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This is an archive of posts from June 1 - 7, 2011 on the Guru's Den
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Sharp Edges : Once more an illustration of perception vs. reality. In the machine (machined?) age sharp corners and edges are either "new" or "gently used" and therefore superior. Rounding implies wear and tear and age. (Hmm, that sounds like most of us blacksmiths... ;-) Nice straight lines and sharp corners are just fine on a lathe bed; anvils are rather the exception to the rule following the Industrial Revolution.

We worship the straight, the flat, the clean, the regular, the symmetrical. Even our curves must be clean and regular. I think this is why blacksmiths are fascinated with the sinuous, the organic, the dendritic; leaves and branches and snakes and other irregular shapes. "Because we can." Sort of like Thomas's story of the machinists and the corkscrew- our minds tend to run in a different track.

Hot and sunny on the banks of the lower Potomac, and I’m off to the cardiologist today.

Visit your National Parks: www.nps.gov

Go viking: www.longshipco.org
   Bruce Blackistone (Atli) - Wednesday, 06/01/11 09:09:30 EDT

The Machine Mentality : I second what Bruce said. Peter Ross gave the keynote talk at the Asheville, NC, conference, and he talked about what he called the machine mentality. I jokingly say that everyone wants the work to look like an electric toaster. Peter was in a shop where his smith friend had a fire going and needed to cut a piece. He walked 60' to the other end of the shop and used the chop saw. He could have heated the piece and used the hardie or hot cut, but no! The chop saw gave a neater, polished, 90º cut. I say, "Get over it!"

I make many of my strap hinges out of 3/16" stock with a 7/16" or 1/2" ID welded barrel. I've had more than one customer ask whether it would really be "strong enough." Yet they will purchase a standard five knuckled hinge of sheet metal with a small pin. They do not ask the hardware salesman if it is strong enough.
   Frank Turley - Wednesday, 06/01/11 11:18:28 EDT

The Machine Mentality : Frank I have to agree. I have a former co-op student who after getting his masters in Mechanical engineering, took over his Dad's sheet metal shop. He had grown up in that shop, and is a master sheet metal guy and has been since he was 20. He can CAD with the best, do finete element anaylisis, and yet his shop is "Tape measure" accurate in his words. He always quotes that way as well. And he makes a good living as his Dad did, and works about 45 hours a week and has a familiy. No CNC, no CMM's just a tape measure, and protractor and a huge knowledge of what he is about.
I have spent my career working in precision machine shops and am very used to drafting to the ten thousandth, measuring to that and machining myself to the thousandth. I have even measured in Millionth's and lapped to that level, but when I am in my shop at home, I usually work to Tape Measure accuracy. And I unstress making things that are pleasing to the eye and made to the accuracy of the simple tape measure and by eye.
Disclaimer, I do make machined parts when I am building machines at home and work to the necesary accuracy, and while it is very sastifying when everything fits and works as I intended, I find banging out a trowel by eye, and using a straight edge as the only measuring tool to be more sastifying yet:)
   ptree - Wednesday, 06/01/11 19:51:19 EDT

Acme Threaded Nut : Do you know where I can get an acme threaded nut for a leg vise? Although the screw is intact, my nut is stripped, and I need a replacement to restore this vise. Thanks!
   Stewartthesmith - Wednesday, 06/01/11 20:34:14 EDT

coal/coke supply near las vegas : doeseny body know a coal or coke suppler near las vegas NV
   iwasherefirstman - Wednesday, 06/01/11 20:41:11 EDT

Stewart - Acme Nut : Are You sure the vise screw is an Acme ? Unless it has been replaced with an Acme thread, it probably isnt.
   - Dave Boyer - Wednesday, 06/01/11 20:42:36 EDT

Vise Nuts and Threads : Stewart, The old vise threads met no standard other than the vise makers and were often hand made making the situation even worse. That means the pitch in threads per unit (most commonly given as threads per inch in English units) may or may not have met a specific standard. Even in standard threads these are not always whole numbers. Coarse threads come in 2, 2¼, 2½, 2¾, 3½, 4, 4½, 5. . .

Old vise threads tended to be square threads, not slope sided Acme.

The early threads were made by coiling square bar around a hand turned screw and then brazing the coil into a hand fitted tube. Needless to say, some fit much better than others.

Later threads were machined in the nut (the solid box). Exact techniques not know but I would expect a lot of hand fitting on old vise. But vise threads remained largely square threads until fairly recently and some still are. The difference being the newer threads are most likely some standard.

Another rare high load thread is the buttress thread. This has a 90&176; load face and a sloped back. Square threads under high loads often deform into looking like buttress threads.

So, besides the question of pitch you have the thread form which may or may not be a standard. Leg vises, being sold in 5 pound increments were made proportional in nearly every respect. Some parts probably spanned sizes but I do not have exact dimensions. I suspect that many were in 1/16" increments, possibly less. With threads ranging from 1" to 1-1/2" that is a minimum of 9 sizes, possibly more in any one manufacturer's line.

McMaster-Carr sells various Acme nuts but the range is limited compared to the variations of vise threads. I've bought Acme all thread and nuts, including long coupling nuts from McMaster-Carr. They are not cheap but they are less expensive than having them made.

Step one, measure. Step two measure. Step three measure. . .
   - guru - Wednesday, 06/01/11 22:05:00 EDT

Worn out Vise Threads : Years ago I bought numerous old leg vises that were missing parts. I even picked up a few loose parts such as bench brackets in antique shops.

I had one vise that was abused and mangled but had a screw and box, and another that had a good frame and a matching size bench bracket. I put the screw from one vise into the other and everything seemed perfect. The screw worked and tightened nicely. But then when I was demonstrating it to someone I tried to clamp a 1/2" bar. . . When the jaws closed the screw held, but at 1/2" the threads slipped! At 3/4" it held weakly then slipped. . .

This made sense. Threads are going to wear at the point they are used. The nut wears in its entirety but more toward the front where debris gets in the threads. But the screw wears in the range it is used in the most. Clamp thousands of pieces the same thickness for decades and the screw wears out in that zone.
   - guru - Wednesday, 06/01/11 22:23:58 EDT

If you are going to replace the "nut"; replace the screw at the same time!

I'll pick up a vise in pieces as long as the screw/screwbox is in decent shape. If it's messed up then I'll only get it at scrap rate...

Thomas
   Thomas P - Thursday, 06/02/11 13:57:25 EDT

Old Vises and Repairs : Back when I was buying junk vises I was paying $5-$10 each. Good vises were selling for $25! The problem with junk and partially complete vises is most have the same missing or worn out parts. Nuts and screws are the most commonly worn out parts and bench brackets the most commonly missing, along with springs. Screws have often been replaced with poorly fitting (or ugly) replacements. Sellers always wanted too much for these and I passed on them.

Springs are the easiest part to replace. Bench brackets can be replaced with a U-bolt and angle iron but its not pretty. Screws are the most difficult and expensive part but a first class bench bracket is just as difficult.

If the old screw and box are still with the vise I would repair them with a replacement screw and nut welded to the original parts. Welding a new screw to the old handle is not a difficult task. However, I would machine a stub on the screw and bore a hole in the handle shaft so the parts align perfectly and the joint is strong.

Repairing the box is a little more difficult. Depending on the type and age it can either be cut off and a new long nut welded on OR bored out and a threaded sleeve installed and welded on. In either case some machining might be involved.

Note that a length of Acme all thread and a coupling nut will cost about half as much as a good used vise. Add some labor and the vice had better not have cost very much to start. On the other hand, these are wonderful old tools that are selling for less than their actual value as tools and the nice ones deserve restoration. But poor quality work will result in a tool worth less than before the repairs. . .

To avoid a lot of this trouble be sure to clean and lubricate that vise screw once in a while!
   - guru - Thursday, 06/02/11 16:21:37 EDT

I have really liked a retrofit I have seen of putting a zerk on the end of the screw box and pushing some grease through that on a regular basis.

The other big helper for vises is a set of spacers to use on the opposite side of the jaws when you want to crank down on it.

Thomas
   Thomas P - Thursday, 06/02/11 18:04:36 EDT

Vise Differences :
Late vises came with spherical thrust washer sets but I think early vises had none. Or at least many are missing. I found that stacking several large flat washers under the head of the screw lubricated with never seize made a very smooth thrust bearing and keeps the screw and jaw from wearing.

Frank Turley has noted that the little duck tail on the front of vises is a device to keep grit from getting into the bearing surface of the screw. This continued on many bench vises and has only disappeared in the past 50 years. Many of the vises that do not have this feature have a recessed thrust surface to do the same thing. A few have a "fender" effect to keep the dirt out.
   - guru - Thursday, 06/02/11 19:31:44 EDT

Leg Vise Proportions :
Pair of blacksmith leg vises from Parlett Museum sale.
Pair of English Blacksmith Leg Vices from the Parlett Farm Museum sale.

The photos of these two vises were sent to us by StewartTheSmith. The smaller vise is one of two he has for sale.

I arranged this image to show the proportions of large and small leg vises. The larger the vise the larger all the parts except the length of the leg. Since all these vises are the same approximate height The smaller vise is far from the smallest. To have 30 pound vise next to a 250 would be very dramatic.

The point being that these tools were scaled up in almost every respect. Each 5 pound increment has wider jaws, larger screws, longer handles AND close square on different size work. On the vises above the smaller vise closes square on about 5/8" stock and the larger on stock over 1".
   - guru - Thursday, 06/02/11 20:20:07 EDT

help!!!!!!!!!!!! : does anyone in here have a combination nut and vise screw they can sell me to help me fix this five inch vise???????? since it seems near-impossible to mate a nut to a vise screw!!!!!!!!!!!! lol
   Stewartthesmith - Thursday, 06/02/11 21:17:55 EDT

Stewart : If You end up cobbeling parts to make a new screw & nut, a scafold leveling screw is a good start. You might find one of those cheap.
   - Dave Boyer - Thursday, 06/02/11 21:30:25 EDT

Stewart, You have yet to say what size? I can fix you right up with some nice 5/8" and 3/4" square thread screws and nuts from C-clamps. . . .

McMaster-Carr has matching 1-1/4 - 5 Acme in pieces 12 and 14" long and matching coupling nuts about 3" long if that's the size you need. They also have 1" 1-1/8" and 1-1/2" in short lengths.
   - guru - Thursday, 06/02/11 21:56:58 EDT

post vise nut : Nut for post vise- about 6 years ago, a blacksmith friend had the nut on his post vise come apart- the brazed in threads came apart. We decided to repair by casting a babbit nut in its place. We chose the part of the screw with the least amount of wear and coated with a good layer of carbon soot from an O/A torch for a release agent and poured the nut, The vise has been used daily and is still very functional
   - Ray Clontz - Thursday, 06/02/11 21:59:16 EDT

We did a similar thing with a spline on a milling machine spindle. Wear was causing noise and chatter, thus premature tool failure, so we added a cap to the top of the spindle and filled it with Babbitt. This helped for a while but the spine was worn with a taper which eventually forced open the grooves in the Babbitt.
   - guru - Thursday, 06/02/11 23:58:08 EDT

Anvil Rate : Whats the going rate for anvils by weight? $2.50 a pound?
   - Hayden - Friday, 06/03/11 01:42:56 EDT

Hayden, You ever hear of the 4 C's of evaluating diamonds?

Cut, Color, Clarity and Carat weight.

You can purchase grey black random shaped industrial diamonds for much less than $100/carat mounted. But a good gemstone quality diamond the same size may be $4,000 (a 40:1 difference).

Anvils are (and many other things are like that). With anvils its,

Size, Condition, Make or Material, Location and often who is buying and who is selling.

Note that age is generally not a factor unless the anvil is new with warranty or VERY old. A lot of sellers think because they have a 100 year old anvil (the most common age) that they have a valuable antique. They do not. On the other hand, many buyers have been led to believe so.

Which is more valuable per pound, a 1975 Mercedes 450 SL (sports model) or a 1975 Chevy Chevette, both in running, road legal condition?

In the past decade there have been more junk cast iron anvils sold than any other new anvils. Many were foisted off as "Professional quality heat treated steel anvils" and sold for more than $2/lb. Meanwhile you could still purchase a good (100 year old) English anvil for between $1 and $2/lb in many parts of the US. As used anvils those cast iron ASO's are worth about $0.50 or less per pound. . .

On the other hand, Hay-Budden anvils at the Parlett auction were bringing $5/pound. But these were definitely auction prices where there were too many dollars chasing too few items.

However, really fine quality old anvils are occasionally bringing $8/lb. or more.

So there is your range. $0.40 to $8. Over a 16:1 range. Not quite as extreme as diamonds.

A few years ago I bought a typical condition (a few minor edge chips, little rust pitting) 125 pound Mousehole anvil for $1/pound. I actually tried to give the guy more money. . . While it is not a perfect anvil it IS just as good a tool as one costing much much more. Tens of thousands of dollars worth of work could be turned out on it and then resold for twice what I paid for it. . . Or at least the same.

Start at what new anvils are selling for, then something less than that.
   - guru - Friday, 06/03/11 06:22:40 EDT

screw and nut : my thread on the vise I am trying to repair is inch and five sixteenths
   Stewartthesmith - Friday, 06/03/11 08:25:30 EDT

Prices on Anvils : I was at the Parlett Auction. They had three hay buddens there, ranging in weight from 100 to 150 lbs. The heaviest one went for 575 dollars, plus the ten percent vig, making the price a tad over 625. Picture two hundred blacksmiths and dealers crowding around EACH anvil, in the sweltering 95 degree heat, in the shade! And there was zero shade out there, because this was held outdoors. This is a sure sign that this craft is thriving. I even saw women and kids bidding on blacksmith tools there. Because of the size of the crowd, and the magnitude of their wallets, there were only six bargains, out of thousands of tools, all day. I landed four of those bargains. The only two bargains that got away from me were the 75 pound Fairbanks triphammer, which only sold for five hundred dollars, and the last forge of the day, a massive buffalo cast iron forge that someone STOLE for two hundred dollars. The only reason I didn't go home with those is that I came in a mini-van, and didn't have enough shocks/springs in it to transport the hammer, because my f-600 is in the shop right now getting repaired. The auctioneer changed his mind, spontaneously, on the order of the sale, and all the equipment dealers, unprepared for this, didn't get to bid on the hammer, which was an enormous break for the person who bought it. Other than that, I was thrilled with the results of the auction.................glad to see that even rough anvils commanded good prices.
   Stewartthesmith - Friday, 06/03/11 08:37:16 EDT

That 1/16" size goes to prove my proportionalism statement on vise parts. I should probably start collecting detail dimensions from as many vises as possible.

McMaster Carr has 1-1/4" - 5 and 1-3/8" - 4 Acme threaded rod.

Rod $55 / $65 for 12"
Nuts $38 / $53 for 3" long coupling nuts.

The smaller 5TPI rod would clamp tighter with less effort than the larger 4TPI rod. The larger rod would would be stronger but may not fit. The fact that the modern threads are high grade steel would make the smaller rod stronger and more durable than a larger wrought iron or mild steel part. So, in this case I would choose the smaller rod.

IF the old box is a built up (brazed together) box then I would not try to repair it. I would make a complete replacement starting with the 3" long coupling nut and arc welding pieces together.

The chances of someone having an original screw and box set to fit is pretty low. Most "parts" vises have worn out screws. I've only seen a couple vises with bad frames. One looked like someone had tried to reforge the jaws taller to make it look like a sawyer's vise and the other had the jaws cut out and a poor attempt at replacing them with modern serrated jaws welded in. . . We had a vise that the frame was sprung inward by over tightening. I put it under the hydraulic press and straightened it in no time.

Generally what people have is extra vise frames missing all the loose parts.
   - guru - Friday, 06/03/11 10:10:58 EDT

I once picked up a vise with a bad frame; looked like it had been run over by a bulldozer (and probably had!) However the screw and screwbox were in great shape.

I paid US$5 and I ended op trading it off for the 400# Trenton anvil as the fellow wanted a smaller anvil---I had an "extra" 125# PW, the repair parts for his post vise and US$100 boot. I had about $200 in that deal.

It was a YoYo anvil: Made in Columbus OH, Used at a Copper mine in AZ, taken back to central OH by the next owner and sold to me who proceeded to move it to NM.

I got two bargains at Quad-State last year. The previous time I had attended, 2 years prior, the last day I counted over a dozen post vises for around $40. Last year I noticed that $75 seemed to be the bottom price and figured I'd better stock up before they got higher and so ended up buying 2: a 6" for $50 and a 3" for $20.

Now I had to make brackets and springs for them but that's not a problem for a smith! The screws were great in the big one and acceptable in the tiny one---which is an *old* vise by it's construction and durn "cute"

My goal is to have a postvise on every work bench and utility pole of my pole barn + one free standing in a removable gazinta in the middle of the clear space in the shop, one on the welding table *and* one outside for messy work. (besides the portable demo vises).

No I don't collect them they all get used---especially when I'm teaching!

Thomas
   Thomas P - Friday, 06/03/11 12:30:24 EDT

Peter Wright Anvil : I have a Peter Wright anvil with the letter "D" stamped below the Stone weight markings. Do you know what this stands for? How do you determine the age of a PW anvil? Mine is "0" "3" "16" or 100 lbs. 45 kgs.
   Fred Foster - Friday, 06/03/11 12:41:56 EDT

Peter Wright Markings : The middle number in the weights on PW's are often inside a circular stamp that said SOLID WROUGHT. You may be mistaking some of this for another mark. However, between the feet there are often various marks of unknown purpose. They may be a forging team ID mark or inspector's mark. PW made anvils from 1830 to 1932 or so.

PW's can be generally dated by style but they did not change much. Early PW's were marked P.WRIGHT WARRANTED prior to 1952 and looked like most other English wrought anvils. Between 1852 and 1860 they were marked PETER WRIGHT PATENT and the shape became more distinct. After that they were marked with the circular SOLID WROUGHT. Then after 1910 ENGLAND was added.

There were other changes that are hard to detect that divides the 1860-1910 period. For a brief period toward the end they made a two piece anvil without a face plate. But since the plate is often hard to detect on a PW this is hard to determine in many cases.
   - guru - Friday, 06/03/11 15:07:19 EDT

Peter Wright Markings : My anvil says PETER WRIGHT PATENT, then SOLID WROUGHT in a circle, the stone weight markings are below that and near the base, between the feet, is the letter "D"., so mine was probably made in the 1860-1910 period, as you describe. Thank you.
   Fred Foster - Friday, 06/03/11 16:20:24 EDT

My Wilkinson anvil says 0-3-8 then there's another 8 below it. It weighs 100 lbs as well.
   - Nippulini - Friday, 06/03/11 22:59:04 EDT

Russian Anvil : Here is what happens to a Russian anvil after years of hard labor...

http://englishrussia.com/2010/09/17/working-with-iron-and-fire/#more-18266

Yes I know its not the same as out beloved HarborFreight Russians but it's interesting that its style is remarkably the same, But just a bigger version.
Notice its top greatly mushroomed over from lacking a hardplate maybe??
   Mikki - Saturday, 06/04/11 13:53:37 EDT

Here is what happens to a Russian anvil after years of hard labor...

http://englishrussia.com/2010/09/17/working-with-iron-and-fire/#more-18266

Yes I know its not the same as out beloved HarborFreight Russians but it's interesting that its style is remarkably the same, But just a bigger version.
Notice its top greatly mushroomed over from lacking a hardplate maybe??
   - Mikki - Saturday, 06/04/11 13:54:32 EDT

Looks like a low carbon or unhardened anvil. . But if its had as much use as it looks then "good" anvils wear out as well. They mushroom less THEN chip. . . The old man may have been doing a LOT of cold work on that anvil as well. OR they could have just been doing A LOT of work for all those years. There is a mountain of bent conveyor paddles or some sort of blade in the background that may be there to straightened. . .
   - guru - Saturday, 06/04/11 15:43:02 EDT

Champion 400 : I bought a Champion 400 blwoer this morning, I could turn it by the fan not the handle, freed it enought with oiling to turn it and let it go. It made a very distinctive noise of gear teeth missing, the worm drive gear (the brass one), was worn to a very thin edge. The machine shop quoted me $225 to make a new one. Anyone have one with a good gear I could have?
   Hayden - Saturday, 06/04/11 18:48:49 EDT

Hayden, that is cheap for a multi-start bronze worm.

The two things that wear out first in these boxes is the worm and the bearings, usually followed by the spur gears.
   - guru - Saturday, 06/04/11 19:41:19 EDT

It's not the worm drive shaft, it's the brass gear that drives it
   Hayden - Saturday, 06/04/11 20:03:41 EDT

Jock and Mikki, did you check the video at the bottom of the page? You're both right (or wrong, however you want to look at it).... He is doing cold work, but that resounding ring is NOT low carbon.
   - Nippulini - Saturday, 06/04/11 21:39:14 EDT

Russian (USSR) Anvil : Looks a lot like my 100 kilo USSR model, but wider in the face. It certainly sounds like mine! :-)

Fisher & Norris had an "export" model that looks a lot like the Russian version back in 1973*, and probably well before, the heel is just a tad longer in the illustration, so it's sort of a chicken and egg situation, was F&N imitating a Russian/Soviet bloc model, or did we send a batch of these during WWW-II as lend-lease to support Cossack cavalry? (Not so far out a theory, the Soviets were enthusiastic about adopting Western designs and technology as their own; witness Ford trucks and B-29s.

Speaking of cavalry, I really liked his riding boots and jodhpurs; proper attire for the forge, very spiffy!

* AIA, p. 190
   Bruce Blackistone (Atli) - Saturday, 06/04/11 21:59:06 EDT

The Anvil's RIng :
Steel, hard or soft rings nearly the same. Hard steel rings at a higher pitch than soft.

While cast iron anvils do not ring, there ARE many bells made of cast iron that ring quite well. The structure of cast iron makes a low frequency dull ring compared to steel. This low frequency and self dampening is why machine frames are made of cast iron.

When Tom Troszak was selling the Bull hammer. They had a video of the cylindrical mild steel anvil and base weldment hanging from a hook and stuck to make it ring like a bell. . . It rang long and loud.

The ring of a steel anvil is largely due to its shape. The two masses, the body and the base attached through the narrow waist act like a tuning fork, the vibration of one mass reflected and reinforced by the other. If you take the same amount of steel and form it into a cube it will still ring but much less loudly and for a shorter time. Even a dead soft wrought iron bodied anvil rings loudly.

The purpose of testing the ring of old anvils is to detect cracks and separated welds. A good hard steel face with a bad weld will make a dull clacking sound if struck over the bad weld. Sometimes a crack or small separation will make a buzzing sound. Bad welds in a wrought body anvil sometimes and be detected this way. You can also detect a cast iron or common ductile iron casting from steel by ring.

A good ear can detect the slight difference in pitch between hard and soft steel BUT shape is more of a factor. Hardened high grade ductile iron rings about the same as steel.

The rebound test is a better test of hardness.

THEN, as we all know, how you mount an anvil can change the ring a great deal, deadening it considerably. But you can also balance the anvil on a small surface such as a narrow stick or a high spot on the floor and it will ring much more loudly and with more sustain than setting on a flat surface.
   - guru - Sunday, 06/05/11 01:39:58 EDT

Sowhat's the verdict on the old mans anvil? My narrowest anvil doesn't ring that high... but then, even IF the face mushroomed that badly I would have cleaned it up (especially before being filmed)
   - Nippulini - Sunday, 06/05/11 11:15:21 EDT

The mushrooming says its soft. The ring may be due to how it is setting OR where the microphone was located. I have noted ear piercing sounds when sitting in front of an anvil that I did not hear standing above using the anvil.

The mushrooming can be dangerous on any tool and should be dressed down to below the cracks. Mushrooming often spalls of at bullet speeds. The resulting shrapnel can do what any shrapnel does, embed, cut, maim.

I have a number of old tools that are severely mushroomed. IF I were to handle and use these tools they would have to be cut off and dressed..
   - guru - Sunday, 06/05/11 15:25:35 EDT

Russia Anvil : Thats the main point of the topic, My beloved HF Russian 50kg is decent enough for a beginner or severe budget crisis, but as we all know, They too soft for serious professional working. My ancient no-name 300lb-er is the mainstay of my shop. My HF is carried outside for the small odd-job or let the kids practice on.

Gotta love severe mushrooming. I have several hex and octagon chisels that are curled down well over 360 degrees. The steel splits away at the exterior corners making a rather pretty steel flower. I would never use them myself, Just on display as a curiousity and to envision the hours of pounding someone done to create such bits of "art".
   Mikki - Sunday, 06/05/11 17:00:46 EDT

I've had one of those bits of "art" shot into the meat of my palm at the thumb. Not too painful, but the removal was not pleasant... nice to have a pair of vise grips handy. Another useful tool for injury is a large faced hammer....... any manageable burn? Press the face of the cold hammer on top until you can find some ice or tiger balm. Sometimes the hammer does the trick altogether.
   - Nippulini - Monday, 06/06/11 08:16:16 EDT

I've heard some horror stories about mushroom shrapnel. At anvil and power hammer die height flying shrapnel can be lethal.

Years ago dressing mushroomed tools was much more difficult than it is today. We have a plethora of fixed and portable grinders in our shops. While I do not recommend them, anyone can afford one of the little import 4-1/2" angle grinders and use it to dress tools that have become dangerous.
   - guru - Tuesday, 06/07/11 18:45:05 EDT

I don't know, Guru. Those little imported 4-1/2" Metabos are downright expensive (grin).
   Mike BR - Tuesday, 06/07/11 18:52:44 EDT

Mushrooming : I've blown HEAVY mushrooms away with the oxy 'gas hatchet' and sanded them afterward.
   Frank Turley - Tuesday, 06/07/11 20:53:59 EDT

Torch cutting works and so does a chop saw. These are necessary when the cracking has run down the shank of the tool.

   - guru - Tuesday, 06/07/11 23:07:22 EDT

hardfacing an anvil : can anyone give me some tips on hardfacing an anvil? eg: preheating and post heating times, best method of removing existing hardface with minimal risk of cracking cast and which hardfacing electrodes are recomended for this application? i have purchased a box of boc toolcraft but have concerns that it may be too brittle.
i have extencive experience in hardfacing but this time im doing a job for myself and on something ive paid for so i would like to get it right the fist time.
   greg - Wednesday, 06/08/11 03:43:35 EDT

punch tolerance : Hi all,
I'm designing a punch and die for making 30mm (1 3/16") holes in 1.5mm (1/16") aluminum. Assuming 10% of the material thickness play between the punch and the die, what should the tolerance be?
   - matthijs - Wednesday, 06/08/11 08:33:29 EDT

Greg, There are numerous anvil types and materials that must be approached differently. Unless you are manufacturing an anvil from scratch and know the material we do not recommend hard facing. Nor do we recommend weld repairs to fix chipped corners or cosmetic face damage.

While some anvils have a hardened steel plate they are not "hard faced". No commercially made anvil has been made by "hard facing".

Old anvils were made by forge welding a steel plate to the surface of a wrought iron block. The steel was of various carbon content and otherwise unalloyed. The wrought coarse and is difficult to weld to by modern methods. The plates are 1/2" to 3/4" thick depending on the size of the anvil. This method was in use up until around 1900 and many old anvils are of this type. There were many millions of these made and they may still be the most common anvil type. The face of these anvils can be welded if absolutely necessary. It is recommended to preheat to about 350°F and hard facing rods are generally not recommended. Repairs are made with E70 series or greater rods.

A few very old anvils were made of cast iron or chilled cast iron. However, due to the poor quality material these cheap anvils rarely survive. There are also many cast iron anvils made today and foisted off as "professional quality" or even "heat treated steel". We call these ASO's for anvil shaped objects. They have very limited use, are not repairable and not recommended to invest money in trying to improve.

Another old anvil type is the Fisher-Norris Eagle made by a patent process which welded a tool steel face to a cast iron body. This was done "in the mold". This was a tricky process and is generally not repairable. Heat from welding is more likely to cause a weld failure than to fix anything. When Fisher's patent ran out a number of other manufacturers started making cheaper anvils poor quality using this method.

In the early 1900's forged anvils started to be made by welding a tool steel upper body to a wrought or mild steel lower body. The face was heat treated. Exact steel types were not published. It is possible to weld repair these anvils.

After WWII most good anvils started being made of cast steel. Manufacturers kept the alloy a proprietary or trade secret as most still do today. Faces are heat treated. These can also be weld repaired but significant repairs may require expensive heat treatment. Many of these could be over hardened and tended to chip more than earlier anvils.

Many anvils made today are heat treated high grade ductile iron. These also can be weld repaired. Many cheap anvils made today are either lower grade cast steel or un-heattreated ductile iron on no specific type.

The problem with most weld repairs made to anvils is that they are unnecessary cosmetic repairs. Attempts to square up or make rounded corners square (they should be round) can produce a brittle HAZ that will fail under the heavy use anvil corners get. Spot repairs made with hard facing rod are often too hard and can develop into high spots that may damage tools. So softer is generally better than harder.

So, you start by identifying the anvil type then work from there. If you have a new anvil with a soft face then hard facing is a considerable expense that may not produce the desired results.
   - guru - Wednesday, 06/08/11 09:41:10 EDT

HF Autohammer : HF has 12v rechargable autohammers on sale $39.99. I removed the outer sleeve and tossed it. The light rapid mini blows this tool puts out is simply perfect for upsetting stock 3/16" to 3/8". When I have custom stainless nail orders, I used to use small lightweight hammers and spend a good amount time and up to 10 heats to head the stock. 3 heats and a squeeze of the trigger and voila! I will make a video and post it for your entertainment. Technically its a small handheld power hammer.
   - Nippulini - Wednesday, 06/08/11 10:02:13 EDT

Punch Clearance :
Matthijs, the tolerance is often determined by the guide system. If a machine has a tight guide system or a die set then the punch clearance can be lower than in a loose system where the punch may misalign enough to strike the edge of the die.

You also need to know that the the die, not the punch, determines the hole size. So if the hole is critical you start with the die and make the punch undersize.

The more clearance the punch has the more burr there is but the less pressure that is required to punch the hole or make the blank.

A total clearance of 6 to 10% of the material thickness (.03 to .05 material thickness per side) is standard for soft steel, brass and hard
aluminum but more for soft aluminium. For thin materials and burr free work half this amount is used (3 to 5% total). The thinner the material the proportionally tighter the clearance. 1/16" is more in the average range than "thin". So around 6% of the material thickness (total) may be right for your application (depending on some of the above variables).

The manufacturing tolerance must be a small fraction of the dimension and not let the finished dimension get out of range of the desired fit. It also needs to be within reasonable manufacturing capabilities, say +/-.001" (more if possible).

SO, your material is .0625. 6% is your optimum clearence but it could be as low as 5% and as high as 8%. Example:

0.0625 x .05 = .0031
0.0625 x .08 = .005

So there is a .002" range. Split the range and that is +/-.001" from the nominal. Diameter = 1.1844 +/-.001"

Because you do not want the punch too tight you might round the dimension to 1.1840 and up the tolerance to +/-.0015. This lets the maker be off .001 and still be within tolerance and easy measuring range. The looser the tolerance, the lower the part cost.

You can also use unbalanced tolerances such as +.000 / -.003 but this often confuses the machinist. If the part is to be ground on a cylindrical grinder after hardening the tolerance could be lower.

Also note if machining to size then hardening that many alloys grow in the process.

Punches also have angular clearance of 1 to 2° per side. But precision blanking dies may be straight. On heavy punches this starts right at the edge but each time the punch is sharpened the overall clearance increases. Punches for precision work have a short un-tapered area and can be resharpened many times. Dies also have a relief about 1/8 to 3/16" below the surface. This also limits the number of times a die can be sharpened.

Please note that my numbers above are for an example only based on limited information. Please double check the recommendations and do the math yourself.
   - guru - Wednesday, 06/08/11 12:07:30 EDT

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