Anvil face surface hardness- Lost

[Fatfudd]

Some of you may have already seen/experienced this and some of you may question what I'm about to say. I have over the years occasionally cleaned up the face of a  pitted or damaged anvil. Most just had enough surface roughness that I either used a belt sander or various thicknesses of wet/dry emery cloth to remove the surface aberrations.

Although the rebound remained the same or in cases where the roughness was really bad the rebound improved but something else also happened. The surface became noticeably softer. Slight misses with the hammer left deep enough divots they could be seen/felt. That wasn't true before the cleanup. What I'm suspecting is happening is that the

surface hardness is being removed. By surface hardness I'm talking about the type of peened surface hardness you get from the big forging hammers striking the face plate during the welding process.   This is like the difference between cold rolled steel and hot rolled.  

 

Its not that the anvil is ruined, as I said the rebound is unchanged, it just that the thin surface layer is no longer as hard as it originally was. 

 

I have seen this on enough good quality anvils- Hay Budden, Arm and Hammers and Trentons that I think this is a common occurrence among anvils that were forged.

 

If you have an anvil that has the surface planed or sanded see if you experience the same kind of response. better still if you have 2 anvils one of which has been messed with and one that hasn't see if you can tell a difference.

 

This might be another argument for not doing a "clean up" on anvil that have a rough face. 

 

I'm now experimenting with using and air hammer and planishing hammer to recover some of the surface hardness. I don't know if this will work but it is a practice used in extending the life of welds. 

See http://en.wikipedia.org/wiki/High_Frequency_Impact_Treatment

[Jim Coke]

Greetings Fatfudd,

 

I have also cleaned up many anvils with a belt sander.  Some early English ones I have found areas that were quite soft.  I have one Trenton with a spot right in the center that has a .020 indent most likely from cold forming shoes.  I would think twice about air hammers on hard surfaces and maybe look into shot blasting.  All in all the anvils that I have done they in time come back to that work hardened finish we all like ..  I have learned to use that spot in the Trenton to my advantage.  I will be watching to see how it all comes out .. 

 

Forge on and make beautiful things

Jim

[HWooldridge]

I think what you are describing is more of an appearance change from the grinding/polishing rather than an actual performance difference in the face. Typically, an older anvil will not have a planished surface unless it is already in continuous use so a hammer mark will not appear as obvious until the face is ground smooth. Over time and with use, the face becomes camouflaged again.

Most older anvils had a hardened face that was at least 3/8" thick. It would take a lot of grinding to reach the wrought iron body but it sounds like you are postulating that the face has to work harden a bit after cleanup and I'm not sure there is actual benefit from trying to achieve anything beyond what might naturally occur from normal work.

[Rich Hale]

If the hardness of the surface relates directly to rebound testing,,,and I think it does,,,if the rebound does not change the surface hardness did not change.

[Fatfudd]

As I said above- this may not make much sense but I have a side by side comparison. I have a 240lb HB that has had the face re-surfaced. I didn't do this one but approximately 1/8+in was removed. I also have a 200lb HB that has never had the top touched. The rebound on both anvils are identical but the one that was resurfaced  will show a deep enough gouge on a errant strike that you can feel it where as the other anvil shows no mark what so ever. The face of the resurface one shows thousands of small indentations and the one that hasn't been resurfaced shows none. I have used booth for many years.The anvils were made within a few years of each other. 

[MLMartin]

Anvils from the factory were not work hardened from forge welding with hammers. That is simply wrong. During the welding process the steel was so hot that the hammering done would not work harden the steel. The steel was well above critical temperature and any hammering would be stopped before it cooled to critical temperature. Also anvils were ground flat or slightly convex at the factory. This grinding would remove work hardened surface steel, Not that there was any anyway.

 

It is very likely that most anvils that have been generally used for a number of years may have a work hardened surface. But that is from smiths hammering metal on top of the anvil. 

 

Anvils for most of history were largely made by hand, even if that hand was driving a steam hammer. Hardening and tempering was done by trained people but still people none the less. It is very normal for anvils even from the same company to vary in hardness. Good company's had tighter quality control but still some tools leave the business better than others. Also with used anvils there is never any telling what the last owner did to the tool. If that person over heated the anvil some and lowered the hardness it is not a fair comparison to the same brand tool with no abuse.

 

I think it is reasonably possible that one of your anvils was simply softer than the other. Over time the softer one was work hardened from normal use, but after the surface metal was removed from grinding it exposed the softer material bellow.

[HWooldridge]

I think you'd have to perform a Rockwell or similar hardness test to know whether the two anvils are truly comparable in hardness. Otherwise, it's somewhat speculative to draw that conclusion based on appearance only. Rebound can also a subjective test and influenced by conditions other than hardness.

[doc]

I agree with both Wooldridge and Martin. Has it been considered that older anvils were usually tempered deferentially and that the closer one gets to the wrought iron under the steel the softer the temper might be? 

[Fatfudd]

Well I appreciate everyone's input! I offered this as an observation I have made over a number of years and only wanted to stimulate the discussion.

I may be right or, as usually happens, I may be way off but I'm just posting what I have seen and have actually experienced. I think everyone's response has been correct based upon your own experiences

or knowledge. It so happens that for years  I had thought that stripping away the very thinnest veneer, laid open a softer surface and as I was cleaning up a really nice Arm and Hammer anvil, I observed

the same phenomenon. I left a portion of the face untouched and went down about 20 thousandths in another section and saw a marked difference in surface  hardness between the two sections. True,

I don't have a a hardness gauge, but when one section is struck it leaves a depression and when the untreated section is dealt a similar blow there is no mark whatsoever.   

.

 

Anywho maybe others will now look at their anvils as the clean them up and see if they notice a difference. I would however admonish folks who want to do surface grinding on a rough anvil to avoid doing so if at all possible.

[Frozenforge]

I believe that the surface left behind after sanding or grinding is very on a surface finish scale full of micro peaks and valleys. When struck with another hard object like a hammer they are effectively forged smooth. You would be able to see and feel the slightest with ease.
It would be interesting to see if a piece of hardened tool steel with one part polished vs another area left as ground by 120 grit would exhibit the same apparent hardness when struck by the same hammer with the same force.

[matei campan]

could it be that, even though  the faceplate has some thickness, the hardening penetration to be less than it's thickness, as the plain carbon steel I suppose that it is, has lower hardenability...

[Eddie Mullins]

Very interesting reading. I know only enough of these things to sound foolish, so will keep any comments to myself : ) . My one and only anvil, although nice and flat does have minor pitting in the face. I have debated several times dressing it up, but have decided to refrain as my finished work does not suffer and the asthetic of the anvil is not worth the loss of material or potential performance to me. I do still find myself envyous at times of anvils with clean faces though.

[ThomasPowers]

Use will polish out minor pitting----- so get to work!

[Eddie Mullins]

Use will polish out minor pitting----- so get to work!

 

There is a shiny "sweet" spot develing over the body where I do most of my hammering.

[HWooldridge]

Well I appreciate everyone's input! I offered this as an observation I have made over a number of years and only wanted to stimulate the discussion.

I may be right or, as usually happens, I may be way off but I'm just posting what I have seen and have actually experienced. I think everyone's response has been correct based upon your own experiences

or knowledge. It so happens that for years  I had thought that stripping away the very thinnest veneer, laid open a softer surface and as I was cleaning up a really nice Arm and Hammer anvil, I observed

the same phenomenon. I left a portion of the face untouched and went down about 20 thousandths in another section and saw a marked difference in surface  hardness between the two sections. True,

I don't have a a hardness gauge, but when one section is struck it leaves a depression and when the untreated section is dealt a similar blow there is no mark whatsoever.   

.

 

Anywho maybe others will now look at their anvils as the clean them up and see if they notice a difference. I would however admonish folks who want to do surface grinding on a rough anvil to avoid doing so if at all possible.

 

I don't believe anyone is doubting the accuracy of your observations - but it just might be different root causes creating those variations.

[MLMartin]

Well said Wooldridge.

 

I was not intending any condemnation. I apologize if I came off harsh. I am just trying to correct some of the things suggested. I have experienced work hardened steel many times in my day to day work. There is most definitely a noticeable difference from something work hardened and something that is not. Even when both items were already hardened & tempered steel

[Rhettbarnhart]

Would it work to take a hardness test on the side of the faceplate below the work hardened area on each anvil?this should give you an idea of the unworked hardness of each anvil....

[Fatfudd]

Would it work to take a hardness test on the side of the faceplate below the work hardened area on each anvil?this should give you an idea of the unworked hardness of each anvil....

I agree, someday I'll find someone with a hardness tester and report back. 

[Frozenforge]

I have a tester, come on up! Sounds like not much change in weather if you got hit by that storm! Would they let you have an anvil as carry on?

[quint]

Ive been thinking about this thread for a little while. I have three anvils. A HB, PW, and a sodofors. The HB and Sodofors are both very hard anvils. They will probably chip before they dent. Now the PW which is a little more beat up and probably scene alot more use has decent hardness toward the front and back but the middle where your always striking is soft as mild steel almost. Any sort of miss hit leaves a mark or dent. Easily worked out but still always a thought. 

 

I was wondering if maybe since these guys have welded tool steel tops that it had just been warn thru over time and thus I was getting into the softer metal underneath. Not really sure as even where I can see the line it is less then 1/8" I think (hard to tell). It only has about 60% rebound but is very quiet. Would like to use it but afraid of causing more damage. Been thinking of having it repaired when I get the time money to maybe bring another 100 years of use out of it but not sure. 

[Fatfudd]

Actually a lot of the English anvils are noted for having soft bodies. More often than not I have seen PW's and mouse holes with a noticeable sway in the mid section. The American

anvil manufacturers used to use pictures of lines of English anvils with severe depressions in their centers to compare the quality of their anvils. 

You experience is the same as mine with Peter Wright anvils. 

[HWooldridge]

I've seen more than a few Peter Wrights with relatively thin faces for the size of the anvil. It's interesting to compare a 250 PW with a 3/8" face to a 1/2" plate on a 150 Hay Budden. Fishers typically have even thicker faces (and IIRC, they used photos of swaybacked English anvils as marketing literature).

[SierraBladeAndTool]

Newbie thinking outside the box... while my thinking won't create a great piece of art that will appreciate in value like a desired anvil would, it might solve a striking face issue I have seen and been curious about.    As one poster noted (HWooldridge)

... something about "Most older anvils had a hardened face that was at least 3/8" thick"...  Would one not be able to take a section of say 1/2" or 3/4" plate just slightly larger than face... harden it... invert and seam weld it to existing face... and create something gooder?  (gooder is a word in my world.)

Just thinking out loud.

*FYI... I'd center drill said plate and put a bonding plug weld midway as well so there was no gap/plate bounce.

[John McPherson]

SBT, it has been tried. And failed. The seam and plug welding was a success, but the result was not a 'lively' anvil, because there are still gaps and bounce. Your proposed method only results in a copy of a broken, delaminated anvil. 

 

What made the old anvils so great was that the entire tool steel face was bonded to the body, whether the body was a proper grade of cast iron or wrought iron. How they achieved the 100% fusion was not as important as the fact that there were NO voids. 

 

Taking a small hammer and tapping all over the face, listening for a 'buzzy' or dead spot that indicates a weld failure, is how you check out a used anvil. Even if the anvil is swaybacked from decades or centuries of use, as long as the weld integrity is intact, it is a usable tool.

 

If it is perfectly flat and buzzes, it is a candidate for a face job: cut away the damaged areas and build-up with the correct welding rods by the tried and true Gunter method. Note that building up layers of welding wire is also 100% fusion with no gaps, and can still fail after years of hard use.

[HWooldridge]

Newbie thinking outside the box... while my thinking won't create a great piece of art that will appreciate in value like a desired anvil would, it might solve a striking face issue I have seen and been curious about.    As one poster noted (HWooldridge)
... something about "Most older anvils had a hardened face that was at least 3/8" thick"...  Would one not be able to take a section of say 1/2" or 3/4" plate just slightly larger than face... harden it... invert and seam weld it to existing face... and create something gooder?  (gooder is a word in my world.)
Just thinking out loud.
*FYI... I'd center drill said plate and put a bonding plug weld midway as well so there was no gap/plate bounce.

Actually, I did something similar to a 250 lb PW about 30 years ago and it's been in regular use since then. However, as John noted, it has to be a good weld or you'll get a dead spot. In my case, I took an old trackloader flat spring, cut out the hardy and pritchel holes ahead of time, then tacked the plate to some pieces of 3/8" rod running down the middle of the face and around the holes. I used 1/8" 6011 rod to reach down inside the groove and slowly built up beads until the plate was welded all the way to the edges.

After the welding and preliminary grinding were finished, I built a temporary coal forge with a long slit for the blast. A friend of mine helped me with the heavy lifting and we slung the anvil upside down so that it was suspended over the forge. I built up a fire around the anvil and heated it slowly with a Champion 400 blower. IIRC, it took more than an hour to get it to cherry red and we kept checking the face with a small magnet to verify proper temp. We had previously filled several 55 gal drums with water and had two garden hoses ready to keep it cool after the initial quench. We brought the anvil out of the forge, flipped it right side up and commenced pouring water. About the only area that didn't get really hard was a small spot near the hardy, which has proven not to be a problem in use. The rest of the face will slide a file and has held up well since then

My avatar pic shows the anvil; you can see the unusual height between face and horn; the original face was 3/8" and the new plate was 3/4". This was a great deal of work but nobody was around to tell me it was a stupid idea so I went ahead and it turned out well in the end.

So it can be done, but you need to be really committed to the task...