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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 November 16 - 22, 2010 on the Guru's Den
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Please forgive me if I do this all wrong, I have never asked a real Gurua question before. I live in Tyler, Texas and I am looking for a business that I can buy coal from. Do you have a name of a good supplier that will ship coal to Texas? I have looked over your site and I am impressed.
Regards, Stan
   - Stan - Monday, 11/15/10 22:13:34 EST

Stan, Check with http://www.taba.abana-chapter.org or Houston Area haba. I think there is also a North Texas Blacksmiths Association. These are Texas blacksmith assoications. Use your search engines. Centaur Forge carries coal, but they are far from you in New Braunfels.
   Frank Turley - Tuesday, 11/16/10 08:48:37 EST

Coining update - thanks for the help with the physics and engineering terms, I now have a set of coin dies that are imprinting on brass planchets under a hand hammer.

The coin design is ugly as my great aunt mary, but that's my fault as a hasty artist [the dies, I'm not responsible for my aunt]. As this is the prototyping stage, I've not invested a lot of time in making the dies look pretty yet.

I made my dies on hex bar, and made a simple frame to keep them aligned but give me roomto get the planchet in and the coin out.

While I was doing all this, I had ocasion to deeply regret the sale of my P4 flypress years ago. I bought it without a definite plan for its use... and so it went largely unused. After listing it here, a gentleman came and bought it. Now I wish I still had it.

As I thought abotu flypresses more, I wondered abotu building a one... where would one obtain the screw? What sort of other machinery might I be looking for that would have such a part as a 2"+ screw and nut? looking online to buy anew one suggests that Mcmaster-carr wants almost $400 for the set.

Again, not an immediate pursuit, mostly just a cuiosity... unless one of you have such a part laying about.
   MikeM-OH - Tuesday, 11/16/10 10:39:05 EST

How many leads did that screw have? Screw press should have around 2 and a flypress should have 3-5.

I bought my Hoskins #2 in central OH for $50 back around 2003. It might be cheaper to hunt down another than to build one...

Thomas
   Thomas P - Tuesday, 11/16/10 18:47:39 EST

The Mcmaster screw was single thread, so unsuitable. I'm still hunting for a used one in a half hearted sort of way, as the drop hammer is still the main priority. I'm not likely to try to build a screw press, as I know that the scale of such adventure makes it more expensive.

On that note, here's another physics type question... I see screw and fly presses rated in tons, not psi. Is there a conversion, or a calculation similar to the my drop hammer estimation last week? I'm suddenly curious as to how the P-4 fly press I once had [advertised at 4 tons] compares to the drop hammer I plan to build.
   MikeM-OH - Tuesday, 11/16/10 20:23:07 EST

Threads and Coining: AH! For coining you want very high pressure and a single lead screw is the ticket. If you want multi-lead McMaster has that as well but the largest is 1-1/2-4 2 start.

Flypress Ratings on the small presses is to the best of my determination based on the work done in .015". This is the amount the frame stretches at the rated capacity so you cannot get more out of it. You can get less by absorbing the force in a soft material or operating the press with less pull.

Nowhere was the fact that the size numbers equaled the rating in tons published until the Kaynes started selling flypresses and I did the math. The folks that originally engineered them knew but the current manufacturers did not engineer the machines. . .
   - guru - Tuesday, 11/16/10 21:34:07 EST

Mike 4 tons = 8000 pounds. If applied to 1 square inch (about a 1.06" diameter circle) it is 8000 PSI. Applied to half a square inch it is 16,000 PSI
   - guru - Tuesday, 11/16/10 23:14:16 EST

INFORMATION NEEDED:

We are planning on making some stakes. There is no industry standard taper but we would like to make the most "standard" taper and holder. So far what we have found does not match what others say is a "standard".

We would like to hear from people that have old OR new stakes. Do not try to measure the stake angle. Measure the large end of the taper, the small end of the taper and the length of the side between. I'll do the math and determine the taper per foot and angle.

When we are done I'll publish the data.

   - guru - Wednesday, 11/17/10 00:14:51 EST

I've got catalogs old and new, none give the taper. They simply state that their stakes fit their holders. The stakes we have measured have tapers from 2° to 14° included. Its as bad as my collection of anvil tools which have shanks from 5/8" to 1-3/4". . .

The most common so far are 10° and 12° +/- 0.5°. But that is enough difference to create a bad fit.
   - guru - Wednesday, 11/17/10 01:22:28 EST

Have any of you made or seen or used a riveting anvil? (or stake?)
I like holding furniture together with rivets, but often the last couple rivets are in an awkward place to get at. I am toying with the idea of using an old truck axle (cause I have it, and it already has a dimple in the end for the rivet head) and doing a double bend or even a cut and weld to get an offset. If my shop was larger I would just sink it into the ground. As is I'm not sure if in the vice, or anvil, or just bolt the flange to a block or something.
Any and all ideas welcome.
   JimG - Wednesday, 11/17/10 09:55:27 EST

Riveting: Jim, Getting to rivets and backing them up in tight places is often a problem. I have seen anvil horns with a slight dimple near the tip that was either made on purpose or wore there from riveting. I've seen stake tools made for the purpose but this is such a specialized area that most smiths make their own.

When making gates and architectural work the backing up is done all kinds of ways. The sturdiest is a dog in a weld platen and a rivet plate supported by the dog. Sometimes special dogs are made to fit in tight places.

The most universal tool is a heavy bar (much like your axle) with a tapered end and rivet depression. This requires a helper to hold in place.

Bent and offset rivet bucks are often made as needed. The handiest is a heavy bar as above with an offset to one side about the width of the heavier bars in the item to be riveted and a heading depression in the end. Usually you want a larger angle rather than a 90°. About 110° to 120° works. This keeps the bar close to inline with the work but provides clearance for holding the tool. Sometimes a smaller matching tool is used for heading the rivet. A heavy buck of this sort could be fashioned into a stake anvil.

If you do a lot of this I would consider a heavy floor mounted or heavy based holder made of something like 2" diameter bar with a socket on the end to accept straight and offset tools. I would use 1" square shanks but for your purposes round would do. Angle the holder at about 20 to 30° from vertical and it will get under many things better than straight and work well for doing things while sitting. This is sort of along the lines you were thinking about but a little more evolved. The square or round tool socket can be made on a convenient short piece then welded to the "stake".

On a recent job Josh Greenwood found that a hand held air hammer worked very well for riveting in tight places. Because the work used hand set rose head rivets the tool simply had a large slightly radiused end on it. Heading was done at various angles from between the bars and pickets. This got to the majority of tight places where it is normally difficult to rivet.
   - guru - Wednesday, 11/17/10 10:32:32 EST

OK I'm sure this topic has been covered before in the archives somewhere...I can't find it. I am looking for the forging /knife making info on the steel used in a circle saw. It is from a sawmill end-trimmer, 20" dia., 3/16" thick. The blade does not cut, but holds carbide inserts. I had a friend slice it up with his plasma and have had good success doing the old heat anti-magnetic routine. Is there a better way with this steel that is in question?
   S K Smith - Wednesday, 11/17/10 12:41:08 EST

Medieval armour replication is all about riveting in odd locations and every armourer worth their salt has a bunch of different stakes and hammers to do it---you should see some of the crazy things people come up with to do the top rivet's in a deep conical helm where you want to peen them from the inside!

The basic answer is "If it works for you it's an acceptable method!".

Thomas
   Thomas P - Wednesday, 11/17/10 13:16:00 EST

S K SMith, See our FAQ's page, Junk Yard Steels. The answer is there. But it is not what you want to hear.
   - guru - Wednesday, 11/17/10 14:24:55 EST

Coining: Mike, Why not use a hydraulic press? I built a big one for bending but the jewelers are using a bottle jack and several pieces of all thread and three heavy plates. Its pretty compact. While the good quality jacks from McMaster Carr are pricey you can find cheaper. I want to replace the 20T jack in my press with a 50T! 100,000 pounds (45,359 kg) is nothing to sneeze at. The four column jeweler's type press is a compact bench top unit that would be economical to build. Less steel, easier to use, no double or bounce strikes, safer to use.

I made some bronze medallions a few years ago by casting. The master was machinable wax and hand carved. The castings came out fairly well but needed a bit of hand work and polishing. It was too thick (about 1/4") thus very heavy. And it had Runes on it that the person who translated for me used a wrong character. . .

If I had a lot to cast I would make copies and put at least four on a tree. . . Goes pretty fast casting four at a time.
   - guru - Wednesday, 11/17/10 14:41:27 EST

Stan in Tyler - Texas Farrier Supply in Kennedale carried coal a few years back and probably still do. They're in the Metroplex, next to Arlington.
   - Stormcrow - Wednesday, 11/17/10 18:42:17 EST

Guru, I kept an eye out for the issues you had mentioned, flexing and not being able to see the work. The dies are oriented so that they are lined up on the wide side of the ram shaft. I think its holding steady, but I'll be able to tell better when I change out the die holding systema nd get my square dies made.

As for seeing the work, not problem there. I haven't tried using a handheld tool under it yet, but so far I can see what it's doing fine. It's no bigger around than the rams on the self-contained hammers I worked on in another shop.

And the update:

I've had to do some tweaking now that it's actually wired and able to move. I extended my contact wheel so that it actually covers the whole length of the tire, I had to shave a bit off the eccentric/flywheel to clear the motor housing when going full tilt, and most importantly, I moved the pivot bolt for the eccentric to its furthest-out hole, which lengthened the stroke. It hits a lot harder now. I still think I can get more power out of the machine. I have three leaf springs stacked. I think they are keeping the helve from whipping appropriately. I'm going to study the situation some more and then probably remove one or both of the secondary springs. And then I'll move on to changing my die holding setup and maybe brace the anvil a bit more.

Ah, the joys of using home-brewed machinery!
   - Stormcrow - Wednesday, 11/17/10 18:50:01 EST

Stormcrow, In my hammer, I find that much like a Little Giant, the daylight above the work, with the ram at rest is pretty important in getting the most effective power. My machine has a nice long spring to get that whip, and I do have shorter secondary springs. They are only about 1/3 the overall lenght in comparison to the center main spring. Both are radiused, in both axis to prevent stressing the main spring. Learned that one after breaking a center spring. In my hammer a pointing finger thickness is the best daylight vs power. Yours should be different. BUT, trial and error will answer that question for you. I have a turnbuckle for quick adjustment of that daylight. Used a forged steel turnbuckle from a metal building wind brace. Nice big turnbuckle, and after 10 years use is starting to get a little loose on the threads. It has 3/4" threads.
   ptree - Wednesday, 11/17/10 19:44:14 EST

Rivet bucking. Grew up at a large general avaition airport, working at a FBO that rebuilt wrecks and built one good Cessna from several wrecks. This often involved drilling out several hundred to thousand rivet, aligning the parts, cleco'ing the parts for alignment and then bucking the mostly round head aluminum rivets. The bucked side was to the inside, often in very small spaces. Perfect for a 4' tall preteen to crawl into and buck. The rivet bucks were shop made and handheld, but the rivets were small and aluminum. The bucks were what ever would reach and work, and were often a many times re-worked tool to suit one odd job after another.
Imagine the noise inside the aluminum tube tail cone of a small two seat Cessna 150 as you buck a couple of hundred rivets, with a pnuematic rivet gun on the other side of all the 0.032" aluminum:)
   ptree - Wednesday, 11/17/10 19:49:08 EST

I have two well made, old stakes from the Kenneth Lynch Connecticut collection, probably from France. One is forged to a horizontal blade shape on top, about 1/8" x 5 1/4". The overall length is 10 7/16". There is a slight swelling at the top of the lower taper which measures 1 5/16" square. The bottom is blunt and is 3/8" square. The taper length is 3 1/8" measuring along the side, NOT projecting a vertial line.

The other is similar and perhaps manufactured by the same firm. The top is a flat, about 1" square. The bottom taper measures 1 1/8" at the "swell" and 3/8" square at its blunt bottom. Measuring the side of the taper: 2 11/16". Overall length top to bottom is 10 3/4".

I have a mushroom (dome) stake that I got at a 2nd hand store. It is pictured in the 1894 Manning Maxwell & Moore catalog, and I suspect it is of cast semi-steel. The catalog calls it a Round Head Stake. The head is 3 1/4" D, and the overall length is 12 3/4". It has a round shank going into a 1 3/4" square and that remains for a ways and is the measurement at the top of the taper (no swelling).
The blunt bottom of taper is 1" square. The taper length is 3" measuring along the side.

About 100 years ago, I read in an old English book that most stakes were carefully inlet into the end of a wooden beam; I think they called it a stiddy. The worker using the stake was semi erect with his bottom on another beam, higher than a chair, and his feet providing some support. The stiddy, if that's the right word, could be left vertical or leaned into the worker a little. If the tapers were inlet as I read, there would be no stake holder (bench plate)to contend with.

My other stakes are funky and shop fabbed. I do have one interesting combo stake which was cast at the Cranbrook Academy in Michigan and given to me by Skip Holbrook. It is designed for the vise, has two arms and a nearly 90º in the center. There is a "cows tongue" on either end, one sharp and one smooth. The backs of the arms have a smooth curve to be used as anvils.
   Frank Turley - Wednesday, 11/17/10 20:03:36 EST

Stakes Frank, Thanks for the information! The angles on your stake shanks are 17.3°, 23.3° and 14.3° +/-0.5°.

The first two appear to be designed to put into a stump. The third, the mushroom stake, is just barely a locking taper (tapers above 14.6° do not lock) and could be used in a stump or a stake holder designed to fit.

The last stake sounds similar to three arm stake called a cow's tongue stake made for jewelers but would work well for armourers and sheet metal artists. The arms are on one plane. Another three arm stake is shown in the COSIRA book Decorative Ironwork. It has arms on two planes, one a "flame". It is designed to use in a vise but we are making a modified version to fit a stake holder so you can use it both ways.
   - guru - Wednesday, 11/17/10 22:43:17 EST

Newbie here. I just inherited an entire blacksmith shop. I'm setting it up in an old horse stall in my barn. The chimney will be of metal stovepipe. It will go up the outside of the building and penetrate through a cinder-block wall. I am thinking that it would be best if the pipe just made one bend and created a side draft for the forge. I'm looking for suggestions, advice, plans, etc.

Thanks in advance
   - Roger Harris - Wednesday, 11/17/10 23:12:29 EST

Newbie here. I just inherited an entire blacksmith shop. I'm setting it up in an old horse stall in my barn. The chimney will be of metal stovepipe. It will go up the outside of the building and penetrate through a cinder-block wall. I am thinking that it would be best if the pipe just made one bend and created a side draft for the forge. I'm looking for suggestions, advice, plans, etc.

Thanks in advance
   - Roger Harris - Wednesday, 11/17/10 23:12:54 EST

Newbie here. I just inherited an entire blacksmith shop. I'm setting it up in an old horse stall in my barn. The chimney will be of metal stovepipe. It will go up the outside of the building and penetrate through a cinder-block wall. I am thinking that it would be best if the pipe just made one bend and created a side draft for the forge. I'm looking for suggestions, advice, plans, etc.

Thanks in advance
   - Roger Harris - Wednesday, 11/17/10 23:13:07 EST

Coining and hydraulics... So I hadn't thought much about hydraulics, having never used them outside lifting a car. Google images for a jeweller's press show either 4 bolt/3 plate arrangement with the jack between the bottom and middle plates OR a heavy plate arch over a jack. Are those that you mean?

So, in that sort of press, a 20 jack would produce 40,000psi or 51,000 on an 1 dia coin?

Would this be a case for 1" or thicker plate? 1" or thicker threaded rods?

This is something I'll have to price out... If I can afford the 20T air driven jack, it'll mean much less work for me.

   MikeM-OH - Wednesday, 11/17/10 23:28:40 EST

Hydraulic Press: Yep, those are the ones. Here is mine if you have not seen it. Needs new photos. . .

20T Hydraulic Press.

Its way over built and a little cramped. But it works great. I've bent 1/2 x 2" CF bar cold to a 90 degree bend and last week we bent a stack of 1/4 x 3" pieces to a 90 with a 3/8" radius to match some structural tubing. Worked perfectly using a primitive fixture built the same day.

The one that came up near the top of my search was a YouTube video of a pretty crappy press being sold to Jewelers. I'd be embarrased to sell something that sloppy, especially to jewelers.

Shortly after photographing mine I fit a large diameter knob to the control valve. Makes operation much faster.

If you don't let the cylinder return all the way, just backing off enough to get the work in and out, cycle times are pretty fast. An air operated cylinder would be a big waste unless you need production rates in the thousands per day. I've made hundreds of parts in a few hours with mine.

One thing to know about presses is that the springier the frame the more energy that is stored in them and the more that can go wrong. If something slips or breaks the stretch is a lot of spring and motion.

I you have access to any kind of machinery those heavy plates can stand some holes for mounting dies or die sets. I'd put a 3/4" or 1" hole in the top plate for punches or a "ram" to improve visibility and access, a set screw from the side to hold the punch or ram. I'd also drill and tap a number of 5/16" or 3/8" holes to bolt things down. The movable platen should have a ring to keep the jack centered. Bend and weld. .

Between a knob on the valve and a few tool mounting holes you'd have a nice little press.

Your math is correct. Because this is not an inertia press the spring in the frame does not effect the total force.
   - guru - Thursday, 11/18/10 00:59:52 EST

More about operating the press. For coining where the needed motion is only 1/16 to an 1/8" the job will be done in one or two strokes of the lever. If you only back off a little, then the total strokes are only 4 or 5 and go very quickly.

One part to remember is the return springs. These jacks do not return on their own. They need some load or a force. If you use threaded rod columns you can use compression springs abound them. HOWEVER, remember that they do not close to 0 height. Tension springs work but need to be pretty heavy. The ram I suggested would create space that would allow coil springs on the rods. It doesn't have to be removable, it could be welded on.
   - guru - Thursday, 11/18/10 01:08:07 EST

Bench Top Hydraulic Press
Bench Top 20T Hydraulic Press


This is what I am talking about. It uses the shorter of the 20T Hydraulic Jacks sold by McMaster Carr. Same price as I paid 35 years ago for a BlackHawk. . . . I show four 1" columns. With the four columns you need four springs OR two diagonally. With slightly wider plates it could be built with only two 1.25" columns. This would allow the top plates to be half their width (5 x 11). You could shrink it more with welded construction.

For twice the price you could put a 30 ton jack on it and get some serious umph!
   - guru - Thursday, 11/18/10 02:44:54 EST

Even more. . . about the press

The problem with parallel column presses is what's called an L/D (L over D), length over distance lock. This works exactly like the locking taper I mentioned above for stake shanks. In the case of the press above the angle between the lower far corner of the guide hole on one side to the upper on the other is about 9°. Definitely a locking angle. Since the distance diagonally is greater it is a lower angle and more locking.

To prevent this problem you can do a couple things. One, make the holes so loose they never touch. But then you have no guiding and the parts can get way out of alignment. Another is to make the plate thicker. In this case it requires a plate almost 3" thick! Also not a very good solution. The best way is to use long guide bushings or guide tubes. These could be added to the bottom of the movable platen. They do not have to be a precision fit. All they need to do is prevent the platen from tipping enough to bind on the guides. So, the looser they are (such as pipe), the longer they need to be.

The thing about L/D locks is they either work or they do not. If you want a lock such as on a clamp of stock stand then use a 10° angle. If you don't want a lock then be sure you have a 20° or more "cocking angle". In one case it will always lock and in the other it will never lock.

The press above will work. But if the platen tilts it will lock and hangup. If this happens using the force of the press it will tear things up. If it hangs a rap with a mallet will unlock it.
   - guru - Thursday, 11/18/10 11:03:42 EST

All the rapping with a mallet didn't get the baby out last night... but at 9:54 PM the wife had to get a C-section and gave birth to little Eli. 8 pounds 1.3 ounces (just the size of my hand sledge) at 22 inches! I'm working on a webpage devoted to him on my site. In the meantime, here's a few video clips on YouTube.

http://www.youtube.com/watch?v=LjMdfXecKPc&feature=&p=4D6D8E7B8CFC851A&index=0&playnext=1
   - Nippulini - Thursday, 11/18/10 11:37:41 EST

Congratulations!

Your life will never be the same from this point onward. Not only the responsibility but the way you feel about many things.
   - guru - Thursday, 11/18/10 12:37:35 EST

Congratulation Nippulini!
   mstu - Thursday, 11/18/10 12:48:32 EST

Press Update: After posting about the L/D lock I updated the drawing to show guide tubes and the corresponding non-locking angle.

I also noted the ram should be a little longer than the shut height (solid height) of the springs. I wrecked the guide system in my press when the spring went solid and I was watching the part I was pressing and not the spring. . . If you use tension springs below the platen this is not a problem. But tossing a couple compression springs on the tension rods is much easier than making connecting point for tension springs and preloading them.

Depending on your cache you may have to refresh the image itself, not just the page to see the changes.
   - guru - Thursday, 11/18/10 12:50:07 EST

Stakes-
Kevin Potter is currently manufacturing stakes, in the USA, for sale to the jewelry and silversmithing community.
( I know, we dont make anything anymore, and nobody makes stakes, but Kevin refuses to listen to popular wisdom)
Anyway, you should ask him what taper he puts on his stakes- he sells them to jewelers and schools all over the world, including exporting to China and India, and I would imagine he has arrived at a suitable "universal" taper that fits the majority of anvils and stake holders.

his website is www.potterusa.com

he is a great example of swimming against the stream, and just doing it.
He makes a whole line of metalworking tools, himself, in his house, and has within 2 years become a world presence, and is now sold by places like Otto Frei, and exports worldwide.
Kinda proves that if you cut out the MBA's and the conventionally accepted Wall Street Way of thinking, great things can happen...
   - ries - Thursday, 11/18/10 15:19:44 EST

In the UK we refer to the shut height on a press as the maximum amount of daylight between the ram and bolster (ram at TDC), is it different on your side of the pond?

Nip, Corngratulations :)
   - John N - Thursday, 11/18/10 18:54:22 EST

Well John, what the heck do you call it when the ram is all the way down (BDC)? "Open height"? "More shut height? ;)
   - grant - nakedanvil - Thursday, 11/18/10 19:04:40 EST

I was always taught that daylight height ina press is the daylight remaining between the bottom of the ram and the top of the die or bottom platen.
   ptree - Thursday, 11/18/10 19:22:00 EST

I should add to the above remaining when the ram is all the way down.
   ptree - Thursday, 11/18/10 19:22:36 EST

Yeah, to me the "shut-height" is, well, when it's shut.
   - grant - nakedanvil - Thursday, 11/18/10 19:49:43 EST

If I remember right [possible], daylight on a punch press is with the ram at bottom dead center , and the pitman screw all the way up.
   - Dave Boyer - Thursday, 11/18/10 20:25:41 EST

A better way of defining things is shut hight and required stroke, no good if You can't get the part out.
   - Dave Boyer - Thursday, 11/18/10 20:28:24 EST

According to the Society of Manufacturing Engineers Website: http://www.toolingu.com/definition-400300-11563-shut-height.html
the shut height is: "The distance from the slide face to the bolster when the slide is at bottom dead center".
   - grant - nakedanvil - Thursday, 11/18/10 20:51:22 EST

According to the Society of Manufacturing Engineers Website: toolingu.com/definition-400300-11563-shut-height.html
the shut height is: "The distance from the slide face to the bolster when the slide is at bottom dead center".
   - grant - nakedanvil - Thursday, 11/18/10 20:52:05 EST

According to the Society of Manufacturing Engineers Website: toolinguDOTcom/definition-400300-11563-shut-height.html
the shut height is: "The distance from the slide face to the bolster when the slide is at bottom dead center".
   - grant - nakedanvil - Thursday, 11/18/10 20:54:09 EST

Sorry, it kept not showing. Thought it was the web address being blocked as spam.
   - grant - nakedanvil - Thursday, 11/18/10 20:56:09 EST

Shut Height: In the US the shut height is where the spring becomes solid or in die sets they are closed and cannot travel farther. Sometimes the shut height of the springs determine this, sometimes other parts of the dies.

Generally in die sets the working travel should be some safe distance from the shut height and the press properly adjusted to this safe distance. If the die set is free standing then this usually results in air space or free air between the top of the die set and the ram. However, many die sets are designed for specific presses and there is no gap or air space. These will actually preload the springs in the die set and ocassionally there are reasons for this.

Other die sets have the top attached to the press and need no return springs. These may have a stripper plate that has springs but they are not the primary return method. Having the press pull the punch out of the work has the advantage of not reducing the capacity of the press with springs that must create significant force to pull the punch out of the work. Shut height is still when the dies bottom out with or without work in them.

The reason this is important is that punch presses create 5 to 20 times the force that the frames are rated for. If the ram bottoms out on anything then SOMETHING most break. Usually it is something in the press clutch but sometimes the crank shaft or even the frame breaks. . .

I've designed and built die sets that used all three methods above including spring loaded pressure pads to support thin material while punching. The only type of die set I have not designed is one with automatic feed. These are an interesting piece of work that use either levers or a rack and pinion to feed strip stock into position with every stroke. Very high production stuff. Turn on the press and watch it convert an entire coil of metal into punched or blanked and bent parts.
   - guru - Thursday, 11/18/10 21:08:59 EST

Presses:
Guru, thanks for all the info. This looks looks much less work than the drop hammer, but I'll have to buy materials for the frame. I'm going to check prices for h-beam and see if I can afford to do this soon.

I really like the look of the single plate arch, but I don't know much about how to calculate a safe pressure. I can get a big block O cut out of plate, but what thickness? 1"? 1/2"? Much less welding than separate pieces of h-beam, by probably much more expensive.

I need to start drawing up parts lists and sketches.

Despite repeated disappointments, my lazy mind wanders to harbor freight presses....
   MikeM-OH - Thursday, 11/18/10 21:35:43 EST

Shut Height II: The problem above is we have three different things with "shut" heights.

1) Springs when they become "solid"

2) Die sets when they "bottom out" with work in them.

3) The press itself which cannot have anything that prevents it from reaching "bottom dead center". If its not clear to pass this point in rotation something usually breaks.

All different, all the same, and all found in the same mechanism.
   - guru - Thursday, 11/18/10 21:42:20 EST

http://marco-borromei.com/press1.jpg
This is what I was thinking for the block O frame press. This was intended to [1] minimize welding at critical points and [2] minimize waste on the heavy plate I'd need cut. The "donut hole" gets cut in three slabs to make the jack table, sliding platform, and roof. With right triangles of thinner scrap plate I already have welded in as supports, I have a press that stresses NO welded joints. Lots of bits are NOT drawn in, like supports to keep the sliding plate in place and parallel to the top plate, or threaded holed for mounting tooling, or return springs.

As drawn, all sides of the O are 4" wide. What remains to be seen is whether this is cost effective to cut from 1" plate, or what else might be available/strong enough. Is 1" overkill, would 1/2" work? A lot depends on whether the local steel shop carries/cuts thick enough plate.

Now, if something is obviously wrong here, feel free to say so.

Note that I'm trying to avoid 2 things that are a bit beyond my capabilities right now: welding plates thicker than 1/4" to withstand press stresses , and drilling holes larger than 1/2".
   MikeM-OH - Thursday, 11/18/10 21:54:37 EST

TGN: Best regards to the wif; she got to do the hard part!
;-) Another exciting adventure begins!
   Bruce Blackistone (Atli) - Thursday, 11/18/10 22:08:20 EST

For more on coining and hydraulic presses see "The Engineer's Thumb" by Sir Arthur Conan Doyle.

To TGN Congratulations.

On stakes email me.
   philip in china - Thursday, 11/18/10 22:09:19 EST

Cheap presses. . . I've seen LOTS of these with severely bent frames. The worst are the ones made by "American Industries" using a press bent top beam. They typically have "30 Tons" on the frame and come with a 20 ton jack that will bend the frame into a pretzel. We've had a number of these tools in our shop and the first thing they need was to spend a couple hours with a file removing all the saw and shear burrs. . . Just flat out dangerous.
The springiness in the frame is also dangerous.

Plate frames Calculating the stresses on the circular plate frames such as used by Potter USA is very complicated. There is no standard model in the engineering references. There is probably a good (expensive) engineering program that does it easily. The failure mode is to buckle like a pretzel.

Engineers like clearly definable force vectors. Look at bridges with their pin joints and parts clearly in tension or compression. Few bending moments other than in the deck. Big presses use tension members that have clear forces that are easy to analyzed. Simplicity is the best way to avoid the unexpected.

C frame presses, while not so simple are well understood and have fairly clear engineering models. But there is nothing as simple as a pinned H frame press.
   - guru - Thursday, 11/18/10 22:51:23 EST

I am looking for a recipe for microcrystalline finishing wax. At some point, in fairly recent history, I saw someone posted an article on how to make an equivalent to Renaissance Wax.

Does anyone recall that article? I cannot find it online and seem to remember finding it there before.

thanks,
   steven Bronstein - Thursday, 11/18/10 23:06:39 EST

Mike's Press: A frame like this bends in two directions. The upper and lower "beams" bend outward, the sides bend inward (largely due to the forces from the top and bottom). The most highly stressed parts are the top and bottom. I would make them taller (wider?) than the sides but about 50% (6" vs 4").

The most highly stressed part on the frame is the inside corners. Make these a nice large radius (say a 2" radius) to relieve stress.

Deflection increases by the cube of the increase of the width. In other words, keep the frame as narrow as reasonably possible. But don't cramp yourself.

The problem with flat plate frame members is angular deflection. In structurals this is prevented by the flanges. When using flat plate the slenderness ratio of the plate comes in. In order to optimize the thickness (make it thinner) you have to determine the buckling force. Make a T section out of it and you reduce the buckling. . . but only partially.

I'm sure (gut feeling) that the 1" plate is heavy enough. But 3/4" might do . . .

I've built test stands for 50-60 ton loads in tension and used flame cut holes for the pin connections. Not optimal but cheap.
   - guru - Thursday, 11/18/10 23:39:31 EST

I understand what you mean about buckling. Looking closer at the Potter press frames, I see they're horseshoe shaped, giving the inside a nice radius and no weak corners... obviously stronger than the squared corners i drew.

I guess most of this will come down to material costs next week when I can get down to the steel yard and ask. I also need to get a width measurement on the proposed jack base so I can adapt which ever design to be as narrow as possible. I only intend this for coining and my die holder frame is 4x4", so I can make whichever frame narrower when I measure the jack.

May I ask roughly what size h-beams you used to make you press? I'm not sure what's available, but that' would give me a good starting point.
   MikeM-OH - Thursday, 11/18/10 23:50:59 EST

Microcrystaline Wax: Steven, Are you looking for how to make the wax (an industrial chemistry question) or how to use the wax?

Finishing mixtures are wax and solvent to make a paste out of the wax. The less solvent the thicker, the more the softer. Usually the wax is melted with heat and the solvent added. Care must be taken not to overheat the mixture as solvents and heat do not agree. This is how all paste waxes are made.

Proprietary products have other things in them. Hardeners, driers, fillers, coloring and are formulated and tested by professionals.

So why do you want to make an amateur version of a finish that is readily available from our advertisers?
   - guru - Thursday, 11/18/10 23:52:36 EST

Steven,

Go to Wikipedia and look up "renaissance wax". The article gives two formulations "soft" and "harder".

I think I may be the guy who first researched this for the BS community. I bought a 4 oz can of Renaissance Wax for $25 and decided there HAD to be a chea . . . uh more thrifty way.
   Rudy - Friday, 11/19/10 00:11:48 EST

My press is much heavier than it needed to be largely because I had the steel. The frame is S 10 x 25.4# (I) beam. Which means the top only deflects .000064" at full load not including the added rib. . . I was limited to a hand drill for many of the holes so it is put together with 3/8" bolts and these are probably the weak link. To upgrade it to 50 tons I would need to make the holes larger or add more. Either way it is tough to do on the welded frame. I'll probably worry the holes out to 1/2" if I ever have the need for the upgrade.

McMaster-Carr has dimensions of their jacks. I suspect they are close to others but I would not assume too much on this point.
   - guru - Friday, 11/19/10 00:15:28 EST

TGN, congratulations to you and Mrs. TGN! That is a fine looking young man!
   quenchcrack - Friday, 11/19/10 07:27:30 EST

Dear Guru,

It is a point well taken that since a great product already exists why not just use it and it is only the volume expense that makes it less than an ideal solution.

I have a production shop and have been dipping my work in a mixture of wd-40,thinner, and linseed oil. Though this has worked well for many years, I have some products that are difficult when it comes to cleaning the residual drips. We would usually use Butchers Wax for these situations. The Renaissance Wax does work better but is too expensive for me to use on a production basis.

I was not looking to take Renaissance's recipe but I have seen other people who have come up with their own versions of a microcrystalline wax which was more cost effective for a volume use.

Thanks
   Steven Bronstein - Friday, 11/19/10 09:18:24 EST

Rudy,

I had gone to the Wikipedia site and had skimmed right over the recipe.

Thanks for you help.
   Steven Bronstein - Friday, 11/19/10 09:21:52 EST

I had a fellow who raises beautiful vessels order some custom stakes from me, in part because the Potter stakes are made from 1018 and he was denting them. I'm making his from 4140. They're designed to be held horizontally in a vise.

In fact, I need to work on one today!
   - Stormcrow - Friday, 11/19/10 11:55:51 EST

So I've increased the new hammer's power of its blows by increasing the length of the stroke, but my springs are now preventing me from getting as much power as it could. There are three fairly heavy truck (not pickup) springs in the helve, all about the same length, shackled together at the ends. Thinking about it, not a great way to get the spring to whip. I've actually had to crank the dies down to where there's no daylight between the die and the steel being worked in order to get it to hit, which I know isn't a good thing. So I need to alter my springs.

Here's what I'm thinking: If I shorten the top spring to about 1/3 the length of the main leaf (in the center) and arch the end a bit to reduce stress per Ptree's suggestion, can I leave the bottom spring long on the ram end of the pivot as long as it's not shackled to the main leaf? Seems to me like that wouldn't affect the hit, but could help support the main leaf as the ram is being lifted. Make sense?

For that matter, what about leaving the top leaf long on then back side of the pivot to help brace the main leaf on the down-stroke? Seems to me that it would preserve the whip on the fore-end and reduce it on the hind end, maybe delivering more force in the blow. Is that a good thing? Am I thinking about this right?
   - Stormcrow - Friday, 11/19/10 12:06:01 EST

I am looking for an old friend..his name is Tim Hibbs..and I remember he was a darn good blacksmith, I believe he had won a scholarship to Fairmont State College in WV back in 1993. I know this is a long shot..but if you have any information..I would love to catch up with him.
   erin - Friday, 11/19/10 12:50:32 EST

Your spring logic seems to make sense, I'd have to lay it out on paper to be clear. On our new hammers we used leaf springs. Adding leaves on one side does nothing put can preload the spring. Adding on the other does what you expect, makes the spring stiffer. But this is with a DuPont toggle linkage which applies force only one direction on the springs.

The problem with the spring helve hammers is the dynamics of the spring. Some folks just accidentally hit it, others do not. Too heavy, too light, too long, too short. . . all relative to mass, travel and speed of operation. A LOT of variables.

In the hey-day of the industrial spring helve they had all kinds of linkages and adjustments to make the things perform properly. Here are two from Sweden.

fjäderhammare

These were very popular hammers in Sweden and are still found all over Europe. They are properly called "spring hammers" as translated in in every language.

It seems to me that these hammers would benefit from a linkage that works like a shaper (or in reverse) where it moves faster in one direction than the other.
   - guru - Friday, 11/19/10 13:13:02 EST

Below is a repost from today on Farwest forge. I post it with great concern for our friend.

Rich Waugh

Thought I should let you know that Rich Waugh was diagnosed with dengue fever 10/12.
On 10/14 one of his lungs collapsed and he is in the emergency room in the hospital in St. Croix. They installed a chest tube.
On 10/16 Rich was still in hospital, still had chest tube (he just won’t let go of anything ), and the Doctor discovered he has sever pneumonia in one lung. They gave him IV antibiotics. There were talking about continuing the antibiotics and then sending him home Thursday or Friday.
On 10/18 Rich continues to be stubborn as usual ☺☺. He has not improved regarding the pneumonia, he now has sepsis of the blood, and managed to pull out his chest tube somewhat prematurely. Prediction is now a week more in the hospital. He is currently on three killer IV antibiotics. Doctors are zeroing in, somewhat, on what to treat. Not much to do but wait and pray… ..... And that's why I'm posting this here. Do what ever you'd like to send positive stuff his way. He needs it, the doctors need it, his wife, and family need it.

   ptree - Friday, 11/19/10 14:08:43 EST

Stormcrow, I have short helpers above and below the main. I believe from watching, that whip in both directions increases the power of the hit, since upward whip just cocks the spring more for the downward blow.
Play some with speed as well. I found that my hammer is better at about 180 blows/minute than at 240. Lets the dynamics of everything on my hammer hit the sweet spot.

I tried a tapered single leaf and was sorely disappointed.

When I say radiused in both axis, I put a typical full radius across the wide way of the spring, as wel as a ful radius on the thin way.
   ptree - Friday, 11/19/10 14:15:52 EST

Rich is a tough bird and its surprising to see him struck low so fast. Bad bugs. I'm sure he's in all our prayers.

RICH! Don't let the buggers get you down!
   - guru - Friday, 11/19/10 14:31:17 EST

It's been tough knowing about Rich's struggle these last few days. He let several of us know about the Dengue diagnosis and then was suddenly in real trouble. Rich's brother Riley has been keeping us updated when he can so I'm sure Jim will pass along any significant news to all. In the meantime please pray for him if you do or scratch your dog if that's what you do instead, but keep him in your thoughts and hope for a quick recovery. I'd ask everybody to please resist the urge to call the house as I know that his wife is thoroughly worn out from this strain and doesn't need any extra hassles right now. If you want to send a card you can find the address on Rich's website. (Carribean Blacksmith) Steve G
   - SGensh - Friday, 11/19/10 18:27:55 EST

Holding good thoughts and prayers for Rich.
   Frank Turley - Friday, 11/19/10 21:01:09 EST

Guru,

I am very SORRY!!

I misunderstood the type of staking tools you meant and really was trying to tell you about a special book, the od taper isn't important in those type and why through how they are used. I totally screwed up as you were referring to the armour and tinner stakes.
Would you PLEASE consider still working on the special project that has been in the works for a great deal of time. I know you are so busy with many things. It would be wonderful for all.

I hope all goes well with Rich and I will keep him and his family in my thoughts.
   - Burnt Forge - Friday, 11/19/10 21:31:39 EST

I don't know Rich but Jesus does, will send up a prayer for him. It seems like I heard something one time, tell me if this is right or not. Instead of tapeing off parts to be painted, rub vaseline on parts that you do not want paint to adhere to, then wipe it down. Is this or anything similar to it correct ?
   Mike T. - Friday, 11/19/10 22:14:30 EST

Mike, Paint and any kind of grease or oil is problematic. In your example the grease may not be just where you want it but anywhere else you touch the part. Solvent in the paint may pick up the grease around the greased area and not dry or setup properly. There are a whole plethora of problems related to this. Remember the first rule of painting is CLEAN CLEAN CLEAN. And the second rule is, clean clean clean. . .

While I've done my share of taping and will do so again, it is something to avoid if possible as it often leaves adhesive residue that is difficult to get off and pulls bits of paint loose.

Back when I painted automobiles we stripped everything off that we could including all the large and small chromed parts and replaced them after the paint job was finished. On higher class jobs we went around all the rubber such as windshield gaskets with black rubber paint and a fine paint brush to cover the places that paint got under the tape. Good paint jobs (on anything) are hard work.
   - guru - Saturday, 11/20/10 02:36:52 EST

SHUT HIGHT:
As a tool and die maker, When I want to know what the "shut hight " is I am refering to the machine the die or tooling will be used in.
The customer or engineer will then give me the min and max shut hight of the machine and I'll have to build the tooling to fit that or recommend a larger or smaller machine.
The stroke of a crank press is always the same (that is how it develops its rated working tonnage)If you don't have your "shut hight" adjusted properly the tooling either fails to complete the prosses or crashes the machine. As the Guru points out, there are other factors that come in to play when dealing with muti-stage tooling but, all those parts still have to meet the min-max shut hight of the machine, to work. A hydraulic press goes until it reaches the required tonnage or, pops a relief valve but they can have a solid stop too that is some times set idependent of the shut hight of the tooling.
So Grants definition is the most accurate here.
I should add that ptree's beloved upsetters do not work the same as a crank press. I beleave the upsetter is just a big,unstopable crank arm wear as the crank press relies on the momentum held in the flywheel to do its work.
Am I right on that ptree?
   - merl - Saturday, 11/20/10 02:50:55 EST

I need some advice on fixing a bad paint job.

For various reasons I needed a 7ft long computer table, so my dad built a frame out of 2x4's and used some horrible paint on it. He used a layer of primer first, thinking it was white paint, then used a layer of latex based paint; both had obviously gone bad because the paint was peeling off and ruining everything just from us handling it. I scraped off what I could from areas where I would be regularly making contact while using the table and then put on a layer of matte spray paint. I did notice that the spray paint's solvent was dissolving the old paint.

Is there any product out there that I could use to coat the frame so that none of the remaining latex peels and scratches off so easily? Preferrably something thick and viscous so that it doesn't spray all over my room.

Also we're using two particle board planks, originally meant for use as shelving, for the table top. Is there any way to disguise the gap where they meet? I don't think there is any filler or paint out there that matches the white plastic that the boards are covered in. Or is there any slim material suitable for a table top that I could place on top?
   Nabiul Haque - Saturday, 11/20/10 02:54:34 EST

Congradulations to your wife and child Nip! (you had the easy part!)
I have to say the C section situation always makes me a little shaky but, I'm glad everything turned out well.
My first son was 8lbs+ but the second one was 10 lbs 13oz (so look out!)
Best wishes to all your family.

merl aka Eli
   - merl - Saturday, 11/20/10 03:08:30 EST

Nabuil, Good paint over bad paint never works. I've seen $20,000 house paint jobs flaking in months because they were applied over old bad paint.

Not knowing exactly what you have all I can recommend is to strip all of what has been applied and then start again. That means paint stripper followed by wax remover (to remove any oil from the wood). These are water based and after stripping the wood should be well washed with mild detergent and water than let dry well (a week or so).

Then, anything you apply should be compatible with the anything else you use. Many paint types are not compatible with each other (as I think you have found out). Lacquer based paints (possibly your spray paint) cannot be put on over oil based paints because they soften and then curdle the oil based paint (sort of like paint remover). Oil based paints CAN be applied over lacquer as soon as the lacquer smell is gone. Water based paints such as latex cannot be applied over fresh oil based paints and primers (will flake forever if it dries at all). Polyurethanes have a whole different set of compatibility issues. Read the manufacturers' recommendations on all these products before use.

Often you don't see these compatibility issues if the underlying paint is thoroughly dry. So folks don't often see the problem. Fresh paint is a different story.

Filling gaps in furniture is difficult. Wood shrinks and expands, applied loads open and close cracks. You can fill a gap in a table top with many things and even the best will show a crack in very short order (days if not weeks).

There are several things you could cover the desk top with. Masonite (that dark drown dense particle board) works OK and is pretty cheap. It comes in 1/8 and 1/4". It could be glued down with a heavy contact cement and be quite permanent. Or you could just use a piece loose. The down side to Masonite is that dings and scratches raise a fuzzy burr and sanding makes it worse (weird stuff). Masonite is often used for underlayment for tile floors.

Formica and its various cousins vary a great deal in price. But it is hard, washable, fairly heat resistant and quite durable. It too is applied with a heavy contact cement. It is very thin, about 1/32 to 1/16". The problem with formica is making a pretty clean edge. If you know how and have the tools its easy. If not then you just need to put up with an ugly raw edge. . . Formica is what covers most kitchen counters, many tables, school desks, many other types of furniture. There is attractive expensive stuff that looks like lacquered mahogany and cheap multicolored stuff that would make ugly trash can liners. . .

THEN there is a big honking piece of sheet metal. . .
   - guru - Saturday, 11/20/10 04:01:23 EST

If the gap isn't too wide and doesn't move too much, you could always cover the top with Contact paper. Not a very elegant or durable solution, but cheap and easy to replace when needed.
   Mike BR - Saturday, 11/20/10 08:22:19 EST

Merl, the upsetters that I know, are pretty much a mechanical forgeing press, laid on it side, with the addition of a set of cams and toggles to close a "Grip slide" in addition to the crank throw that moves the "tooling slide"
They all have a large flywheel. The prime mover, an electric motor, turns the flywheel by belt. with say a 12" sheave on a 200 Hp motor turning say a 8' flywheel on a "9" size upsetter. Inside the flywheel is an air operated clutch. When the pedal is depressed to run a stroke, the clutch engages, and the flywheel turns a "Backshaft" that runs clear across the back of the machine. This back shaft will have a big plain pinon of say 24" diameter that engages the bullgear. The bullgear is keyed to the main crank. The bullgear will be about 12' in diameter.
The crank starts to turn, and the cams on the crank throw the toggles and the grip slide slams shut, gripping the billit, just outside the area to be upset. The gripslide carries the die halfs that form the backside of the upset area. The tool slide is still coming forward, and reaches the work, pushing the billet into the dies on the grip slide, and also forming the end of the bar. The crank goes over center and begins to retreat, and near the end of the cycle the grip slide cams opens the grip slide.

In most upset forge operations between 1 and 5 progressive impressions are used to get the final shape.

In the 10" upsetter that we used to make rough terrain loader axles from 5" to 6" 4140 bar, the machine pushed about 3-4 feet of that bar end back on itself to form a 22" by 3" minimum thickness flange on the end of the bar in 5 hits.
You can't move that much metal in one stroke in a mechanical, so progressive. First makes a long taper that swells an inch or two of the diameter near the base next to the gripslide. The next hit makes a much shorter, much fatter taper, the next a thick pancake, the next spreads the pancake and the last finishs that flange. It takes about 1700 to 2400 ton as the crank hits BDC.
And yes, if the process goes wrong, say a cold billet, or a too long billet, or a billet not aligned, it getts very ugly if the slide toggles don't "break over" and let the tool slide stop while the crank goes on. A break over event is known as it happens by everyone in the shop, since about 2400 tons is suddenly released. You hear and feel it thru the floor. I was about 50' from, and inside an shop office when a 9" upsetter went wrong and the toggle springs were too tight. The crank broke. The heat treated 4140, forged crank broke through a 32" section next to the bearing. Really felt that one!

Too my knowledge, every mechanical forging press uses some variation of the flywheel turning a crank, and is similar to a punch press in the need to properly work with shut height to get a proper fill on the die and to not break the machine.
In the US two big makers of both forging presses and upsetters were Ajax and National Machinery. Both companies shared components between the upsetter and press line since they were so common.

And while I know upsetters somewhat and presess somewhat, I respect them, and have a love/hate relationship with them. I was a maintenance manager with the responsibility to keep them running, and also held the safety and environmental responsibility at different times in that same shop. These are big, old machines made from a time when steel was cheap and so were replacement workers.

I was also around steam drop hammers. Big ones. I was NOT the maintenance manager or Safety guy in that shop, so I grew to love to watch them and be around them. Had I had to maintanin them maybe less love:)
   ptree - Saturday, 11/20/10 09:34:35 EST

Flywheel "punch" Presses, forging machines and upsetters all have that characteristic that once you trip that clutch you have released an unstoppable force. Try to stop it, something breaks. So tooling is carefully engineered. But IT does hit the fan once in a while.

This is why I tell people that you cannot make a forging hammer out of a punch press. You CAN, but the entire process must be engineered for specific dies, specific stock and proper work temperature. Then the person setting up and maintaining the press MUST understand all the basic parameters when setting up the machine for that job. . Most folks don't have the engineering skills or millwright skills.

What people don't understand about these machines is that when they are operated only about 15% to 20% of the energy in the flywheel is used at full capacity. That means that it has 5 to 7 times the energy than rated. But for economic reasons the frame and many other parts are only designed to take about a 2 to 3x overload. Not only does the press have a huge amount of kinetic energy, if you try to stop it instantly then the force is INFINITE. Or is would be if something doesn't deflect, bend of break. At 5x the rated load something usually breaks.

Flypresses are the odd man out in the flywheel press business. Their frames are designed to take the full force of the very slow turning flywheel. In order to withstand that infinite force at reversal the frame stretches, absorbing the kinetic energy over a safe distance. Then the frame returns to shape reversing the motion of the flywheel through the screw. Due to this stretching the presses are limited in force and rated at that.

   - guru - Saturday, 11/20/10 10:43:23 EST

I think the white plastic already on the boards is a very thin layer of formica. My old table was made of formica and man what durable stuff, survived many soldering iron and blow torch burns. The gap is very small, about 1/3 of a millimetre maybe, the problem though is that due to the layout of the table, only one of the board's edges could be directly on top of a support beam running parallel to the edge. The other board is resting on top of beams running perpendicular to it's length, so when a load is applied on it, it warps upto a millimetre in in depth compared to the supported board. But this is before we've secured the boards to the frame; my dad is telling me to put wood glue where the edges meet and then screw down the top.

I've never seen contact paper before, but from looking at videos I think it would be too thin. I need the material to disguise the gap and make a smooth writing surface. I was wondering if non textured vinyl flooring would work, but I don't know if that is even available.
   Nabiul Haque - Saturday, 11/20/10 11:55:57 EST

Oh I forgot to ask, how about applying contact paper or stapling vinyl or something over the frame? It wouldn't look pretty, but as it stands the frame is just some badly painted, not properly sanded 2x4s. I basically need this to be useable until summer when I will have the time to fix it or build a new one.
   Nabiul Haque - Saturday, 11/20/10 12:07:28 EST

Contact Paper: My ex wife, a former school teacher was the queen of contact paper (or plastic - which is what it really is). She covered books, boxes and even some furniture with it. . . While it looks bright and shiny, and rather tacky, when fresh it rapidly degrades to trashy and decayed looking. Any gaps underneath become tears, corners rapidly wear through and it peals. . .

When used on a good hard surface with trim to cover edges, such as used on an automobile "wood" panel it holds up well. But on the wrong surface it can be pretty trashy.

Linoleum: They make a special linoleum for covering drawing boards. Its about 3/64th (1.5mm) thick and self healing for use of compass points. The only colors I've seen are a soft yellow and a dull green (one on each side). It is a very good writing surface. It will span very small gaps but doesn't make a drawing surface at the gap. It is not cheap. $100 to $150 to cover a drawing board.

You MIGHT be able to find something similar at a flooring supplier. The often have left overs.

I would strip the paint and use varnish on the wood. The paint stains that won't come off will give it antique look. . .

   - guru - Saturday, 11/20/10 14:12:11 EST

Unfortunately I don't have the time to remove the paint and refinish it, it's near the end of the semester and I'll be dead of exhaustion by christmas. Just the day or two that I spent on this is extremely valuable time that could be weighted in marks lost as a result of not doing work. Looking at it now that it's assembled and the top is basically finished, the spray painted wood doesn't look that bad and the latex stuff is at the back where I can't contact it.

Yeah the linoleum is way too expensive for this, the table is only worth $50 in materials. We put the boards together in a way that the writing part of the table has almost no gap and the computer part has a wide gap which I sort of filled with drywall compound. I'll head to home depot and see what I can find for a surface. Transportation is also a problem, a 2'x7' solid surface is too big for my dad's car, otherwise I would've just gotten a huge sheet of lexan or something.
   Nabiul Haque - Saturday, 11/20/10 16:11:03 EST

Hi Guru
How can i get the lead out of old pewter?
Is it possable to refine it by adding antimony ?
I have loads of old pewter "scrap mainly" and wish to remelt it but take the lead out.
I know of the dangers of lead fumes ect but wish to re use
the pewter without the dangers of too much lead in it.
Can you please advise.
Thanks J Bennett
   John Bennett - Saturday, 11/20/10 17:04:18 EST

J Bennett and lead in pewter:

I've asked before and was advised that it is very difficult to purify such alloys.

If safety is your primary concern, then I recommend you sell the materials you have and buy new pewter at ~$14/lb from any number of online suppliers.

If saving money is your primary concern in recycling the old items, then I still recommend you sell and buy new materials. Fuel to melt that scrap is expensive, and whatever chemicals which may be required to purify the alloys will also be expensive.

Who much scrap pewter are we talking about here? How old is it?
   MikeM-OH - Saturday, 11/20/10 17:22:13 EST

MikeM, pewter without lead is no longer pewter. The new pewter is something altogether different from old pewter.
   quenchcrack - Saturday, 11/20/10 19:53:46 EST

Thanks for straightening me out ptree.
For some reason I always thought they were just a straight toggle action but, I guess they would still need to store some momentum (flywheel)
Do you know if there are any videos of one of these machines on the net someware?
   - merl - Saturday, 11/20/10 20:45:52 EST

For the last 3-4 hundred years, "fine pewter" used for flatware was nearly pure tin with up to 1% copper and could contain no lead. When I was supplying art metals we used pure tin with a little copper and antimony.
   - Grant - Saturday, 11/20/10 22:25:49 EST

New pewter vs. old Pewter. Actually there is not a lot of difference. Both are primarily tin with some additions (such as antimony) to make it harder. Some old pewter was relatively low lead and safe to eat off of but not drink out of. Recycled pewter tended to have more lead in it as the folks recycling it also recycled lead and lead/antimony alloys are common. There is probably an historical treatise on this somewhere.

Modern pewter for eating utensils is lead free and alloyed as little as possible.

The lead in old pewter can be considered a hazard when working it but no more so than brasses, bronze and other lead bearing alloys such as free machineing steel. If you overheat it you get fumes, if you grind sand or polish it you get airborne metal dust. In many cases the base metal is more toxic than the lead content. The difference with the lead is that fine particulate on the skin can leach lead and the body absorb it. If you take precautions and have good ventilation it is no more hazardous than other metals. Just don't use it for eating utensils.
   - guru - Saturday, 11/20/10 22:38:49 EST

While there was pewter with lead I was just countering the notion that "pewter without lead is no longer pewter". The pewter Guilds in England and Europe specified a lead-free formulation for pewter since the fifteen-hundreds containing tin and copper and only lead-free formulas are used today. I used to supply tons of pewter to government specs and had a pretty intimate knowledge of the requirements.
   - Grant - Saturday, 11/20/10 23:14:35 EST

Grant, I'm sure you are right. My post was in progress as you posted and I did not intend the cross post. I think the leaded pewters came much later with modern makers making decorative items that did not expect to be used in food service.

The problem with any discussion about such as scrap is that no one really knows WHAT they have unless they have it chemically analyzed. Once mixed scrap is melted then there is no sorting it out. .

Separating out contaminates is very difficult and nigh impossible in some cases. Its not going to happen in a small shop foundry.

   - guru - Saturday, 11/20/10 23:29:07 EST

I agree with you 100%. Especially with stuff coming from all over the world. Heck, it seems the Chinese put lead in everything! lol. I just don't agree that it's not pewter if it doesn't have lead.
   - Grant - Saturday, 11/20/10 23:42:26 EST

What Guru says here was really the point of my post:
"Separating out contaminates is very difficult and nigh impossible in some cases. Its not going to happen in a small shop foundry."

John Bennett mentions recycling and safety... both are goals that often lead small-shop craftsmen into spending much more money than starting with new/clean materials.

You can't KNOW the lead content without expensive professional testing. You can only guess based on volume/weight if you really want to go through the trouble of measuring the volume accurately.

You can't get lead out of an alloy without expensive/dangerous processes.

Either way, safer and cheaper to buy new pewter. Worst case, melt all your scrap into pigs and offer it for sale.
   MikeM-OH - Saturday, 11/20/10 23:56:42 EST

You, got it Mike. Once the lead is in, it's not practical to remove it.
   - Grant - Sunday, 11/21/10 00:16:10 EST

Density: As mike pointed out, density can tell you a little about an alloy but it never tells you what the additional components are. You can tell if the alloy's density is high or low. But what made it high or low? In the case of lead the small percentage that makes an alloy toxic is usually indeterminate via density. Scrap that has lead in it may also have aluminum and the two cancel each other's deviation from the base metal's density. The alloy could appear to be pure via density when in fact it had a lot of unwanted elements in it.

Besides the unknown components, theoretical densities of alloys do not match actual alloys due to the fit of the molecules and the various crystal structures that result from alloying. Given known components of an alloy a theoretical calculation will be very close but not exact. Reversing the calculation is virtually impossible. Believe me, I had this discussion with a NASA metallurgist.

So, despite Archimedes' famous eureka moment, density does not give specific answers, it only presents more questions.
   - guru - Sunday, 11/21/10 00:35:10 EST

Pewter. Don't you know anybody who casts revolver bullets? He would be happy to buy the pewter from you. It hardens up bullet metal a treat. The old southern african big game hunters used to use it a lot. Just trying to think how you explain to the wife that you just downed a brace of Rhinoceroi with her favourite candlestick.
   Philip in china - Sunday, 11/21/10 04:01:59 EST

Grant:

"Once the lead is in, it's not practical to remove it." I'll have to remember that the next time my wife tells me to "get the lead out." (grin).

Just out of curiosity, why were you supplying pewter to government specs? I'm having a hard time thinking of what the government would do with the stuff (or maybe Uncle only provided the specs?).
   Mike BR - Sunday, 11/21/10 09:39:23 EST

Grant, my post was not clear. CLASSIC pewter has lead, modern pewter does not because of toxicity issues. Modern pewter is a tin-based metal containing antimony and copper; originally it was lead and tin. It is suspected of causing wide-spread insanity among the Romans because of lead poisoning.
   quenchcrack - Sunday, 11/21/10 10:10:01 EST

General terms, brass, bronze, stainless, pewter, tool steel, mild steel. . . that is why we now have alloy numbers, standards and performance specs.
   - guru - Sunday, 11/21/10 11:18:18 EST

Ptree - I still have the short leaves out of the leaf spring stack. What do you think of me taking the two shortest and turning them so that their arcs face away from the main (flattened) leaf? Is that going to approximate your setup?
   - Stormcrow - Sunday, 11/21/10 13:56:06 EST

Stormcrow, I have my 2 short leafs de-arced mostly. Grind a nice radius on the ends both ways and you should have it:)
I have been running my hammer about 12 hours a weekend fro the last 4 months. Orders are up, and with 4 in college, life is good.
   ptree - Sunday, 11/21/10 14:10:01 EST

Quenchcrack: Yeah, it's interesting that they seem to have determined that it might be harmful as early as the sixteenth century and came up with formulas without lead for flatware, but still had a formula for hollow ware that contained 2% lead. Then again, maybe they just did that for strength.

Mike: Back in the seventies, I manufactured non-precious casting grain for jewelers and such. The pewter was to government specs, think it might have been the FDA that determined it.
   - grant - nakedanvil - Sunday, 11/21/10 14:10:09 EST

Acme made some lovely upsetters (I think they are american?), Ive done work on an 8" here in the uk, Built about twice as heavy as the equiv rated ajax or national !!!!! I watched the big acme put a spehre on the end of a piece of 8" bar in one hit, came out looking like a white lolly pop :)
   - John N - Sunday, 11/21/10 16:54:21 EST

I am in the process of gather info & material for a power hammer. I have purchased a set of plans from Jerry Allen, Appalachain power hammer. My question is do you know how or have a picture of how an eccentric shaft is mounted to a tire rim as I am going to use a tire to drive my power hammer. Thanks

p.s. I enjoy this web site very much and find it very informative. Keep up the good work.
   carl redmon - Sunday, 11/21/10 18:34:41 EST

John N, have not worked on any ACME upsetters. My experience is 4" to 10" upsetters, 900 ton to 7000 ton mechanical presses by National and Ajax.
Steam hammers Erie 1500 to 25,000# (Double arch stamps to you John I think)
   ptree - Sunday, 11/21/10 18:36:01 EST

Carl redmon, My powerhammer is a rusty style and uses the tire hammer for a clutch. I used the entire rear axle bearing hub assy from a Gran Caravan, and the spare from same. I then used another tireless well for the pivot. I tourched out a portion of the wheel center to get 3 log bolt holes, and welded a nice sized hunk of steel to that. I then drilled and tapped that hunk for a 3/4" shoulder bolt. In this manner i did not have to weld to the compact spare. I also have the easy way to vary the eccentric throw if I desire. I can also just buy another spare if the one I have now wears out. Been running it since about 2005. Been running about 12 hours a weekend for 12 hours or so a weekend for about 4 months and I see little to no evident wear. I have my steel wheel mounted to the motor and it runs on the center of the tire.
   ptree - Sunday, 11/21/10 19:39:18 EST

Sorry, well= wheel and for the repaet. I have spent about 20 hours in the shop this weekend. Tired.
   ptree - Sunday, 11/21/10 19:40:42 EST

Tire Hammers and Wheels: Some folks have had tire wear issues and found that they could not get mini-spares changed AND if you have modified the wheel. . forget it. I found that finding a specific wheel/rim combination was nigh on impossible. That is not a problem if you are building 100% Junkyard style as cheap as possible. BUT, in our case we were building two nearly identical machines (only the anvils are different). If you can't find two that match today, what about 5 years from now when you need to replace the assembly? I recommend standard wheel tire combination. Wheel bolt circles are common enough to find interchangeable wheels and the standard tires can be replaced.

THEREFORE, I think it best to avoid the compact spares and use a standard wheel rim AND not modify it. The standard plans have parts welded to the rims that make it impossible to change the tire IF it was changeable at all.

We modified our rims to suit the design and then modified them again to be able to reposition them in 45° intervals instead of the 90°. After all that I wish we had fabricated a flat belt pulley and could leave the rest behind. . .

The Tire Wear: Now. . the hammers I have heard of with wear problems were heavier hammers, 60 and 100 pounds (ours is a 100 pound machine). IF, you don't pay close attention to how you operate the hammer you can spent a lot of time "riding the clutch" (either getting it started or trying to hold the ram up a short distance) and burn a divot in the tire. Those we have head that wore out tires wore them out near where the hammer is started. This is the same place every time and thus more wear WILL occur there.

We have only run our hammer a couple times and burning the clutch (tire) does not seem to be a problem BUT I can see how it would easily be a problem if one does not pay attention to how they operate the machine. Some folks just aren't that mechanical (including a LOT or modern blacksmiths) and are unintentionally rough on equipment. Its the difference between the person that can't keep an automobile running no matter how much they spend on maintenance and the person that gets 400K out of a vehicle and does no maintenance and almost never has a break down. . . Because they LISTEN to the machine and don't do stupid things. And that may be the problem with tires wearing out.

The mechanics While having the crank attached directly to the driven tire/wheel is simple and direct it causes problems. A couple pillow blocks, a shaft and two auto hubs is cheap and efficient as well but avoids future maintenance issues. There are a variety of ways to attach the crank and they all require a fairly heavy piece of steel to attache it to by welding OR drilling and taping as Ptree did. Welding is simple but it needs to be a good weld and the crank pretty straight and square. The original tire hammer used a self aligning pillow block on the crank which could take some misalignment.

PTree's method uses a shoulder bolt which looks expensive but are precision, hardened, high strength steel. They are a lot cheaper than machined parts. I use them for treadle link pins and the motor pivot. The hard surfaces turn easily in mild steel holes.

SEE Catalog of Junkyard Hammers: Note the Costa Rica Tire Hammer and the NC-JYH.
   - guru - Sunday, 11/21/10 22:36:40 EST

Hi Guru
Thanks for the advise, much of the pewter is old "Very dark in colour" many of the items are old tankards and such, about 28 pounds in weight, "maybe someone wants a flywheel!" now i know i'll buy in like sugested. safer and cheaper in the long run. Thanks again Guys
   John Bennett - Monday, 11/22/10 04:10:48 EST

No problem with a little lead; the dain bramage is minimal.

What were we talking about?


;-)
   Bruce Blackistone (Atli) - Monday, 11/22/10 09:08:02 EST

I seem to find that Sherri's suggestions are explosive, can you help in this regard?
   garry - Monday, 11/22/10 09:56:09 EST

Steve Gensheimer, sent me a note and says he spoke to Rich Waugh and he is recovering and in good spirits. But he still has a way to go. Keep him and his family in your thoughts.
   - guru - Monday, 11/22/10 11:12:17 EST

Garry, what ARE you talking about?
   - guru - Monday, 11/22/10 11:13:05 EST

Uses for Leaded Pewter Lots of art work, chess pieces, book ends, heavy jewelery (such as belt buckles) and other non-food related uses are safe. As I mentioned, the lead in the fumes is minor compared to other metal fumes. In fact, the reason pewter is popular is the low melting point. The greatly reduces any lead fumes.

The dark color is normal on old pewter. Tin DOES oxidize over time and turns black. Even old pure tin plated cans blacken. Those used for acidic contents are lacquered to prevent the acid from attacking the tin. It does eventually, thus "shelf life".

Artistically many pewter items are blackened with acid OR paint and the highlights polished to produce some depth of color and texture then the whole is stabilized with clear lacquer.
   - guru - Monday, 11/22/10 11:20:22 EST

there isn't a sheri's den so therefore the question has to go to the guru's den. when using her bean recipe, what suggestions are there for internal combustion after eating the beans? humorous, yes, but serious. this is from the health section. thank you.
   garry - Monday, 11/22/10 14:48:10 EST

Beans, beans in the pot: Gary, Presoaking or parboiling and dumping the water helps. I think I forgot to include the addition of one potato in the beans. . . That seems to help, sometimes not. Each batch seems to be a bit different and I think the biggest variable is the soaking time. I've never tried Beano. . .

Dr. Fuhrman says its the inability of your body to digest certain things and eventually the problem goes away. However, I do not notice a different after nearly 6 months. . .

I do notice a LOT of other differences from the bean and vegetable rich nutritarian diet. I am generally healthier, many aches and pains have gone away, I can breathe better, my circulation seems better, I sleep better and snore less (I'm told). A lot of this is related to losing weight and getting more exercise but I think it is much more than that.
   - guru - Monday, 11/22/10 16:17:13 EST

Hi, we are looking for CI25 cast frames for paper mill.

not sure what is the difference between cast grey iron or cast iron. is it the same? can some one guide us please.
   Partha Kollu - Monday, 11/22/10 22:43:48 EST

I am attempting to identify a late 19th century/early 20th centry anvil. Have been in contact with Mr. Ken Scharabock who suggests that it may be of early Australian manufacture since he cannot identify the maker's mark. Can you help identify if I email pictures of the mark as wellas the anvil--If so, do can I email pictures directly or should I go through Photobucket--
Regards--
Gordon Rich
   Gordon Rich - Monday, 11/22/10 23:08:08 EST

Cast Iron: Partha, CI25 is probably ASTM grade 25 cast iron. See our FAQ Cast Iron Properties. Cast iron varies from grade 20 to grade 60 dependent on the carbon content and other constituents.

Cast iron is a general non-specific term that means almost nothing from a metallurgical/engineering standpoint. Grey iron is a little more specific but is still a general term as there are many grades. The ASTM grades are performance based and specific.
   - guru - Monday, 11/22/10 23:24:42 EST

Do any resources exist on regional indoor and outdoor design temperatures for air conditioning systems? I'm also looking for general cycle temperatures of ice making systems.

Searching keeps leading me to this illusive "Manual J", but it doesn't seem to be available in electronic format. My university has a bunch of the recent ASHRAE manuals for the latter half of this decade, but they aren't of any help... to me any ways. I need some kind of starting point for designing ideal cycles; the peak loads were already given to me.
   Nabiul Haque - Monday, 11/22/10 23:25:29 EST

Gordon, email the anvil photos to me.
   - guru - Monday, 11/22/10 23:28:20 EST

Nabiul, I had good luck using the terms in google "heat pump operating limits". I also had luck with "HVAC operating limits". I did not read the articles closely but they seemed to have the information you need.

Otherwise this is out of my area of expertise.
   - guru - Monday, 11/22/10 23:36:55 EST

Rarely do I get to turn an idea into a working reality so quickly... and it would not have happened without the help of Guru and so many others here.

Behold, my Coining Press: http://marco-borromei.com/c/c.htm

I dropped off the cardboard pattern at the steel shop this morning around 7am. The promised wednesday, but had it cut 2 hours later. Strangely, although my pattern had 1" radii on the inside corners, they cut it pretty straight. :( Got a discount for that mistake. :) The "donut hole" became the jack table, and scraps of 3/8x4 became the legs and table braces [not visible]. The frame is 3/4" thick plate, narrowed considerably from my initial drawing to be stronger. There's just enough width for the press; enough height for 6" of tooling and work space.

It took 2 hours of grinding, preheat, welding, and painting to assemble. The die holder and first test coin die were already done.

The first coin took about 15 seconds to press. I went on a 5 min tangent modifying an old socket to fit the release valve for quicker operation. I'll replace the thin handle with something stronger too, and bolt down the jack.

Bottom line, it works. I was stunned to see how deep those coins presses with so little effort. Every scratch on the die is visible on the coin face. Now I can spend the long arthritic winter nights engraving coin dies secure in the knowledge that I can mint them any time.

Not pictured are the simple steel punched I made to punch out the planchets. I'll get pics of those when the holiday housework is done.

thanks again!
   - MikeM-OH - Monday, 11/22/10 23:55:28 EST

Unfortunately I'm not having the same luck with those terms.

I'm trying to find what could be considered an official or academic source. Doing a pretend design project; one of those things that are completely based on the opposite of reality. Who's going to pay a fortune to have my ideal AC cycle manufactured in a one-off quantitiy?
   Nabiul Haque - Tuesday, 11/23/10 00:09:59 EST

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