and files (no milling machine). Thank you in advance. Oh, and feel free to just point me in the direction of where I could find out for myself if you would be so kind. Up to this point, my searching has produced nothing. |
| Matthew Marting - Tuesday, 06/20/06 14:47:54 EDT |
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Where do you guys get your beltsander belts? I pay WAY too much for mine because I get them at sears. For a 2x42 it's $3 per belt! If you've got any links that would be great. |
| Eric - Tuesday, 06/20/06 14:52:23 EDT |
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Matthew Marting: Working with brass is not that much different from working with steel, as far as filing, cutting and polishing go. The techniques are the same, just modified a bit for the softer, stickier material. Also, there are brasses and there are brasses. All are not created equal. For filing, I prefer double-cut files in cuts from #00 to #6, depending on how delicate a cut I’m trying to take. (The higher the number, the finer the cut.) Cut on the push stroke, don’t drag the file teeth back across the stock, and keep the file clean by carding and picking as necessary. Wanna save yourself grief down the road? Buy the very best files you can. My personal favorite are Grobet, also Vallorbe. Cheap files are not worth owning. As for machining a high-tolerance cut in brass, the ONLY solution is to use a machine tool with the requisite tolerances. Any other method will not give dependable results. I may be able to cut a slot in a piece of brass that is 1/8” wide and 3/32” deep with a hand graver, but it will be just good luck if I get it within say, ten thousandths. I might get one, and the next three would be out of spec. You didn’t say exactly what tolerances you were aiming for, but when you say high-tolerance, I think in terms of ±.0005” or less. That’s “high-tolerance” for general machine work; high tolerance for the semiconductor industry is on the order of one thousandth of that. And high tolerance for earthmoving is ± a couple of inches, I think. |
| vicopper - Tuesday, 06/20/06 15:10:48 EDT |
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Eric: Try Tru-grit.com. Or Pop's Knifeworking Supply on the 'net. Google 'em. But don't expect to buy quality belts for less than a buck apiece, either. The ones that cheap aren't worth the money. Buying 2x72 belts, I usually pay about $3 to $7 each, depending on the type and grit. |
| vicopper - Tuesday, 06/20/06 15:13:24 EDT |
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Well, you got me on that one. Its just gonna be a guard for a knife blade. I dont need it within .0005, just close enough that it fits like a glove (to the human eye). I am going to silver solder it anyhow. Some knife makers in Utah have developed a method for a solderless guard that is unbelievably well fitting. It involves mirror polishing the top of the guard and using the mirror image of the file to ensure it is at a right angle to the guard. Anyhow, so far I have been just drilling through the guard and then using a spiral cut dremel bit in the drill press and getting enough of the unremoved brass out of the way so i can fit a file in there. And I am very glad you told me about your rule for files. I will get some good ones immediately. One thing first though, what cut of file is meant for fast removal of brass? Thanks again. |
| Matthew Marting - Tuesday, 06/20/06 15:31:34 EDT |
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Brass: One pointer on filing brass it to keep seperate files for brass that have not been used on steel. You need sharper files. Chips caused by filing steel, OR "nibs" of steel caught in the file will leave coarse marks in the brass. For fast cutting we used to buy special "aluminium" cutting files made by Nicholen. But, I am not sure they are still available. Scrapers also work great on brasses and I use 3M wet or dry with water for finishing prior to buffing. Brass tends to expand IN around drills when drilling deep holes. Take care to cool and lubricate when drilling. |
| - guru - Tuesday, 06/20/06 16:30:07 EDT |
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Tinkers dam (damn) There is a note from 1877 that talks about the use of dough to contain solder in patching pots, but an alternative to "tinkers dam" was "tinkers curse" in that a tinker was such an intenerant and generally worthless sort that his curse was not worrying. See below: http://randomhouse.com/wotd/index.pperl?date=20000114 |
| JLW - Tuesday, 06/20/06 17:17:39 EDT |
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Although this is not a blacksmithing question I hope those of you with an engineering background can help here. I am after the formula for calculating where 50% of the area of a donut shape would lie when measured radially from the centre. Thank-you |
| Phil M. - Tuesday, 06/20/06 17:36:46 EDT |
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donut - toroid - your question needs a bit more definition - there are many ways to cut a donut so that the surface area of the two parts are the same. Slice it like a bagel frinstance. I am guessing you are interested in the radius that sweeps out a partial toroid with exactly half the surface area of the whole thing? As if one were to stamp it with a cylindrical cookie cutter of just the right size? |
| adam - Tuesday, 06/20/06 17:57:46 EDT |
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I have had excellent service on grinder belts from Texas Knifemakers' Supply. |