Blacksmithing and Metalworking Q&A : anvilfire Guru page : Jan 1

WELCOME to the anvilfire Guru's Den - V. 3.3

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 January 1 - 7, 2008 on the Guru's Den

[ THE - GURUS | ABOUT THIS PAGE | Getting Started in Blacksmithing ]

2008, 10th Anniversary of Anvilfire.com:

This is the beginning of the 11th calendar year of anvilfire.com. Conceived in December 1997, registered in February 1998 and launched in March 1998. We've had over 11,214,590 visits since adding counters in June of 1998. Our 10th anniverssary will be celebrated in April 2008!

Happy NEW year!

- guru - Tuesday, 01/01/08 00:57:23 EST

Tim: You can go to a brick supplier and pick up a standard fireplace masonry brick for a couple of bucks. Places which sell wood burning indoor stoves should have similar brick, but only half as tall. One disadvantage to these clay-based bricks is they stay hot for quite a while after forge is shut down.

Ken Scharabok (Poor Boy Blacksmith Tools) - Tuesday, 01/01/08 06:28:42 EST

Wood stove installation. Here's one for the wood burners out there. I'm putting a class a insulated pipe through a brick wall and I'm wondering if I really need to use a thimble to give it 2" clearance. If possible i'd like to be making a 8" hole instead of an 11" in the wall. Does anyone have thoughts on this?

- andy - Tuesday, 01/01/08 10:32:19 EST

Guru, congratulations on the success of Anvilfire. It is a real work of art!

quenchcrack - Tuesday, 01/01/08 10:40:19 EST

Guru, Thank you for all your years of service to the blacksmithing community. Anvilfire is a valuable recourse to us all.

Tim - Tuesday, 01/01/08 10:57:25 EST

Yeah Jock, THANKS. Have very much appreciated this site over the years. Happy New Year.

- Ten Hammers - Tuesday, 01/01/08 11:40:28 EST

Square tubing sizes. I need some 3/4" sq tubing for a table I am making and it needs to be heavy enough to weld and blend with 3/4" solid stock. The stuff at the small local steel yard (Empire in Santa Fe) is very thin walled, less than 1/16" but they will order for me from Albuquerque. How can I find out what standard thickness are availabe in sq steel tubing and what they are called?
Thank you

This site is indeed a wonderful resource and I have benefited from it enormously. Not only is the site itself a tremendous piece of work but the presence of so many knowledgeable and helpful people, gurus, members and visitors, greatly enhances its usefulness. I am constantly amazed at the range and depth of knowledge that shows itself in the posts here.

If you find yourself using anvilfire more than occaisonally, please consider a paid membership. It is very little money and this site *needs* support to keep going.

Happy New Year

adam - Tuesday, 01/01/08 12:02:24 EST

adam: I use 1" tubing on a regular basis. It comes in thin wall (1/16") and thick wall (1/8"). It is readily available at my steel supplier. Problem with mating it with solid is solid has square corners while the tubing has rounded corners.

Ken Scharabok (Poor Boy Blacksmith Tools) - Tuesday, 01/01/08 12:34:51 EST

Steven Johnson:

By far the most comprehensive book on rifle-forging how-to is "Notes from a Small Iowa Rifleshop" by Steve Bookout. It's a thin spiralbound paperback, but it includes patterns. Also see "Re-Creating the American Flintlock Longrifle" by Peter A. Alexander, William Buchele, and Goerge Shumway.

Alan-L - Tuesday, 01/01/08 12:43:39 EST

Structural Steel Tubing: Adam, Your steel supplier will be able to tell you what is available. Ask for a catalog. While there are many standard shapes what you want to know is what they normally inventory. The standard reference for these kinds of things is the AISC Steel Construction Manual.

3/4" square tubing comes in wall thicknesses of 20ga, 18ga, 1/6", 16ga (.065), 14ga (.083) and 11ga (.120).

- guru - Tuesday, 01/01/08 14:53:44 EST

Pipe Through Wall: If the wall is all masonry then the pipe needs just enough clearance for installation and expansion. If there is a wood layer there should be clearance and most codes call for 2" of rock wool (Kaowool).

- guru - Tuesday, 01/01/08 14:55:21 EST

hmmm.... rounded corners! hadnt considered that - perhaps I should weld 3/4" angle iron together to make a tube.

adam - Tuesday, 01/01/08 15:37:10 EST

Adam, Then you have sharp and flat or round OR you have to build them up to sharp. Much more work than rounding the corners on the solid IF they are sharp. Good hot roll has a radius on the corners. The two different materials will also have different surface textures (if that is important). AND grinding is a much different texture than as rolled.

- guru - Tuesday, 01/01/08 17:17:49 EST

Adam-something else to consider is tubing dimensions would be O.D.(outside dimension). When you are calculating stock thickness this will affect the I.D.. 1 inch square tubing with 1/16 thick walls would have and I.D. of 7/8 inches were as a tube with 1/8 thick walls would have an I.D. of 3/4 inch.

Tim - Tuesday, 01/01/08 22:04:12 EST

Adam and all,

Sometimes I forge weld a sharp cornered square solid into tubular square. I've done it with lighting fixtures where the electric cord can run in the tube, but the termination of the tube becomes a solid decoration, a scroll or something of the sort. I don't use a scarf. I insert the solid into the hot tube for a proportionate distance, usually 1/2" to 1" and take a SLOW rising heat. It should be a tight fit. It usually takes me several heats to get the two to blend nicely. I use light and moderate blows. Hitting too hard causes the tube to become oversized, especially at the beginning.

Frank Turley - Tuesday, 01/01/08 22:24:59 EST

Tubing: I think I will go with solid stock after all. I am making a coffee table with cabriole legs. The legs are forged out of 3/4" sq and I was thinking to make the rails out of sq tubing because of the weight but after the comments here, I think solid is best and it wont be that heavy. The rails are hidden under the table top so appearance is not critical but still, an obvious mismatch between the two kinds of stock would be cheesy. I would like to do the weld that Frank has described but not on this project. Firstly the legs are already formed which makes handling the assembly awkward and secondly I am not confident I can get both sides to come out the same length. So its going to be Mr Stick

adam - Wednesday, 01/02/08 10:39:17 EST

Color case hardening kits from Brownells: http://preview.tinyurl.com/ysnd5n

On a different note: I'm building a small cart similar to a welding cart, with legs at the front and wheels at the back. I'd like to add folding/retractable legs that can lift the wheels off the ground when needed, then stow away neatly when they're not needed. I can think of a number of ways to do this, but none are quite as user-friendly as I'd like. ideally I'd like the legs to deploy and lock in place via a cam/linkage arrangement operated by a foot pedal or lever. Can anyone point me to a good model of the sort of thing I'm looking for? I spent several hours yesterday making drawings and little models of various linkages. Some would work, but none of them are as slick as I'd like. I'm feeling pretty thick-headed at the moment.

Matt B - Wednesday, 01/02/08 11:39:28 EST

Matt, I have seen equipment tables such as for a table saw with a center retractable wheel (caster). It was simply mounted on a lever that was pushed down to lift the table and then locked. The table could then be rolled anywhere then lowered back onto its legs. It only lifted about an inch and rolling was not fast and smooth but roll it did. Very handy for tools and or machines that you do not move often but would need help otherwise.

- guru - Wednesday, 01/02/08 11:51:31 EST

Back from the holidays!

Rubble: industrial coke makes a nice rubble and scavanges O2 to boot, though the "sand" ashes might be a problem with borax glue. I would suggest a cheap stainless steel tray to hold the rubble/flux drips and consider it a consumable. IIRC a stainless tray with a layer of kitty litter was suggested as a flux capture device.

Considering that I have cousins on the pro-rodeo circuit and that anybody from a small town in NW AR that has been there since say the 1960's is related to me. I guess I can make some redneck and hillbilly claims. Now my great grandmother was an old no school'd hillbilly and I'm proud to have known her and that her genes run in me!

Thomas

Thomas P - Wednesday, 01/02/08 11:52:41 EST

I did consider making the wheels retractable instead of the legs. I could do either one -- once I figure out the mechanism!

Matt B - Wednesday, 01/02/08 12:12:27 EST

Matt,

I made a cart with retractable wheels one time. I mounted the wheels on a subframe that was hinged/pivoted to the cart body. The axis of the pivot was perpendicular to the long axis of the cart (parallel to the axle the wheels were on). I put a socket on one side the subframe that I could slide a lever into, and used the lever to rotate the subframe on the pivot so the wheels extended. I put a pin on the cart body that I could hook the lever under once the wheels were down.

Mike BR - Wednesday, 01/02/08 12:23:38 EST

Matt B. One solution is an over-center mechanism. Look at the hold down on an apron brake. The wheels can be allowed to touch the ground in the up position, but will only bear weight when in the down position. No pins this way.

John Christiansen - Wednesday, 01/02/08 12:58:27 EST

Mike,

On your design, what kept the wheels up when they weren't in use?

John,

Yes, an over-center mechanism was what I was trying to achieve with all my little models and drawings yesterday. I just didn't know what it was called. Now I have a bunch of examples to look at. Thanks.

Matt B - Wednesday, 01/02/08 13:45:37 EST

Matt,

Nothing. They just rested on the floor with no weight on them (other than their own and that of one end of the subframe). I guess it would have been easy enough to add a pin to hold them up, but I never saw the need.

Mike BR - Wednesday, 01/02/08 14:22:13 EST

greetings i have been asked to make some spiked toothed harrow points....they are diamond shaped spikes about six inches long and half inch square that has been parallelogramed and i was wondering if anybody knew the proper steel and hardening for theese spikes maybe 1080 tempered to blue? thanks

coolhand - Wednesday, 01/02/08 16:04:16 EST

This may be a little off topic but
I have a shop ventilation question

My shop is my garage it has bedrooms above. The shop is 25' long and 12' wide with a grage doon at one end and a window at the other. I was wondering what I should use for forge and welding ventilation. I would perfer a home made soultion as money is kinda tight. But saftey is a concern because of the whole bedroom situation. Any feed back would be nice.
Thankyou for your time
Glen Saamanen

Glen Saamanen - Wednesday, 01/02/08 16:33:13 EST

I am doing research for the restoration of a period forge (c.1850) and trying to determine whether a treadle hammer of some kind may have been in use anytime around this period. I have seen patent drawings, but never a photograph. Can you help me find out what kind of heavy hammer might have been in use (other than shaft driven by steam or water) anytime in the 19th century?

Peter Hirst
Orleans, Massachusetts

Peter Hirst - Wednesday, 01/02/08 17:30:12 EST

Glen Saamanen,
You don't mention what fuel the forge is to burn. I will assume gas/propane, since if coal I would assume that a stack would be required simply to see:)
You also don't mention where the forge is located in relation to the windows and door.

Without this info I can offer the following. A good high quality Carbon Monoxide monitor/alarm can be had at the big box stores for about $40.00. i would NOT even contemplate using a forge in a shop with living quarters attached or overhead without a CO alarm in BOTH the shop and the living quarters. If you have fuel burning appliances in the living quarters like a furnace, space heater, or water heater you should already have the co alarm anyway. Note that carbon Monoxide is slightly heavier than air, but if very hot from the forge will rise, then settle back when it cools.
If you have the alarms, and the shop door and window are open, with cross draft naturally flowing from a breeze you should be OK. A natural breeze is not often going to blow when you need it, in the direction you need it, so a window fan may be needed.

ptree - Wednesday, 01/02/08 18:32:43 EST

Peter, you mean besides the 2-5 assistants with sledgehammers?

Historically a single person blacksmith shop was just about as common as an operating room in a modern hospital with only a surgeon present.

You might search on "oliver" as being a more common term for a type of treadle hammer; but a couple of helpers with sledges was the common method where there were not water driven tilthammers (and they were generally used only for large forgings as there was a lot of capital and maintenance expense tied up in a mill!)

The use of something other than "help" is much more of an outlier if you are working towards a living history grade presentation.

Thomas

Thomas P - Wednesday, 01/02/08 18:42:51 EST

I forgot to mention that towards the end of the 19th century the mechanical powerhammer became in general use. the book "Pounding out the Profits" gives a good survey of the various types with lots of great patent information too! These were often frun from a lineshaft that may be powered by an engine instead of a motor.

Thomas

Thomas

Thomas P - Wednesday, 01/02/08 18:46:30 EST

Coolhand: Harrow teeth/spikes have been around for a long time. I suspect at least the earliest metal ones were wrought iron - wood before then). They would be replaced as they wore down. You could get a lot of teeth out of a coil of 5/8" 5160 vehicle spring. Just forge the round to square. Check into quenching entire tooth in used crankcase oil a couple at a time, then allow oil to completely cool down before anohter couple of them.

Ken Scharabok (Poor Boy Blacksmith Tools) - Wednesday, 01/02/08 19:26:17 EST

Glen-- Move the forge outdoors. Even with the door and window wide open the exhaust will linger and cause bad headaches. At least mine did inside a similar-size shop, Even outdoors, the exhaust will still hang around. I think the fire code bans keeping a bottle indoors, anyway.

Miles Undercut - Wednesday, 01/02/08 21:12:55 EST

Matt B-- MSC has a variety of step-on floor locks for fixing wheeled equipment in position. Look in their vast catalog amongst (love them Brit words, love 'em!) the myriad casters.

Miles Undercut - Wednesday, 01/02/08 21:30:27 EST

Glen: I have an old ventilator fan mounted in place of the top sash in a basment window. It is a pretty powerfull fan. The trick is in limiting the intake area so that any air flow is from the house into the shop area, not the other way around. This works fine for welding, particulary good for TIG and MIG as they make less smoke. With regards to a gas forge, You might need to take a lot more care than this, I think I would if possible build a drywall enclosure the width of the window and from the floor to the top of the window [with the fan mounted in the top sash] high and put the forge in this enclosure. Some heat shielding might be needed depending on the forge. Use the CO detectors in the shop area and in the rooms above.

- Dave Boyer - Wednesday, 01/02/08 22:54:30 EST

Peter
On Youtube there is some film of very early 20th century blacksmithing in a section on chain and anchor making. One of the chain maker smiths uses a treadle hammer. I think it was 1904 which I realise is later than you want but it looks as if it had been there for ever even then!

- philip in china - Wednesday, 01/02/08 23:25:22 EST

Modern interpretation of old treadle hammer: http://www.beautifuliron.com/old.htm

Old photo of an Oliver: http://www.sedgleymanor.com/trades/nailmakers2.html

Miles, thanks for the tip. That's exactly the sort of mechanism I was looking for.

Matt B - Thursday, 01/03/08 00:17:23 EST

I operate a propane forge in my 2-car garage. I have windows in the doors that open. What I do is open the windows furthest away from each other and have a pedestal fan, a basic Walmart type, blow out one of the windows. The most important part, as others mentioned, is the CO monitor. I notice the CO start rising when the forge is warming up, so I turn the fan on. But once the forge is hot, I can turn off the fan and the CO stays at 0.

In the summer, all the doors are open and I usually have the fan blowing in.

My propane comes from my house tanks outside. I believe Miles is correct in that the National Fire Code doesn't allow indoor tanks. I've seen indoor tanks in many shops, though, but I would talk to the other residents of the house about that one.

- Marc - Thursday, 01/03/08 07:46:50 EST

I didn't know propane dealers would allow their gas to come indoors at a pressure sufficient to run a forge. 11wci, max, right?

Miles Undercut - Thursday, 01/03/08 11:36:23 EST

Ken,

I finally succeed doing a forge weld but now as a drw my stock the weld comes apart.

I tried to forge weld 4 rod of 5/16 together to do the Basket twist handle on a Fire pocker. I have succeded to done one end by forge welding the forge twist to a 1/2 Square stock but when I tried to forge weld the other end to drow to make a proper handle my forger weld comes apart as I am drawing the stock

Thank you frank, part of my problem is that I was hitting the metal to hard to start with. However as I mentioned abouve the minute that i try to draw any forger weld section it wants to come apart.

Thanks for all your help

Dan

Dan - Thursday, 01/03/08 16:22:49 EST

Living Space over Forge Shop I have been in this situation twice. Generally it doesn't work unless you have very tight construction preventing smoke infiltration AND very good forced ventilation. Venting should always be higher than the living space if possible. Otherwise fumes and CO can infiltrate the living space.

The reason the venting should be higher than the living space is that you can NEVER predict what wind or breezes will do. Exhaust from common furnaces have been known to kill people when a slight but unusual breeze combined with an inversion layer filled a home with the fumes. While this is rare it DOES happen. Breezes blowing steadily in a bad direction IS fairly common.

Because of infiltration a CO meter/alarm in the living space is as important as in the shop.

- guru - Thursday, 01/03/08 17:02:42 EST

Propane can be delivered at up to 5psi. But even at the lower NG pressure, all you need is piping big enough to deliver the BTUs/hr you want. You'll also need a blower, as that pressure isn't enough to get the velocity required for an aspirated burner. But I know several smiths who run off NG street pressure at 11wci and do just fine with a blown burner.

--Marc

- Marc - Thursday, 01/03/08 17:55:43 EST

ok...it's time...i need a forge that i can weld in. it's gongi to be spesifically for welding up damascus billets. so it doesn't needa very large intirior volume. but it has to get HOTT and be able to withstand the flux.
could anyone help me out on this?

Jake

- jake - Thursday, 01/03/08 18:24:22 EST

Another option for a gas forge in an attached garage might be a powered hood with the exhaust ducted through the window (or out the door).

Mike BR - Thursday, 01/03/08 18:36:55 EST

Dan,

Draw it at a welding heat. In fact, you can take a half dozen welding heats or so in the same area without damaging the metal...as long as the heats are not super bright sparking heats. It is best to forge weld mild steel at sweating heats (no sparks) or at welding heats that show only a few incipient sparks, NOT a big shower of sparks.

Frank Turley - Thursday, 01/03/08 19:22:42 EST

what do y'all think about the "pro-forge" for a working farrier. i'm lookngi at it and it seems like a grand forge to purchace. i am a new farrier trying to build my client base and reputation.

John

- john - Thursday, 01/03/08 19:58:03 EST

Frank,

I am back in the forge tomorrow morning first thing to try to make this work.

You might be right, I might have been a bit impatient and try to rush the draw, I will try to slow things down and see what happen

I really appreciate your time and effort to help me

Dan

Dan - Thursday, 01/03/08 20:04:09 EST

I am researchng the uses of beeswax and came across a reference to armour. It was used as a resist after a design was applied to the metal.

I was wondering if anyone has heard of this. Also does anyone know of any books that might also reference this so that I can do more research? This is for an SCA paper, not homework.

Sarah - Thursday, 01/03/08 20:05:36 EST

Hi Sarah,

I know that very few people these days use Hydrofluoric acid to etch Glass but I know that the practice is common in England. Beeswax has been use extensively as a resist by the glass artist in Europe and some in the USA.

Either google Hydrofuloric acid use for etching glass or you can always try to post the question on www.warmglass.com. That is the equivalent of anvilfire.com for the glass artist.

I suspect that the beeswax was used as a resist against acid back then on armour as well. Steel and glass does react pretty much the same to heat

Good luck

Dan

Dan - Thursday, 01/03/08 21:18:09 EST

John: Our local steam & gas engine club hosts a farrier competition as part of Our "Black Smith Days" event. Most of the farriers used the larger "Forgemaster" or "NC Tools" forges, about equally split. A few used others, including home built ones. Interestingly, one of the advanced shoes required forge welding, not everybody made those. Who makes "Pro-Forge" and where can We see pictures of one?

- Dave Boyer - Thursday, 01/03/08 22:25:10 EST

Jack: Be sure to take a look at both Diamondback's and Chili Forge's propane units. Both are designed for forge welding.

Ken Scharabok (Poor Boy Blacksmith Tools) - Friday, 01/04/08 02:55:15 EST

Sarah,

Oppi Untracht gives a good discussion of metal etching in his book, "Metal Techniques for Craftsmen". Beeswax was and still is used and applied melted to warmed, clean, degreased metal with a brush to get an even flow. Untracht says that etching for decoration was not used until the 15th Century, and was then used often on armour and weapons. Untracht is specific about using resists such as beeswax, parafin, and asphaltum. He gives formulas for acids to be used.

Frank Turley - Friday, 01/04/08 08:28:58 EST

i know they have them at pieh tool co. thats the only place i have found then.

John

- john - Friday, 01/04/08 08:48:44 EST

Jake are you looking to build or buy? Makes a difference WRT "help".

Sarah, I can look through a number of books I have on armour; but it will probably be Monday before I have computer access. How time dependent is this? I particularly want to go through Alan Williams' book on the history of technology of the Greenwich Armoury to see if he covers embellishment of armour in it. Also the Hausbuchs that show various crafts in the renaissance as I know that an armour polisher was listed as a seperate craft.

Thomas, SKA Master Wilelm the smith

Thomas P - Friday, 01/04/08 12:51:43 EST

I'm thinking of building a ring roller and wondering who has had luck with this. I don't have access to a lathe. So I would like to find substitute for the rollers. Any advice?

Mark H - Friday, 01/04/08 13:04:26 EST

i'm looknig to make one if possible. i have quite a bit of fabrication experience but i don't have access to equipment and machinery. but yes i would l ike to make it

JAke

- JAke - Friday, 01/04/08 13:34:19 EST

maybe one like the hypona forge. i can't find the link but it looked good.

JAke

- JAke - Friday, 01/04/08 13:53:58 EST

It is not very time sensitive. I will be working on this project for a while. I can wait until Monday. :)

Thanks!
Sarah

- Sarah - Friday, 01/04/08 17:31:07 EST

Mostly I use my propane forge furnace to heat mild steel but I also forge naval brass and silicon bronze in the same furnace. From time to time I will lose concentration and melt big pieces of bronze in the furnace. I scrape the molten bronze out of the furnace as best I can but when I return to forging steel at higher heats green flames coming from the doors for weeks afterwards show me that copper and zinc are still vaporizing. How concerned do I need to be about this. Is there a "seat of the pants" mehtod for determining how much toxicity I might be exposing myself and people in my shop to? I have installed a blower powered ventilation hood over the furnace but still think I smell and taste the fumes slightly. What do other blacksmiths do about this problem? Is it best to have a designated bronze furnace? It is cost prohibitive to rebuild the forge after each heating accident. Are there health concerns from these fumes at lower concentrations than than those that cause metal fume fever? I would appreciate any thoughts or advice. I sure do like forging bronze. Christopher

Christopher Thomson - Friday, 01/04/08 17:37:46 EST

Chris-- There is a fabulous metal artist, a sculptor, Bill Weaver, in the Santa Fe phone book. He does a lot of work in bronze at Shidoni and his private shop in Tesuque/Chupadero/Rio en Medio, unknow just where, and has been generous with advice to me in the past. Try him for guidance re; safety with bronze.

Miles Undercut - Friday, 01/04/08 17:58:15 EST

Chris,
Most of the heavy metals are a cumulative issue, ie they build up in the body over time even at low exposures. Chrome, cad, nickle, chrome mercury, and zinc are all in this series and are a threat. Metal fume fever and toxic buildup are two different maladys.
If i had the space, I would build up an optimized forge for the bronze. Think of it as getting a better forge for bronze:)

ptree - Friday, 01/04/08 18:14:19 EST

Mark H, I just posted an answer to this Question on ArtMetal under Make a ring roller without a lathe.

John Christiansen - Friday, 01/04/08 18:23:19 EST

Christopher Thomson,

I'd sincerely suggest you build a dedicated gas forge for the non-ferrous metals. Not only will you avoid toxicity from accumulated vaporized metals in your system, you won't be ruining work so ofen if you build a forge that can be controlled to a better temperature for forging bronze and brasses.

I forge a fair amount of silicon bronze and find that my gas forge, once stabilized after initial run-up, can hold just the right temperature for silicon bronze with one burner running just above idle. I haven't melted anything since I learned that. If I wind up doing a lot more bronze, I'll build a dedicated forge with a larger volume that can run at the right heat on two small burners. The convenience would be worth it to me.

vicopper - Friday, 01/04/08 19:16:56 EST

Guru & All,
I just want to wish you all a Happy New Year and thank you profusely for the info I've gleaned off your posts and input on this site. I started 4 years ago as an ex-jeweler, know-nothing smith, and now I'm officially a know-something smith!! Too Cool! Here's to many more years of this excellent site and the people who populate it !!!! Thanks.

Roland (Thumper) - Friday, 01/04/08 21:30:05 EST

Hello guru,
Yeah! my new swage block has just arrived. Do you have any suggestions for finnishing it up? I am open to suggestions on cleaning up cast iron. Thanks Tim

Tim - Friday, 01/04/08 21:34:54 EST

Anvil design. I am trying not to get too fixated on this subject but... what is the advantage of a double bick anvil? I am trying to source an anvil for my place in Bulgaria and have had a very special offer made on a new 254 Kg double bick. Try as I might I can't hammer with both hands at once so what is the purpose please?

- philip in china - Saturday, 01/05/08 05:17:14 EST

Double bick. I have a London pattern anvil and I wish I had a square bick. When forging a shoulder on a piece whose shape doesnt allow it to be laid flat on the anvil face a square horn would let me get in there easily. The standard technique on a London pattern is to lay the work across a corner but I have never found this satisfactory. With a square bick one just has more forming shapes built into the anvil and less often needs a special hardy tool.

Zinc: it is my understanding that zinc is not a heavy metal in that it is absorbed fairly rapidly by the body and also eliminated in a few months, unlike, say lead which is absorbed very slowly but never eliminated

adam - Saturday, 01/05/08 08:28:28 EST

Re. zinc actually a small amount is required by the body. Some bodybuilders and impotent men take zinc tablets as it is supposed to stimulate testosterone production.

Thanks for the help re the double bick.

- philip in china - Saturday, 01/05/08 08:42:05 EST

Hello I would like to know if it is possible to burn anthracite coal in a forge. It is very hard to get smithing coal and i have to travel a long way to get it. are there any big changes between burning bitumanous coal and anthracite coal??

Bob - Saturday, 01/05/08 09:26:18 EST

Zinc, like many metals in the RIGHT amount is needed for health. Too much causes health problems though. I erred in including zinc in the heavy metals though. My Bad.

Ptree - Saturday, 01/05/08 09:36:25 EST

Double bick anvil:

Now that I have one, a Nimba Gladiator, I would never go back to a London Pattern. The tapered square bick is wonderful for those short shoulders as Adam mentioned, and punching in tight places, working small sections, etc. I get far more use out of the flat bick than the round one, in fact. Because it tapers in thickness as well, in many cases it acts as a shelf would, allowing me to work fork tines and such without a hardy tool. Wonderful anvil!

vicopper - Saturday, 01/05/08 09:44:29 EST

The quadrilateral horn or bick is one of those things that requires thought to come up with it's uses...and it hurts. As one of my mentors told me, "When you need it, you need it!"

One use that I remember as a farrier, is that it helps to level a shoe that has two side clips projecting from the web of the shoe. No matter what size shoe, one can find a place where the clips overhang either side of the bick. With the London pattern, we would drop one clip into the hardie hole and juggle the shoe around so the other clip was overhanging the anvil edge; it was more of a bother.

Another use is where you have a small right angled return, "hook like". You can work it near the tip of the bick, whereas the thick heel of the London pattern is obstructive.

For bends on small pieces of stock, sometimes the tongs impede the work on a London anvil. The Continental bick allows you to move to an appropriate place for the bend. This, in turn, relates to Adam's response, where it is difficult to shoulder on a London pattern for similar reasons.

I've made lots of branding irons, and in making letters and figures, the Continental bick is more useful than the thick heel on the London. Furthermore, I've often had to work over my smaller bickern the get the work to behave.

Frank Turley - Saturday, 01/05/08 09:57:19 EST

John,...farriers forge

I'm a full time farrier and I'm currently using the NC wisper delux in the truck. It works ok for me and I can weld bar shoes or whatever else I need to do...though I have a coal/charcoal forge in the shop.

I'm hearing lots of good things about the forgemaster forges but I see guys with all kinds of forges including little one burner jobs.

I'm not familiar with the pro-forge but, as always, it depends what you're going to be doing with it. What kind of work are you going to be doing? Do you need something big enough for draft shoes? Are you going to be making lots of shoes in it or just do a little hot fitting? A lot of guys use a little forge in the truck but have a bigger one in the shop.

Mike Ferrara - Saturday, 01/05/08 10:54:29 EST

Damascus Forge: Jake you do not need nearly the high temperatures required for welding mild steel but you do need high BTU. High carbon steels weld at much lower temperatures than low and the billet is generally welded at the lowest temperature alloy's welding temp. Most of the bladesmiths use blown forges because they are more adjustable and push more BTU's through a given volume.

- guru - Saturday, 01/05/08 10:55:14 EST

Metals and Health: The form the metals take is very important. They are usually compounds and in very small or even trace amounts. Most pure or alloyed metals in their metallic form are toxic. Their are some exceptions such as iron and gold. But while the body needs some copper all metallic copper and its alloys are toxic if ingested or inhaled.

The popular usage of faux health information that says you need such and such element in your diet is very bad use of language and spreads bad information. Certain compounds that contain metals are highly toxic while others are relatively harmless. Those needed in one's diet are very specific but are never the metallic form.

So, if you are going to talk about one's body needing this or that, be specific. Otherwise you are just spreading misinformation and faux science. We get enough of that every day without having it on a metals forum.

- guru - Saturday, 01/05/08 11:23:45 EST

- guru - Saturday, 01/05/08 11:54:41 EST

can anyone tell me the diffrance between the forging capabilities of bitumanous coal vs anthracite coal?? thanks

Robert - Saturday, 01/05/08 13:17:42 EST

Rich, A Nimba Gladiator???? . I might charter a Huey and fly over the island with a scrapyard magnet some night....

adam - Saturday, 01/05/08 14:21:30 EST

Robert... Rumor has it that some blacksmiths do use Anthracite coal. I've read that it take more fire tending. It needs more continous air flow air to continue to burn and maintain forging temperatures. Bitumanous is easier. I expect however, with an electric blower, it wouldn't be that hard to manage. I'm sure others will weigh in with their experiences....

- djhammerd - Saturday, 01/05/08 16:12:05 EST

hey thanks i think i will get a 40 pound bag at a nearby store and try it. it is only like 5 bucks so it cant hurt

Robert - Saturday, 01/05/08 16:39:06 EST

Adam,

I couldn't help myself; I got for half price on Ebay, in mint condition. Be a fool to pass that up, no? You're welcome to visit it, of course.

vicopper - Saturday, 01/05/08 16:59:31 EST

Is the only difference between a 5 and 7.5 hp ingersol compressor the motor? Could you safely swap the motor and improve performance/output?

brian robertson - Saturday, 01/05/08 18:33:49 EST

Brian,

I know that on the IR models with the T-30 compressor head, the head is the same. There is likely a difference in the motor sheave though, or you couldn't get any addiitonal flow from the same displacement pump. With a change in the motor sheave, it may necessitate an additional belt to handle the start-up resistance, but I don't know. That would be my best guess, though.

vicopper - Saturday, 01/05/08 19:13:59 EST

Anthracite: Generally it is difficult to use but it works (as all fuels can be made to work). Fires are maintained with continuous air or they go out. That means no bellows or hand cranks unless you have slave labor. Fires are also deeper and the heat tends to burn out firepots.

Anthracite does not have the volatiles that bituminous does so it does not melt and form larger pieces as it cokes. It also does not coke well tending to burn rather than coke.

It is very different than the preferred coal for smithing and the fire maintenance is completely different as well. Smiths that have no other choice use it and learn how to maintain a working fire. But this is something you will have to experiment with on your own.

- guru - Sunday, 01/06/08 00:14:16 EST

Melting steel in a gas forge:

I know this topic was brought up about a week ago, but I'd like to chime in, especially since Thomas already mentioned onw of my forges that did melt steel. The forge he was refering to was a two burer, naturally aspirated tunnel type forge that was lined with soft fire brick and it did indeed melt the end off my billet. I have since switched to a forced air, two burner box forge with kaowool sides and ceiling and a hard fire brick floor. It too has melted steel. This forge is much larger than what most hobbiest use (12x20x10" high on the inside) and is connected to a 100 gallon tank. The burners are the ones designed by Hans Peot in which several short sections of pipe of decreasing diameter are fit inside one another to create a flame holder. I have also melted steel in a friend's forced air forge. His is a single burer cylindrical forge, again with a Peot style burner. His blower is a hair dryer. One thing that I think is very important in achiving high temps from a gas forge, besids proper insulation, is sufficient mixing of the gas and air before it reaches the point of combustion. In my forge there are several 90 degree bends that the gas/air must make and this helps to ensure good mixing. The other very important thing is to have a supply of gas large enough for the forge. I have run my forge from a 20lb tank and it will heat steel, but it does not get to a typical welding heat because I can't get enough gas out of the tank fast enough, hence the 100 gallong tank outside the garage. It takes me about 5 minutes to get frost on the outside of a small tank with the big forge, whereas a small forge might go 30-60 minutes without freezing, and maybe longer depending the buring type and the psi being used. My big forge will burn about 1.5-2 gallons per hour when running full bore. I don't usually run it like that unless have a big block of steel that I am trying to heat, or several blocks stacked on top of each other. Forges burning natural gas can also reach the melting temperature of steel. At work we have furnaces capable of heating over 300,000 pounds of steel at once. If there is a malfuntion with the furnace, they can over shoot the temperture set point an if left unattended they will begin to melt the steel.
Most small furnaces that I have seen for blacksmiths will not melt steel, and that is not a big deal since you generally want to avoid this unless you are actually melting your own ingots. The point is that both propane and natural gas have the capability of generating temperatures high enough to melt steel if properly mixed with oxygen in a well designed furnace.

By the way, I had no trouble getting my local propane supplier to supply my garage with full tank pressure. I do have a regulater on the line running to the forge. I had orginally intended to run a second line from the large tank that serves my house, but the gas company said they couldn't have two lines with such different pressures coming from the same tank, so they brought me a dedicated tank.

Patrick Nowak - Sunday, 01/06/08 01:29:01 EST

Large propane tank...
I tried to get one but the local propane supplier wouldn't install/fill it unless they hooked it up to the forge. The fact that my gas forge is portable and I move it back and forth from the truck to the shop was a total show stopper.

I have a 40 pounder that I haul and a friend of mine has a couple of 100's in his shop but he hauls them in to get them filled.

Mike Ferrara - Sunday, 01/06/08 09:18:28 EST

Melting and Forge Temperatures: Some comments on Patrick's post.

I have seen a pile of billets melted together in a factory stock four burner NC-Tools forge. It was at a conference at high moderately high altitude in the summer. The forge was operating on a large bottle and had been running several hours. The door was wide open as the billets were long. There are also a number of metal casters that melt steel using simple propane burners.

As Patrick noted, A fairly large forge was in use AND it had a sufficiently sized fuel supply. In the case of the metal casters they were using a furnace sufficient to hold a 15 to 20 pound crucible and a large bulk propane tank.

When using a small bottle to supply a forge the evaporating fuel cools itself to cryogenic temperatures. When this is injected into the forge that very low temperature fuel reduces the maximum forge temperature. Even if the bottle does not freeze up and stop supplying fuel it is producing a "cool" fire. Large propane bottles have more mass at room temperature to supply evaporation energy to the fuel and it is delivered at higher temperatures. The warmer fuel is also less dense and mixes more readily with the air.

Mixing can be achieved by the length of the burner or obstructions in the fuel/air mix. Hand held propane torches use a grate or screen to break up the fuel/air into small turbulent flow paths which mix the fuel. One torch I have has a little gear set sideways in the base of the nozzle. It has a small center hole and the teeth make a series of holes as well. I thought it was pretty ingenious use of a stock part shape.

In the ABANA recupretive forge the burner tubes have pieces of sheet metal that are twisted (helical ribbons) fit in. These are low resistance mixers that could be added to many burners. Oxy-acetylene torches use the same system on a small scale at the connection end of the tips. Oxy-propane torches use many small orifices at the tip. These taper to force the fuel and air together.

In small forges everything is working against you. Heat loss due to the proportionately high surface area, low total BTU, operation on a small bottle, inefficient burners. . .

Small forges have a place. While an NC Whisper Baby is slow to heat up and will never get to welding temperature they are very handy for SMALL work and will run for a week or more of typical work days on a 20 or 30lb. propane bottle. They make less noise and heat the shop less.

I am sure it is possible to make a forge this size (about 3/4L) that can reach steel melting or welding temperatures. Using a couple smaller burners that mix the fuel better, using more efficient insulation and better door design. But as Patrick noted, the point of a forge is to reach forging temperatures NOT melting temperatures.

Right now there are a lot of cheap forges on the market that are poorly designed and manufactured. But you get what you pay for. Same with DIY forges. Most of the available plans are OK and work. But they are not for highly sophisticated efficient forges and many making them have a difficult time on simple aspects like proper drills for orifices. Personally I like temperature controls on a forge. This more than triples or quadruples the cost of a forge. But as noted, you get what you pay for.

Personally when I build forges it is to get a job done and I rarely fiddle with details. I've never had a gas forge fail. However, you have to use the proper parts and materials, have a few tools and know how to use them. Neophyte metal workers should stick to coal and charcoal forges.

- guru - Sunday, 01/06/08 10:07:03 EST

Swapping Motors: On any machine swapping motors and increasing HP is a significant change. Motor switches and relays (contactors) must also increase in size and tend to more than double in cost with each increase in HP. I recently put a contactor on machine with a 7.5HP 3PH motor. The cost for the wire, switch and contactor was about $600.

Air compressor motors are peculiar beasts that need high torque for starting. Even with a compression release the compressor flywheel and parts are a considerable load. Not all motors are up to the challenge. AND as VIc noted you must change pulley sizes to make a difference. This and the belt length change also mean changing hole locations. The pulley must match the type used on the compressor.

When you increase the capacity of an air compressor by speeding it up you also often need to increase the cooling of the air between stages. This means an intercooler coil (or a larger one) between the ports and in line with the flywheel/fan. Unless you are looking for this part it may not be apparent between two air compressors. . .

Last, but not least, safety release valves (pop-offs) are rated in CFM. When you increase the compressor capacity this part must also be upgraded to match the increase in flow. This simple innocuous part prevents the compressor tank from exploding from over pressurization if the control switch fails. It MUST have more capacity then the compressor.

On other machines increasing HP may put too much torque on shafts, couplings or gears and result in breaking parts. Machine designers calculate the stress on every part including for overloads, stall conditions and often crashes.

Never assume that making changes to machinery is simple unless you know as much about the machine as the designer did.

- guru - Sunday, 01/06/08 10:37:42 EST

I have two gas forges, a blown Hans Peot style that I built from the ABANA plans and a small single burner atmospheric. I built the blown first and have run it for perhaps 10 years. With a single 1" layer of Kaowool, it will melt steel, if run long and hard. I run it from a 100# bottle, and can throttle with the regulator. My blower is from an old optical comparator lamp cooler. The propane enters just down stream from an ELL, coaxial to the air flow. From the hundreds of hours of flow testing I did, including on these very forged ells, I can testify that the air flow is very turbulent about 1/2 to 3 diameters downstream. The flame holder works a treat. I have rebuilt the refractories several times. I now use an inch of kaowool, with ITC 100. I also use a half thick fire brick bottom, bedded in rammable. I diluted the rammable with some water and also slathered it up to about half the diameter of the forge for protection from snagging. I have a door similar to those used in industry, that is it is a metal frame with rammable facing and moves vertically and is counterbalenced. Works a treat.

ptree - Sunday, 01/06/08 11:01:03 EST

Ring Rollers, Building Machinery without a Lathe: You can build all kinds of machinery without a lathe but it really limits you. In the case of a ring roller the rolls need to be a certain size to withstand the stress. Without a lathe the bearings will need to be the same size. When using plain bearings you want small diameters to reduce the frictional torque. To use full size shafts you need to use ball or roller bearings. These increase size.

Good ring rolls also have at least two driven (if not all three) rolls and this means turning down steps for sprockets or gears and milling keyways. AND after hand cranking my tire bender for hours making rings I came to the conclusion that it would pay to have one of these motorized.

Personally, if I did not have the machine tools I would try to design as simple as possible and then get quotes on the pieces I could not make in house. In fact, even when you have the machinery, if you value your time it may be cheaper to have an expert make the parts.

Often the the most economical thing to do is to buy a commercial machine. There are a number of ring rollers on the market. AND, unless you need a LOT of rings all different sizes you can bend rings on bending jigs very efficiently. You just need a jig for each size and these do not require a lathe to make.

- guru - Sunday, 01/06/08 11:02:16 EST

Gas Forges- Since we seem to be on a gas kick, anyone out there using a ribbon burner? After meeting a glassblower at a party last weekend, I went back and re-read the article on them from the Hammer's Blow from a few years ago. They seem very neat, not least for their efficiency given propane prices. Anyone made one? Do you like it? Thanks!

Jud Yaggy - Sunday, 01/06/08 17:27:32 EST

Sarah; "The Royal Armoury at Greenwich 1515-1649, A History of it's Technology" by Alan Williams and Anthony de Reuck ISBN 0 948092 22 X mentions etching of armour as having been invented in Italy and that it reploaced engraving for the most part in the 16th century. Daniel Hopfer of Augsburg (c.1470-1536) is credited with perfecting the process on armour. It also mentions that embellishing was usually done at a seperate specialist workshop rather than at the armour forger's place.

Mann, J G, The Etched Decoration of Armour, Proc British Academy, 1942 28 17-45 plates 21 looked to be of interest in the 4 pages of bibliograpy the book had.

Thomas SKA Master wilelm the smith

Thomas P - Monday, 01/07/08 12:11:19 EST

Will boric acid work as a flux for forge welding? I asked a pharmacy if they had borax and they handed me a bottle of this stuff. Me not being a chemist or a student of chemistry didn't think much of it, but now I get home to find out that borax is actually a salt of boric acid. Will the stuff work or will I have to prepare an acid solution and mix in the sodium chloride, which if it works will release deadly chlorine gas I think and I'll have to evporate the borax out.

Nabiul Haque - Monday, 01/07/08 17:35:17 EST

Nabiul Haque, I buy "20 Mule Team Borax" in the laundry section of the grocery store. Comes in a several pound box, a lifetime supply. From your use of Pharmacy instead of "chemists" I am assuming, perhaps incorrectly that you are either in the US or Canada. If not you may have more issues to obtain the borax. If in the US go to the grocery.

ptree - Monday, 01/07/08 18:38:37 EST

Nabiul, I use a mix of straight laundry borax and boric acid I buy at the hardware stores as anti roach powder---98% boric acid. MUCH cheaper than buying boric acid at the pharmacy.

Hrisoulas' flux receipe uses a 2:1 ratio of borax to boric acid so that is what I have started using while waiting for the other components to arrive.

Thomas

Thomas P - Monday, 01/07/08 19:20:12 EST

Hmm I'll have to check more stores then for borax, I didn't seen any in the laundy section at shoppers drug mart. Then again they don't carry many things.

Is there a specific advantage to using mixed borax and boric acid?

Nabiul Haque - Monday, 01/07/08 19:29:01 EST

vise advice: Well I got my little 4" Iron City vise back in service. I was in worse shape than I thought not only were there nasty arc welds, but here and there it had been badly corroded and I had to lay down quite a bit of new metal. This one does have the little tabs back and front. If I had known how much trouble it was going to be I might not have bothered but it is satisfying to have it functional. I am now rehabilitating a heavy 5" vise. All it needs to be serviceable is a spring which I will make out of leaf spring.

Two questions. On all my leg vises the jaws dont close quite parallel and on two of them they dont close evenly - meaning the jaws are slightly to one side of each other. I am thinking of heating up the hinge with a rosebud and tweaking them - what is the easiest recommended way? Also the screw and box (Frank taught me its called the "box") on the 5" are in bad shape. I have some 1.5" Acme thread with nuts. I was wondering if I could cut the knob/ball (whats the right name, Frank?) off the existing screw and weld it onto some Acme thread? Is that metal likely to be weldable? Thanks

adam - Monday, 01/07/08 19:31:02 EST

Adam, Much of the large Acme all thread rod is "B-7" for strenght. B-7 is 4140, and will weld with the right pre/post weld heat treat. Without the pre/post heat, you will hear a snap noise as it breaks the first time you load it up:)

ptree - Monday, 01/07/08 20:20:03 EST

Adam,

I have four leg vises, all made of differing metals or grades of metal. One 5" is very minimally worked wrought iron, one 5" is highly refined worught, a 4" is probably double-refined wrought, and one 5-1/2" is part very highly refined wrought and part cast steel. The latter is, I believe a PW, based upont he appearance of the screwbox, though the legs are not chamfered. Interesting vise, though it may be actually an assemblage of parts from different vises. Dandy vise, though.

Based on the vast differences possible in the quality of the steel/iron you might run up against, I'd say about all you can do is try to weld it and see what happens. That will work for the screw, but how are you planning to do the screwbox? Just an acme nut isn't really gong to have much thread engagement, at least compared to a screwbox with a couple or three inches of thread.

You could always make a new screw and box the old-fashioned way with square bar and spiral it around a piece of round bar and braze in place, then do the same thing in the grooves of that thread but remove it and braze it into a screwbox. One of the groups had an article on just that process some years ago, though I'm sorry to say I can't remember which one it was. Perhaps someone else will know.

As for straightening out-of-alignment jaws, the first thing to do is to determine exactly where the misalignment is occurring. Then you heat and bend until corrected, being very careful to work at a high enough heat that you don't separate the wrought. Depending on the grade of the wrought, you'll need more or less heat to be safe. My vise with the very poor wrought is one that I wouldn't do at less than a full welding heat; fortunately, it didn't need that tweak.

vicopper - Monday, 01/07/08 20:30:42 EST

Nabiul,

Borax (sodium tetraborate) acts as a shield against oxidation and dissolves oxides. Boric acid is a reducing agent, preventing oxides from forming and reducing them back to an un-oxidized state. The borax, unless anhydrous, will boil and bubble as it heats up until it forms a liquid layer. The boric acid won't boil, just finally melt somewhat. They complement one another.

vicopper - Monday, 01/07/08 20:34:34 EST

Adam,

Yes, no, and maybe. I have aligned jaws by removing the movable leg, heating it in a big fire and straightening. If you can find a helper, you can run to the vise (which is clamped in another vise) align the holes, and have your helper quickly insert the beam-bolt. Close the jaw to see how you're doing. If not right, you still have some residual heat to take another heat. That may not be the best way. I suppose you could heat the pivot beam and tweak it, but it might take more heat than some rosebuds can provide, remembering that wrought iron is hot short.

I have a vise where the screw was replaced with an Acme. I don't know how they applied the male screw to the screw head, and the screw head looks original. If it was welded, the welder was one helluva welder. I find no evidence of a weld. For the female portion, the threaded tube was cut from the larger bell shape of the box, leaving the lug/stop in situ, and the Acme threaded tube was braze-welded on. It has worked for me for 30 years.

I have tried to weld on a new male thread to a screw head on two occasions, and in each instance, the weld broke after about one year's use. I used an arc welder, peened and wire brushed after each pass, and heat treated. It didn't work, though. Could've been the operator.

Frank Turley - Monday, 01/07/08 20:35:20 EST

Vicopper,

Your vise that looks like a Peter Wright...does it have slightly chamfered legs, a little deeper at the top and tapering to a point of zero at the bottom? I have a theory that some of the vises that stayed in the UK were like that. I saw a couple in Scotland. When I was in Australia, most all of the PWs were like that. The theory is that the early Peter Wrights were deeply chamfered on the legs, and they were sent to the U.S. The lightly chamfered ones either stayed in the U.K. or were sent to Australia, and they might have been made at a later date.

Frank Turley - Monday, 01/07/08 20:47:48 EST

Hi Guru,
I am expanding my workshop and have found a Nazel designed power hammer which I want to install.It is de-commissioned at the moment but in good working order.
I would like to find some information like manuals,specs,foundation requirements for this particular machine?
I have had no luck getting a response from the Nazel web-site. I am from Australia and have no contacts over here.
It has a plate on it that reads:

Lobdell Car Wheel Co
Patented 2119975
Size 12
Type S
Serial No 512

Does the Type S mean it can be set for single blows ? eg used for drop forging operations.
It does have an extra lever on it.

Any details or contacts would be greatly appreciated.
Kind Regards Tom

Tom - Monday, 01/07/08 21:04:30 EST

Ah very interesting. I guess I will need some of both then.

Nabiul Haque - Monday, 01/07/08 21:32:09 EST

Frank,

The legs have a notch in the corners just below the mount area, and the slightest hint of a tapering chamfer - no more than an eighth of an inch at the start fading to zero. Darn hefty legs, too. As is the post. The screwbox, as I said, has the classic PW grace and turning lines, deeply incised "FW" in the hidden area, and is clearly cast (or maybe drop-forged?) then turned. I can send you a pic if you're interested.

vicopper - Monday, 01/07/08 22:22:24 EST

Tom,

The guy to talk to for good information on Nazel hammers is Bob Bergman of Old World Anvils/Postville Blacksmith Shop in Wisconsin. Bob has rebuilt a number of Nazels and offered vast guidance to others doing the same. You can contact him through:

http://www.oldworldanvils.com/

vicopper - Monday, 01/07/08 22:30:57 EST

I am making a pattern for a swage block. The holes will be made out of various sizes of pipe, triangles out of angle etc. The shapes on the edge will be made similarly. I shall fill in the gaps with a decent cement mix. Then I have found a specialist caster who can use my model to produce a mould to cast the whole thing in sand. My two questions are how much taper should i allow in the holes? Does it have to be a taper? Could I just leave a shoulder? Also how much metal must there be between the holes? The cost of the actual metal is a very small part of the equation so I am happy to use as much as it takes. If it is a success I hope to go on and do some more complicated ones.

- philip in china - Monday, 01/07/08 23:34:04 EST

Foundry Patterns: Phillip, These are first made of wood or plastic unless you have the capacity to machine from the solid creating the draft as you go. In general practice metal patterns are made by first making a wood pattern, casting a metal part (often aluminium) then finishing it to the required finish. Since most metal patterns are "boarded" on a match plate (also often aluminium) machining flat and drilling and taping holes for the assembly is part of the process.

Draft varies depending on the process but for iron casting is generally 3/16" per foot and no less than 1/8" per foot is used. You want no more draft than necessary on swage blocks as too much can make the features useless. It is possible to make multi-piece molds that require no draft on the sides but this must be done in accordance to the specific foundry's methods and adds some cost to each casting.

Holes are NOT made in the pattern unless the pattern is thin and the holes of gross shape. Holes are made using cores (separate pieces of sand) that usually have no draft when of simple shape such as cylinders and rectangles. Cores are positioned by "core prints". These are extensions of the pattern.

See iForge demos number 98 and 99 on mold and pattern making.

I also recommend that you find one of the C.W. Ammen books on pattern making and any other available resources on casting.

A good way to start this process is with plaster molds and making plaster or plastic castings. These techniques are used in pattern making so there is no misdirection of education. Use a soap and watter slurry as a parting agent for plaster of Paris.

- guru - Tuesday, 01/08/08 10:48:11 EST

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