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 November 24 - 31, 2011 on the Guru's Den
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Stakes : He hasn't called by so maybe he isn't interested.
   philip in china - Friday, 11/25/11 04:59:36 EST

This is where I stake my claim...

Karen, if you are in the PA/NJ area there will be a blacksmithing event next month at Burholme Park Phila.
   - Nippulini - Friday, 11/25/11 10:36:14 EST

Philly Cheese-stakes! : I like cheese wiz on kielbasa that I cook over my forge fire. Sometimes I spill it onto my bick iron.................lol
   stewartthesmith - Friday, 11/25/11 11:48:44 EST

Best Steel for Fabricated Anvil : I have designed a london-pattern anvil that will be welded from five pieces of alloy steel. I would like to use 4340 steel because of it's higher hardness, but this steel is prone to crack during welding. The finished anvil will be fully heat-treated. Any thoughts?
   Marty B. - Friday, 11/25/11 12:46:28 EST

There's a restaurant near me called "Ray's the Steaks." Somehow it took *years* for to see the pun . . .
   Mike BR - Friday, 11/25/11 17:58:22 EST

Marty almost any steel worth making an anvil out of is going to have cracking issues, especially when using high thermal differential process like welding. Proper pre and post welding heat is necessary and perhaps annealing prior to hardening depending on the type of steel.

My heat treater's guide says 4340 is prone to quench cracking and that it should be put in the tempering furnace immediately upon quenching. Do you have a plan for heat treating?
   - guru - Friday, 11/25/11 18:27:59 EST

Fabricated Anvil : Yes, and it won't be easy. All of the pieces will require pre-heat & post-weld heating to 400-500 degrees, welding on a heated platen, and a full anneal prior to final heat-treatment & tempering.

FYI, I have re-designed the anvil slightly and it's now three pieces.
   Marty B. - Friday, 11/25/11 19:10:08 EST

4340 Anvil : Marty, only the face needs to be hardened. Maybe the body could be 1030 or something easy to weld. 4140 would probably do for the face plate and make heat treating a bit easier. Don't anneal prior to hardening, that just segregates the carbon into the carbides. Normalize instead at about 1600F or 1650F
   quenchcrack - Friday, 11/25/11 19:21:13 EST

4340 Anvil : I am tempted to ask the obvious question "why?" Is this just a project you want to do? It must be costing you a good deal more than you would be paying for a brand new anvil. I am curious.
   philip in china - Friday, 11/25/11 20:59:29 EST

Self Build - Forge Problems : Hey folks, I'm trying to get a self built forge up and running but I'm having real issues with it! I've had it going very well a number of times, so well I managed to melt the steel grate. I think the problem is airflow, or perhaps a lack of. I'll describe my setup but I'll also include links to photos below.

I first made a tray 6" deep, 3' by 2' and cut a 2" round hole in the base for air. I then welded a 2 inch T joint to the bottom, so ash could go down and air up. I then brought a bouncy castle blower and used an old 2 inch pipe to channel the air. I've been using a piece of old cardboard as an airflow control until I can setup a proper airflow gate.

I'm able to get a good fire going using either paper or bits of wood, and as soon as the fire gets going I am smoothing it with coke and increasing the airflow. It is then 50/50 on if the fire goes out or the coke catches. If it catches I can get right up to forging temps very quickly, but the fire soon starts to dwindle and no matter how much air I let through it goes out.

The blower blows enough air to blow the coke right out of the forge if I let it open all the way, so I don't think it is a lack of air supply, but I could be wrong. I keep reading about "fire bowls/pits" I don't have one of these, just a flat steel base.

I'll include the photos now. Guru, if you can see where I am going wrong, I would really appreciate your input!!

http://www.dumpt.com/img/viewer.php?file=7rls9z86uifdjlpmddo7.jpg
http://www.dumpt.com/img/viewer.php?file=pszcs70djp6cwshxpjc7.jpg
http://www.dumpt.com/img/viewer.php?file=hn0m7xc1nbikpen0z120.jpg
http://www.dumpt.com/img/viewer.php?file=jweag00ujgfi28wtrzwv.jpg

Thanks, Luke
   Luke Horobin - Saturday, 11/26/11 14:01:01 EST

Test : Test
   Test - Saturday, 11/26/11 14:02:28 EST

Coal forge : Jim,

You really need a proper firepot. Your fire is not going to be deep enough working on that plate, unless you build a *huge* fire. A typical coal firepot is about 8x11 inches with sides that slope to 3-4" deep at the grate/tuyere opening. The fire is usually built up until it is about 2-3" above the firepot in the middle. The firepot constrains the fire to a good size for most general work, and building it up that high allows the fire to maintain a sufficient mass of heat and also to have a "sweet spot" about in the middle where the atmosphere is roughly neutral.

On your plate forge you'd have to build the fire up to about 8" high to get the same conditions an you'd have a devil of a time keeping it form slumping down and out until the whole deck was ablaze. Since I'm pretty sure you're not building your fire that high, I'm guessing you can't maintain enough fire to keep the thing from burning itself out.
   Rich - Saturday, 11/26/11 16:10:25 EST

Coal Forge; Luke : The good news is that you can probably install either a commercial firepot, or fabricate your own, pretty simply. Aldren Watson's book; "The Blacksmith; Ironworker and Farrier" (ISBN 0-393-30683-6) has some relevant drawings and should be available through an Interlibrary Loan (ILL). The flatplate setup you have works on small "farm" forges or converted barbecue forges, but a decent firepot will give you much better capabilities.

Also, on your final picture, did the air grate melt? One of my early forges had that problem with a cast iron air grate (and many more problems beyond that); so I suspect that the heat is not going where it's needed. The other alternative is to mmake yours into a British style side-blast forge, which is handy if you work with charcoal a lot, but has it's own set of challenges and weakneses.

Overall, it looks nice (certainly nicer looking than my old wood-framed coal forge). Keep up the good work.
   Bruce Blackistone (Atli) - Saturday, 11/26/11 20:14:05 EST

Forge design update. : Early last month I dropped by to ask a few questions about my new forge design and get some advice on modifying it with an eye towards efficiency. Both Rich and the Guru were kind enough to offer some very good advice. I have incorporated several of the design changes they suggested. The forge is working much more efficiently and I think I can safely say the second stage prototype is a success. I am going to continue to run it for a while longer to see what other bugs crop up before I make the final version.

Gentlemen, Thank You both Very Much. Guru, reducing the size of the vent opening made a big difference in getting the ash build up solved. Also, raising the vent to the middle of the fire keeps it from getting blocked by the ash. Rich, I switched the little hairdryer from the low setting to the high setting after you pointed out the heat issue. The high setting doesn't quite get the steel up to a yellow but it is going into the brighter range of orange. I think in the next version I may use a clothes dryer blower if I can work out how to vary the speed when I want only to bend. Overall the setup is doing what I intended the forge to do but a little more versatility wouldn't hurt.

Thanks again,
Bill
   - Bill - Saturday, 11/26/11 22:31:41 EST

Bill's forge : Glad to hear things are going well on it, Bill!

As for the blower, if you really want to make an effective and efficient solid-fuel forge, the best bet is to get one of the blowers sold by Blacksmith's Depot. They are true pressure blowers, designed for forges, and work extremely well. The best way to throttle the air supply down is to make a moveable air gate that blocks off the INTAKE side of the blower. Air gates in the output side tend to make the blower work harder and just overheat the motor. Motor speed controllers don't save any electricity and don't have nearly the fine control that a decent air gate on the intake does.
   Rich - Sunday, 11/27/11 11:28:56 EST

Luke's Forge :
Luke, You have a bunch of issues. One, you are burning coke. Generally this makes VERY hot fire that needs a heavy duty fire pot and good air control. It either burns VERY hot, or not at all requiring a continous blast of air. Your grate has no mass around it to act as a heat sink and air is blowing under it. If you get a serious fire going in this forge you will not only melt the grate but weld the bottom out of the forge. You can see where it is burnt already.

Your blower looks like a very good choice for a forge but you MUST have an air control valve. A forge fire needs the most air to get started and then a fresh hot fire the least. With a fresh coke fire you can easily reach welding heat and with a little more air melt steel (including fire pots and forges).

Flat bottomed forges work OK for coal but do not focus the fire well. A fire pot limits the spread of the fire and creates a controllable hot spot. This needs to be located so that the steel is just above (not directly in) the hot spot. Your forge is too deep in general. If I were to put a fire pot in it I would have it set where your grate is and fill around it.

A common heavy duty grate is the triangular ball type (bellow)



This is a heavy block of iron that clears ash and clinker as well as controlling the fire. It is also simple so that it does not clog easily or burn out. I mush prefer NO grate, just a hole, than a grate that clogs or burns out. However, you get a lot of fuel in the ash damp and must clear it or the air blast will overheat the tuyere and burn it out. Your threaded ash dump will not suit. You need something you can flip open regularly without reaching down and touching the gate (which will be near read hot.) See our brake drum forge plans for two slightly different styles. One is below.



The sliding gate can act as an air control but is best used to just dump ash. The forge I used this system on had two handles, one for air control, one for the ash dump. The counter balanced ash dump is very common. You just flip it with you tongs, hammer or what have you. I've used them a lot as well.

Fire pots can be fabricated but the proportions are fairly important. About the size of one of the WWII English helmets is right. They can be made from plate as light as 1/4" but the heavier the better. You can also shape one from mud or clay. You fill a forge box such as the one you have built about half to three quarter full of high clay dirt and pack it to shape. Then mix a batch of clay to heavy molding consistency and line the fire pot. Sometimes a binder is used such as manure or a small percentage of Portland cement.

Look on the Blacksmiths Depot or Centaur Forge sites for what commercial firepots look like.
   - guru - Sunday, 11/27/11 17:55:56 EST

Anvil Prices : Ach! Mien Gott en Himmel! I went to the site of the company that now sells the 75 kg anvil I bought for $360 about 8 years ago. They now sell for over $1100!!!!! I need to sell mine and go find one of those danged Russian Anvils!
   quenchcrack - Sunday, 11/27/11 19:58:41 EST

Material and finish for andirons : I am fairly new to metalworking and live in Virginia. I am making a set of andirons. Is 1 inch square steel from my local metals distributor a good choice and what kind of finish should I use? Thanks and have a great day!
   Nick Racey - Sunday, 11/27/11 20:59:06 EST

Andirons : Nick, Due to the heat, a layer of tight scale (use a soft power wire brush) and then paint with DeRusto Barbecue black. If you want bright highlights use stainless (solid, components, or welded on highlights).

Size is a matter of scale related to the fireplace and size of fire. I've seen heavy railroad rail grates heated and loaded until they sagged to touching the hearth. . . A grate that weighed about 1,000 pounds (~450 kg).

For the front of the irons almost any size that suits the design is suitable. Of course this is scaled to the support leg. Common old andirons for a "standard" fireplace (one for a single room in a private dwelling) had 1" legs OR 3/4" if "economy sized". To prevent sagging a middle "leg" T welded to about 1/3 the distance from the front helps a lot. Since the masonry in fireplaces is often very uneven or out of square or level I make the middle leg about 1/8" short. If the irons are loaded to the sagging point the leg will stop the sag and custom fit the irons to the fireplace. The common grate for these is made of 1/2" square bar. Its a little light but that is what is sold. Custom grates should be heavier.



Andirons for public places where they have big fires for show need to be VERY heavy and have grates to match. Assume two men hoisting and dropping an oak log onto the red hot iron. . . I would use several mid legs and explain to the customer why they do not touch the floor when new AND that after they sag there will be a right and a left.

I like grates made from rectangular stock as you get more strength for the weight. After you quote the andirons ask the customer if they want a custom grate to go with them. . .
   - guru - Sunday, 11/27/11 21:39:26 EST

Ash Dumps : A note for beginners- always cut the blast before opening the ash dump! (As several folks have discovered at Camp Fenby over the years. ;-)
   Bruce Blackistone (Atli) - Monday, 11/28/11 11:17:11 EST

With the advent of self ballasted compact flourecent bulbs and the potential Obama based illegalization of incadescent lamps by 2014, does anyone suspect the price of tungsten and tungsten alloyed products to go down?
   - Nippulini - Monday, 11/28/11 12:28:28 EST

Just a thought...
   - Nippulini - Monday, 11/28/11 12:29:00 EST

get your facts straight : Nip don't blame Obama for a law passed in 2007 and signed by Bush
   - Ken - Monday, 11/28/11 13:35:51 EST

Same with bank bailouts. . .

I would not put money into the mercury filled fluorescent bulbs. . . The more durable, more dependable solid state LED's are going to replace them as well. However, they will not replace regular bulbs until the makers can figure out a way to limit their life the way they do incandescents (which CAN have a life in years).

Early this year (February) we had a discussion about the improved life of the compact fluorescents and we broke down a bought some. Out of a pack of 10, 2 were DOA. We installed 3 in the light over my desk. They have lasted longer than the incandescents had been but are starting to yellow and produce less light at 8 months of age. It is most noticeable when they are turned on. Very yellow for the first half hour until they warm up and then not quite as bright as when new. I am still not impressed.
   - guru - Monday, 11/28/11 14:26:04 EST

Brooks anvil : Since brooks nvils are cast steel. If I buy one with slight dishing or little chips on the edges I should be ble to get the face machined as long as I don't get to much removed right? I realize the temper only goes in so far but if I was getting less than 1/32 off I should have no problems. I also have a brand new rathole 250 if I need a perfect surface
   Cameron - Monday, 11/28/11 14:32:51 EST

Do you really need to pay for machining when a quick go over with a sanding pad on an angle grinder will do?
   Thomas P - Monday, 11/28/11 14:40:23 EST

Braiding steel : One of the smiths at Sutter's Mill forge is experimenting w braiding steel. Naturally, he started small (3 pieces of 1/4 round). Naturally, it didn't work.

OK, is there a trick to doing this? Always have the metal yellow or above? Pull tight as soon as you fold? Fold afterward w a good lubricant? Have five big guys?

You get the picture.
   Rudy - Monday, 11/28/11 15:00:00 EST

An anvil face is not a precision reference surface. Unless it has extreme wear I doubt a Brooks would have much if any sway. All steel anvils do not sway like the old wrought iron bodied anvils did. Edge chipping is almost always the result of undressed too sharp edges. Round those edges rather than sharpening them so they will chip more. . .

As Thomas indicated, a light sanding should do it. I prefer a hand held belt sander but most folks don't have one. However, I hand dressed my first two (very old) anvils with a common hand sanding pad and files.
   - guru - Monday, 11/28/11 15:02:11 EST

Anvil temper : Cameron,

I may be misremembering the numbers, but I thought hardening (followed by temper) only went in about 4 1,000s of an inch. Unless of course, it's one of those bizarre modern alloy deep hardening steels (which ain't likely).

Check first. Rehardening/tempering will be a terrible job.
   Rudy - Monday, 11/28/11 15:02:27 EST

Braiding Steel :
It can be done in the forge. But you do not get far with each heat unless you are very fast. Most braids are made using a torch OR a torch and a helper. I've braided steel and brass both using a torch. In all case the work is held in the vise.
   - guru - Monday, 11/28/11 15:05:44 EST

Depth of Hardness :
Rudy, you are confusing case hardening with regular hardening and tempering. Case hardening can go about 1/32" (.032" - 0.8mm) without damaging the surface. Open flame case hardening compounds only go a few thousandths tops. Hardenable steel hardens all the way through or very deep depending on the size of the material and the method of quenching.
   - guru - Monday, 11/28/11 15:10:30 EST

Braiding steel : In addition to the torch/vise method, there is the 4 rod E-Z braid. Take 2 rods, twist clockwise. Do it again with two more rods. Put both rod twists in the forge, bring to the vise together and twist both bundles counterclockwise. The rods will intertwine naturally.
   - Nippulini - Monday, 11/28/11 15:27:18 EST

Shallow hardening. : From my reading, I believe that W1 is considered a shallow hardening steel, especially compared with O1. This is what I remember. If the W1 piece is 5/8" thick or less, it will harden all the way through. If the piece is larger than 5/8", you'll get a partial exterior hardening and the interior will be a "tough core." This used to be called the "case-core effect" having NOTHING TO DO with case hardening. I can't give you a ratio as to how deep the hard case might be compared to the core, but it would be much deeper that case hardening on mild steel. The case-core effect is related to the rate of heat abstraction. It is not all bad. For example, on a 1 1/2" hammer face of W1, it won't harden throughout; it will get the tough core. When tempered, you'll have a nice tempered case, and the core acts as a "cushion" for the tool.
   Frank Turley - Monday, 11/28/11 19:15:36 EST

Nip,

The tungsten "commodity summary" here: http://minerals.usgs.gov/minerals/pubs/mcs/ says that 50% of tungsten production in the U.S. is for cemented carbide tools. Filaments is one item in a pretty long list that accounts for the other half. So I'm guessing that phasing out incandescent lamps won't have much price impact.
   Mike BR - Monday, 11/28/11 19:16:45 EST

Thanks for the help on andirons! : Thanks for the information on the andirons - I have my metal and took your advise on the rectangular horizontal piece. Really apreciate the fast turn around on the response - THANKS for being there. Have a great Christmas and God's speed to all the Gurus. Nick
   Nick Racey - Monday, 11/28/11 20:33:17 EST

Titanium : I watched a program this afternoon on how titanium is made. It takes about six weeks to make a batch of it. They use water to seperate the titanium ore, kind of like panning for gold. Then they have to remove other compounds, metals, etc. Then they have to convert the ore into a gas, also adding other gasses. Then converting the gas into a solid. One of the advantages of titanium is the fact that it resists extreme heat, that is why it is used in jet engines ( turbine blades ) etc. They said when a SR1 Blackbird is flying along and a missle is shot at it, all it has to do is accelerate and out run the missle. At these speeds, if it was made out of any other metal, it would melt in mid air !
   Mike T. - Monday, 11/28/11 22:10:07 EST

Case Hardening : Mr. Turley brought up a subject that I have thought about before. I remember owning a 1903A Springfield rifle, and a man told me the metal had been case hardened. He drilled one for a scope and had to use a punch to punch through the surface before drilling. How was this process done ? I believe carbon is forged into the outer surface, but how is that done ?
   Mike T. - Monday, 11/28/11 22:23:47 EST

Mike, "Forging the carbon in" is a myth.

Most commercial case hardening is done by a process called "carbon nitrating". Either a carbon rich solution like a melted cyanide salt bath, or an a special atmosphere is used at high temperature. But on small pieces the method of sealing in a carbon filled (bone charcoal) container and heating to where the iron becomes chemically active and absorbs the carbon is still used.

Early gunsmiths used the charcoal method with parts sealed in a clay pot or crucible to prevent oxidation. All kinds of small parts were case hardened this way. Triggers, screws, frizzens to create a hrad wear resistant surface OR in the case of frizzens a hard sparking steel.. . . Modern weapons use modern methods.

Low and some medium carbon steels are case hardened. Those with sufficient carbon will harden internally and be VERY hard on the surface. Heat treating tempers the core.
   - guru - Monday, 11/28/11 23:33:57 EST

secrets of color case hardening : This old gunsmith told me that you could get mottled colors on the case hardened gun parts by using an aerated water quench. You'd have air bubbles running throughout the water. He said that leather gave red and bone gave blue. ¿Quien sabe? I'm just passing this along.

The guru mentioned charcoal for packing around the gun parts, but other organic, carbonaceous material could be used like ground, charred bone, leather, hoofs, and horns. Those ol' boys would heat the casing pot to a red heat and hold it at heat for five to six hours, then dump the contents into water.

Nowadays, we have carburizing compounds, like Kasenit, that work much faster.
   Frank Turley - Tuesday, 11/29/11 00:11:03 EST

Searching for the secret of Color Case Hardening is what got me into blacksmithing. When I was a kid I was intrigued by the marbled effect on shot gun receivers. I had this idea about making jewelery with that finish. I figured if it had to do with steel a blacksmith should know. I read everything about coloring metal in Machinery's Handbook. . not go, I started looking for books in the public library. . . This was in the 60's before the resurgence in interest in blacksmithing. The only books on the subject in our local library were the Eric Sloane Americana series which did not get into such details. My standard for the quality of an encyclopedia became whether or not they had an article on anvils no matter how brief (you would be amazed at how many have no reference to this historically indispensable tool).

I looked for the secret of Color Case Hardening for decades. . . Then while studying gunsmithing when I thought I wanted to build a black powder rifle, there it was. . . You never know where your interests will lead you.

The REAL secret of color case hardening is amount of air, distribution and depth of the bath.
   - guru - Tuesday, 11/29/11 01:49:41 EST

Color Case Hardening : One of the Machinist Bedside Readers by Guy Lautard has a detailed description of the process for amateurs; aerated water, bone and leather, etc.,.
   - Tom H - Tuesday, 11/29/11 07:31:02 EST

So Jock, I am assuming you gave up on the jewelry? Would this color case hardening show on stainless? I'm sure it wouldn't last very long though...... I'll give it a go.... time to hook up an aquarium air pump in the quench bucket!

OH!! Speaking of quench buckets, I found an old mini barrel. It was dried and the staves were loosed. After filling and filling with water the staves swelled pretty much shut but it stil has a few leaks. Any ideas on how to seal it so I can use it in the shop? I was thinking of coating the interior with tar, but can't find any.
   - Nippulini - Tuesday, 11/29/11 08:44:34 EST

On the way to looking for color case hardening I became more interested in the forging, welding and machining aspects of metalworking. But I have made some brass and stainless jewelery as well as some repousse' pieces. Color case hardening will not work very well on stainless.

The case hardening part has nothing to do with the color. Its the heating in an air-free environment and then the quench.

The metal that makes the most brilliant temper colors is Titanium. I have a piece of Titanium Star Trek jewelery that was given to me as a gift many years ago. This would be the stuff to play with fancy temper colors.

Leaking barrel: Did you try tightening the hoops (driving them on farther)? Any interior water proofing will result in a dry barrel that falls apart. Often the leaks will close with time (a week or two).

When barrel staves get loose dirt or grit occasionally gets between them and result in leaks when you refill. . Oak being hardwood is not very compressible so the debris holds the staves apart. However, as I noted above, with time the pressure of the expanding wood may seal the leaks.
   - guru - Tuesday, 11/29/11 09:52:48 EST

I'll try tightening the hoops, it's been soaking for about a month now. I placed it next to my rain barrel right under the overflow drain, so when we get rain (man, we get rain!) the overflow fills the smaller barrel.
   - Nippulini - Tuesday, 11/29/11 10:08:53 EST

After a month it may just be a leaky barrel. . . You could let it dry out, clean it, tighten the hoops a LITTLE and try again.
   - guru - Tuesday, 11/29/11 10:27:49 EST

Incandescent Light Bulbs : If you can still find them in your area, buy larger wattage than you need. Put them on a rheostat switch and turn it down a bit when turning on the light. The light/lights will last forever.
One way to get past the built in obsolescence
   Carver Jake - Tuesday, 11/29/11 13:05:05 EST

anvil : im looking to buy a farrier anvil for my collection Im attracted to a centaur that says burlington wisc and made in sweden its 135 lb and has a clip horn on the side My question is do you think there might be a market for it 20yrs from now especially since you can buy new ones for a song
   vern kelderman - Tuesday, 11/29/11 15:02:07 EST

Vern : Must be some new secret song.
They don't play that one around here, that's for sure.
   - Tom H - Tuesday, 11/29/11 17:24:44 EST

Vern, : Centaur clip horn anvils are OK, but I don't see one as an investment.
The original developer of the farriers' pattern was S.D. Kimbark in 1882. If you could find an anvil that was stamped on the side S.D. Kimbark Chicago, you might have something. For a few years, Kimbark was having the anvils made in Germany, and then Hay-Budden of Brooklyn, NY, took the contract. There are quite a few Hay-Budden farriers' anvils which can still be found in the used anvil market. I've got two H-B farriers' anvils, and they are probably worth a little more than the Centaurs. Depends on who's buying.
reference "Anvils in America" by Richard Postman
   Frank Turley - Tuesday, 11/29/11 19:26:37 EST

sparks : Last night was the first time I used my charcoal forge when it was really dark. I have a super sucker side draft hood, with 16 feet of pipe above that. I have plenty of draft. I had more fireflies in the forge then normal. I went outside and noticed a spark coming out of the chimney intermittently. I was wonder how concerned I should be about an accidental fire.
Milton
   Milton R. - Wednesday, 11/30/11 06:57:05 EST

As concerned as you should be if someone flicked a lit cigarette in the same area... maybe even less. Although if you are storing your flammables there......
   - Nippulini - Wednesday, 11/30/11 08:37:12 EST

Heat Treat Foil : Hi folks. I'm looking for some advice on heat treating some 4140 hammer heads. I want to protect the surface from oxidation but I don't have a local supplier of ss foil. I do happen to have some light guage copper foil though. With the melting point of copper being in the 1990s and the hardening temp of my steel being in the 1500s I think the foil would hold up. My concern would be with the two metals reacting with one another. What are your thoughts?
My other option is to get the electric oven hot before placing the steel inside to try and reduce the oxidation but I'm worried that I'll damage the steel without a preheat. Thoughts? Thanks a lot!
   Brandon - Wednesday, 11/30/11 10:27:07 EST

reply : Frank: thanks for the information this anvil is still painted green and was made by Kohlswa If i was told it was never used i couldnt disagree ive been able to date it around 1985 ive noticed that anvils by this company go awful high on ebay
   vern kelderman - Wednesday, 11/30/11 11:01:18 EST

Fire due to sparks :
In some localities you are supposed to have fire suppression screens on your fireplace chimney. This may apply to burning charcoal in a forge as well but building codes generally do not know . While the screen will not stop the fire fleas it will often break them up. Any floating paper used to start the fire or induce a draft will be stopped or broken up. This is often the big concern.

Some judgment and common sense is required. If you live in a high fire area or have a wood shingled roof you may want to be concerned. If you live in a lush green or average rainfall area the concern would be less. Tin roofs are the best bet against flying sparks. In our area I would normally not be concerned but this year we had record weed and grass growth that has not yet been cut. . . the dry grasses are a fire hazard.

In Costa Rica where it is quite hot and moist but sometimes dry and windy they use charcoal forges in wooden building with no chimney, just letting the smoke go out the gaps at the edges of the roof line. Doesn't seem to be a problem.
   - guru - Wednesday, 11/30/11 11:56:09 EST

water twist : would really love to know how to do a water twist
   katie - Wednesday, 11/30/11 11:57:45 EST

Heat Treat Foil :
Brandon, I would save the copper for other purposes.

Other ways to protect the steel Re to seal it in clay, or to heat it in a sealed container (crucible's work) filled with charcoal. You would get a slight case hardening but not much just heating to the hardening temperature and holding it fro a short time.

In the end doing the final finishing last is often the most efficient way to go.
   - guru - Wednesday, 11/30/11 12:00:11 EST

Water Twist :
Never heard of that. Can you describe it?
   - guru - Wednesday, 11/30/11 12:01:12 EST

Average rainfall can be a big factor. Here in New Mexico we have had less than four inches of precipitation since January 1 2011. We also get high winds and piles of things like tumbleweeds that burn like they were soaked in gasoline. Here sparks are a concern.

Where you are at I don't have a clue.

My concern would be "what if?" If a stray spark had little chance of hitting anything combustible I might worry. OTOH I forged in an 80 year old wooden garage with leaves in the odd corner for 15 years without any issues, just sloshing some slack tub water back behind things if I had a worry. (funny that garage mysteriously burned down a couple of months after I moved---no electrical service so how did it start?)
   Thomas P - Wednesday, 11/30/11 12:08:40 EST

Water Twist : Isn't that what the water does in the toilet bowl?

Sorry.....
   quenchcrack - Wednesday, 11/30/11 12:50:48 EST

Hello I have a traction question about roll benders. I built one last year. It has enough torque but the rollers slip. The two bottom drive rollers are 2.4" diameter. Will I have more traction with one 10" diameter drive roller on top and two idlers on the bottom? I would adjust the gear ratio. I have photos I can send but I don't know how to post them on this forum.
Thank you for any constuctive criticism you may have.
   - Dan - Wednesday, 11/30/11 14:19:01 EST

Water twist? : Can't remember who the demonstrator was, I think he normally worked at a public venue. He had this great routine where he would heat a bar, plunge it in the slack tub, twirl it around a bit and bring it out with a perfect twist! Really wowed the crowd. "I always wondered how they did that". Well of course he had twisted a bar ahead of time and placed it in the slack tub and just had to make a switch. Sounds like someone has picked up the trick again.
   - GRANT - Wednesday, 11/30/11 15:43:23 EST

Roll benders- Torque is one thing, and you cant have too much of it- but the other thing that is needed is pinch- downforce on the central roller. Most commercial benders have an acme screw that is a minimum of 1 1/2" in diameter to hold the central roller down, and it slides in grooves milled in a 100lb or so block of steel to hold it rigid.
Higher end machines use hydraulic cylinders to hold the central roll down, and pinch the metal. Obviously, this increases the need for torque.
Rule of thumb is, 2" square material needs at least 3hp, and then the force needed goes up with the square of the increase in size- a machine that will do 4" angle needs to be about 15hp.
One workaround on lighter duty machines is serrated rolls. Almost all cheapo (under ten grand) angle rolls use serrated rolls for flats, square, and angle, so they can slide by without full hydraulic pinch and without really enough horsepower.
But serrated rolls scratch up your material.
There is no free lunch- decent roll benders need to be very heavy, very massive, machined to be very rigid, have lots of torque, and lots of HP.
Also, 2.4" diameter rolls are probably too small to grip enough material- in a machine that bends in the 1 1/2" square tubing range, lower rolls are usually 6" to 8" in diameter, and, of course, they get bigger as the capacity increases.
   - Ries - Wednesday, 11/30/11 17:02:13 EST

4140 scale; decarb? : I've done a lot of hammer heads with water hardening steel, and I've not worried about scale or surface decarburiaztion. Gonna' polish up the faces anyway. I read that 4140 hardens at 1525-1575ºF, a scaling heat. I'm not a metallurgist, but I don't see the problem, unless I'm missing something.
   Frank Turley - Wednesday, 11/30/11 18:11:18 EST

Rolls :
1) Old rolls used cast iron tires on steel shafts. I think the porous texture of the CI gives better traction.

2) Diameter is only needed to give the roll strength for the given span. The wider the rolls the larger the diameter needed for a given thickness work. Remember that deflection increases by the CUBE of the increase in width. .

3) Having top and bottom rolls driven increases the driving power by almost double. But this requires gears and a great deal more expense.

Champion Tire Bender
Champion Tire Bender

The tire bender above has 2.5" or 3" diameter rollers. Two are driven and one is adjustable. These rolls will easily roll 5.5" x 1/2" (or 5/8") flat into wagon tires. I've easily rolled an 18" diameter from 3/4" square in the same. It took several passes thus LOTS of cranking.

We rolled 1" pipe and 1" x 5/8 Channel into 80" circles using one like it. The legs of the channel made a crack in the top roller and broke the cast iron. We made an all steel replacement that worked OK. Rust helps with the friction. . . We also made a form fit adjustable roll for the pipe to reduce flatting and make it easier to get it into the rolls.

The good feature about these rolls is the middle roll pulls out and the two driven rolls are fixed centers so the gearing works well. The bad feature is the dual adjustment screws. I'd like to put a chain and sprockets between them with a common central drive. But that is a lot of work for a machine that only gets used every couple of years.

The first use of rolls I ever saw was at a craft's show where an old fellow had the gear box out of a rotating sign and was using the one driven roll to make 3" to 8" diameter rings from 1/2" square material. The shaft was only about 1.5" in diameter.
   - guru - Wednesday, 11/30/11 19:07:49 EST

Mr. Turley,
I'm worried about the scale messing up the quench. I'm also thinking ahead to using the same material for power hammer dies. I'm doing this for practice because it seems the hammer dies need more tlc in the hardening process. So, do you think the scale has any negative consequences in the heat treatment? I'm not really concerned about looks. Thanks
   - Brandon - Wednesday, 11/30/11 19:27:15 EST

Scale, decarb : Mr. Turley,
I'm worried about the scale messing up the quench. I'm also thinking ahead to using the same material for power hammer dies. I'm doing this for practice because it seems the hammer dies need more tlc in the hardening process. So, do you think the scale has any negative consequences in the heat treatment? I'm not really concerned about looks. Thanks
   - Brandon - Wednesday, 11/30/11 19:28:45 EST

Scale on the Hammerhead : Brandon, you will decarburize the hammer head only a few thousandths of an inch in the heat treatment. You probably did a LOT more decarb'ing in the forging process. As Frank points out, you will grind the face anyway and that should remove the decarb. The scale will flake off almost instantly in the quench and pose no problems. Just do it.
   quenchcrack - Wednesday, 11/30/11 20:22:10 EST

Waggon tyre roller : Hi Guru, Does that tyre roller you show have a provision to make the rollings slightly conical ? Or is it more so a 'roughing-in' tool and the final shape of tyre was adjusted by hand?
Or Maybe its not the customary USA design to make waggon wheels dished and the axel stubs slightly canted downward ?
Just curious...
Sven
   - Sven - Wednesday, 11/30/11 21:05:37 EST

Wheel cant and conicalism : Sven, Dishing a wheel is standard. But the tire is not conical that I know of. Or perhaps some are. I've noticed the type of wheels you refer to in European movies but I think American wheels are different. The bender above has two adjustment screws on the adjustable roller. Adjusting these unequally will result in a conical ring. For more details we would have to ask a wheel wright.
   - guru - Wednesday, 11/30/11 21:52:13 EST

Scale and Heat Treat :
Brandon, if you are making power hammer dies, those are big expensive pieces of steel. The stainless foil would be a small investment. Rolls of foil can be pricey but envelopes can be had individually. McMaster-Carr has envelopes large enough for 48 to $12 each. They also have small rolls for reasonable prices.
   - guru - Wednesday, 11/30/11 21:59:51 EST

Wheel cant and conicalism : I remember hearing my grandfather going on about a conical tyre, I thought was un-needed & extra fussy considering it would be at best but a couple degrees of taper on most wheels unless the tyre needed to be extra wide or unusually small diameter for some reason.
Sorry to the guys who think this topic is wierd & obscure, But you might be suprised over the amount of detail that must be designed into something apparently simple as a waggon.
   - Sven - Wednesday, 11/30/11 22:11:05 EST

Brandon,

Even if you *did* need heat treating foil, I doubt the copper would work. Copper melts a few hundred degrees above the temperature you need, but below typical forge temperatures. Thin foil would heat up *very* fast, especially where it wasn't in direct contact with the steel part, and I suspect you'd have trouble keeping it from melting. And copper's high thermal expansion rate means that no matter how neatly you wrapped it to start with, you couldn't keep it in uniform contact with the steel.

Also, even at 1600 degrees, copper is *very* soft. I doubt the foil would hold up to any type of handling. Conceivably air current in the forge might even be enough to tear it.

But you could always try it on a scrap piece and prove me wrong . . .
   Mike BR - Wednesday, 11/30/11 22:21:29 EST

Iron tires : I think in the U.S. the rires were not canted. I have a copy of "The Wheelwright's Shop" by George Sturt, but presently my retrieval system is off. This book is a delightful social history, but Sturt puts in some contsruction details. He thought he was the last wheelwright in England to work on the construction of farm wagons (early 1900's). I think the book is still in print.
   Frank Turley - Wednesday, 11/30/11 22:52:10 EST

Iron tires : Canting the tyres would require tapering the soles of the felloes also, Again alot of extra work.
Maybe it did differ based on the waggons expected work environment.
For a waggon run mostly on paved streets might work out to justify the extra fussiness, where a waggon over mostly dirt roads would not be worth it. Who knows... Just curious, Interesting to think of anyway.
   - Sven - Wednesday, 11/30/11 23:19:35 EST

Sven, I've seen heavy conicalism in films. The bottom of the wheel is vertical (perpendicular to the ground) and the upper part slopes out as much as 10 degrees. You don't see it unless you are in front or behind the cart/carriage. I think other types had a dish to the wheels but no conicalism to the running surface. Both methods work and I think mostly a matter of style.

   - guru - Wednesday, 11/30/11 23:42:05 EST

leaky barrel : nipulinni,try throwing a good handful or two of fine sawdust into the barrel and leave it sit. Same principal as rad leak stop I think.
   wayne @nb - Thursday, 12/01/11 08:00:13 EST

tyres : hard to explain without pictures, but as far as I know tyres were not conical. Even the heavier wheels that had strakes on them rather than tyres were just square. A wheel is dished to give it strenght. (It amazes me how a few pounds of iron and woos can carry well over ten times it's own weight) to counter the dish of the wheel, the end of the axle is dropped a bit so that the spokes are almost at a right angle to the road. The almost right angle, instead of a right angle was so that if one side was higher than the other that the spoke would then be at a right angle, and full strength.
Doing cones in a roller is fairly simple, just curve the flat bar the hard way by the right amount before running it through.
   JimG - Thursday, 12/01/11 09:06:44 EST

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