Why is rebound important?

[BartW]

Hello;

 

Well actually i did that experiment a while ago.  I took all my anvils; cleaned & polished them. On each I put a slab of copper(about 2 x 2 x 0.5 inch), same thickness, cut from the same bar. I took a 50mm (2inch) ballbearing, and dropped it from a meter high on the copper plate on the center of the anvil.

I couldn't detect a difference between anvil hi-end anvil (solid tool steel vs tool steel face plate). My iron swage block had a noticeable smaller dent, even compared to a railroad track. A piece of cast iron was about the same as mild steel, I didn't have a cast iron anvil.

Now, my opinion is that rebound Does matter, but the difference is extremely small. You will save 1 or 2 blows out of 100 hammer blows, but that's it. And if you stay in suitable anvil teritory you may save one blow in 200 by having better rebound, so does it matter really ? Well yes, but not much.

 

[JHCC]

That's very interesting; thank you. 

However, in the "are you testing what you think you're testing" department, there are a couple of unanswered questions. First, was your copper bar an appropriate stand-in for hot steel -- that is, do they both have the same malleability? Was the copper annealed before the test, or was it still work-hardened from the rolling process?

Theoretically, that shouldn't make a difference in comparing the difference between anvils, as the difference in malleability between copper and hot steel is (presumably) known and could be included in the calculation. However, performing these tests on a softer material might accentuate the differences between anvils.

This raises the second question, which is, how are you measuring your results? It's one thing to look at a series of dents and say "There's no appreciable difference between these", and very much another to measure their depths with a dial indicator or the like. The variations might be too small to be observed with the naked eye, but much more apparent with a more sensitive measuring device. 

[anvil]

Rebound has little to no effect on your forging. Rebound indicates the quality of a cast anvil. Meaning no voids in the casting. If you have a high carbon face welded to a wrought iron body, it indicates the quality of the weld.

The single most important item is the connection between anvil and stump/stand and the connection between stand and ground. I prefer a wooden stump buried ~3' in the ground. I was a full time farrier for quite a while and there is a world of difference between my 124# farrier anvil sitting on my metal stand which sits on anything from road to, well, second hand well dried hay and any of my shop anvils securely mounted to stand and ground.

When I'm in someone else's shop and using their anvil the first thing I notice is anvil height. However it is easy to overcome. Second is vibration from how the anvil is connected.

Why is an ASO  or a large piece of mild steel a poor choice for an anvil? Pretty simple, over a very short time of use, the face and edges will ding or chip quickly and these will show up in your work.

[FlatLiner]

From what I am understanding Anvil, the reason for the hardened high carbon steel plate or cast steel anvil is more for wear/longevity with the side affect of great rebound and slightly better forging characteristics.

[foundryguy]

On 4/21/2020 at 10:05 PM, Benona blacksmith said:

Absolutely not. Cast iron ASO's are dangerous as is an anvil that's too hard.  A piece can fracture off and hurt someone badly. I dont even like my 250 lb cast iron swage block for the same reason. My buddy got hit in the chest with a piece of my swage block. I much rather use my Holland anvils swage black that's a ¼ the weight.

You need to visit us in Holland sometime, we have a lot of new things going on

[basher]

On 4/21/2020 at 8:26 PM, ThomasPowers said:

Basher; do you notice the difference between using a 100# anvil and say a 400# anvil?

I can feel the diferences between my smallest anvils (150 or so) and a 200 especially when working off center on the anvil ,  200 and up not at all ,  i have a good range all the way up to 900lb..... all this with a hand hammer of course. I have anvils I prefer but that is basically more to do with face geometry , the way the edges are ground etc. I regularly (pre lock down!!!) use 12 different anvils whilst teaching classes and am happy with any of them.

I am however very partial to a beautiful anvil!!!

There is a lot of stuff written about the ring and rebound of an anvil being all important and the ring is a huge pain in the ear and rebound is of little or no importance to me in my work.

 

[Benona blacksmith]

On 4/23/2020 at 12:47 PM, foundryguy said:

You need to visit us in Holland sometime, we have a lot of new things going on

I would enjoy that. I will set up a time after all this corona stuff.

[jlpservicesinc]

On 4/22/2020 at 12:40 PM, Buzzkill said:

When tens of thousands of people who use a tool all day every day to make a living are willing to pay up for a specific feature it's a pretty safe bet that there is at least as much benefit as there is cost to that feature.

The reason for the steel faces on wrought iron anvils was to slow down the level of compression of the wrought iron..    

Well one of the reasons..  Wrought iron compresses like no one can speak about..  It is about as soft as aluminum when put into hard work. 

The steel face did many things for the anvil..  The main one increasing longevity because that simple layer slowed down the compression factor. 

Most wrought iron was first run used in anvils and  was considered lower grade.. Peter wright used to sell a 1st quality made from new wrought iron and a premium made from scrap.. 

I have found that the largest factor in forging fluidity and work done per heat is all about the amount of square inches that one is effecting. 

Forging heat is the largest factor overall X square inches X amount of energy applied.  

I'm not going to get into arguments about equations and such.    

I have found that the shape of the anvils face plays into how fast the iron will move..   this comes back to nibbling the material as a crown to a face it more effective when moving metal vs a completely flat face. 

i own several different makes and find the I like to forge on my old Hay budden the best. 

[Buzzkill]

No argument from me at all.  What I was pointing out is the nitpicking over rebound, mass, etc. is somewhat immaterial to me.  Obviously the change to hardened steel tables was worth it to the people who used hammers and anvils every day for a living.  I've found blacksmiths to be among the most frugal people I've met or talked to.  I have a hard time believing that thousands of blacksmiths would be willing to pay up for a feature (hardened steel table) unless they were absolutely convinced they could be overall all more efficient with that feature - it would have to pay for itself.  That's all I really need to know.  Like Thomas Powers pointed out elsewhere there are some really interesting theories about how heavier than air flight is impossible and that makes for some great in flight reading.    In this case I believe that the experience of thousands of people trumps the theories or musings of the few.

Only somewhat related, I once got into a discussion about the energy return on investment (EROI) for various proposed "green" solutions.  The person I was discussing this with asked why no one ever worries about that with oil.  My reply was that we have over a hundred years of proof that you get more energy from a gallon of crude oil than you have to expend to get it. I never felt the need to calculate the exact EROI for oil due to the overwhelming evidence that we get significantly more energy than we have to expend to extract it.  I feel the same way about this.  For whatever reason, be it rebound, resistance to deformity (which means less absorbed force), etc. it was important enough to expend the time, money, and energy to add it as a feature compared to a softer surfaced chunk of iron or steel. Of course we *can* forge on rocks, cast iron, mild steel, or a number of other surfaces, but there are good reasons hardened tables became the standard or I can't see frugal smiths paying up for them.

[jlpservicesinc]

Sorry, I wasn't directing it at you..  What you wrote is kind of a common belief so it was more an informational post vs an "At you".. 

Personally I feel that the steel to cover the wrought iron was the only way they could get a long enough duration use out of the anvil vs the non faced. 

If you figure labor is the largest expense the materials once they got to a certain point did get cheaper..  it makes sense to expidite a longer lasting product as the overall expense is less to steel it rather than not to. 

Forged steel and later cast steel became the norm as technology took over and labor being as expensive as it was was nearly cut in half compared to how much time it took to prep the wrought iron and then apply the steel. 

Anyhow.. It's all fun..  Historically what if, or such.. 

 

[Buzzkill]

Sounds like we're mostly in agreement.   When everything is taken into account there has to be enough benefit to justify the expense or people just won't do it - at least not many people who use something all day every day to earn their living.

If you wear work boots 12 hours a day 5 or 6 days a week you may be willing to spend $300 or more on a pair.  You can certainly buy much cheaper footwear, but when you use something every day all day the difference in quality and comfort become apparent as does your fatigue level, foot pain, and even back pain.  If there was only an insignificant difference between the cheaper boots and the more expensive boots in daily use why would you buy the more expensive pair?  It's the same principle in my opinion.

[ThomasPowers]

Of course frugality today does not have to equate with frugality in previous times.  Many smiths rode the curve down to where only the frugal could survive and profit. If they were the ones you talked with then others who lived in times when smithing was considered a high paying core skill you might get a different viewpoint. (There are several examples of a smith being so poor when he died that they used his anvil as a headstone, also indicating that the value of anvils had dropped as well).

Sort of like the changes in social standing of the smith: early in the iron age the smith was considered an important person having a direct connection to various gods.  In the Irish legends;  Chulainn the smith invited the king to come eat at his table---and he did, (Cú Chulainn got his name from an incident that happened there.)   As time went on and iron and ironworking became more common the role of the smith was seen as a top level craftsman as seen in the Medieval and Renaissance craft guilds and then as a standard worker type of jobs as factories often employed hundreds of them. (Why "Was it hand forged or factory made?" can sometimes be answered with a "Yes").  As Mechanization took over in factories, the status of the smith decreased until it rose again with a role in artistic endeavors with such Smiths a Yellin

[anvil]

Nice piece, Thomas, and I pretty much agree with you up til your last sentence.

Before Yellen, you must also consider the contemporary pathway of industrial blacksmithing. What industrialization and mechanization did for industrial Smith's was to harness incredible amounts of power. Just look at the many huge contemporary forges and hammers to work and forge massive pieces of iron. And, the techniques to do so have not changed. To draw out a shaft of many tons from a billet, it's still forged square, octogon, round. I would go so far to say that the contemporary industrial smith  is still the "King of all crafts" and is the tool maker for all. Imagine computer chips without the abilities of the industrial Smith.

Back to Yellen. He did in no way 

7 hours ago, ThomasPowers said:

rose again with a role in artistic endeavors with such Smiths a Yellin

He in fact at his moment in time stood at the end of a long line of architectural Smith's that preceded him back far beyond the Gothic period. He, and "traditional architectural Smith's", of our day, may have been during a time of being "badly bent" in the US, but not so in Europe. Architectural smithing in Europe has always been strong. At the very least, Europe has always had a need for qualified Smith's to do restoration work of all kinds. The trail of architectural iron in the US, even as young as we are compared to Europe, is vibrant from the earliest time of our history to the day. 

Lol, basically I believe that if one wants to make a living as a "blacksmith" in our contemporary time, there are three basic choices. Industrial smith, architectural smith, farrier. 

 

[ThomasPowers]

Well the days where *every* factory had at least one blacksmith & helpers as part of the maintenance shop has ended and now just a few factories support smiths.  I've met smiths that have worked at places like a Sugar Refinery, glass factory, shoot even one who worked in a Hospital during WWII. Nowadays only a select few places have one; none of the factories I worked in did!

I was rushed in the completion of the previous post, sorry. There was a Parallel path of "Artistic and Architectural" smiths in the late 19th century and into the 20th, (and earlier).  Often tied with various artistic trends, (Neo Gothic, Art Nouveau, Art Deco). Folks like Edgar Brandt for instance.

I managed to get permission to take a picture of the ornate hinges at Neuschwanstein after explaining to a guard in my high school German, (from 20 years past); how impressed I was with them and that there were no pictures in the gift shop of them. 

However my thesis was that the smith's industrial role gradually changed from being a focal point to an ancillary, nowadays often taken over by welders. But in the artistic arena a few smiths still flourished and were lauded in their endeavors---the inheritors of Jean Tijou in modern times and even today the name Albert Paley comes to mind...

Gotta run! (Or we could discuss the role of Folk Arts in the Nationalism of the 1920's and '30's and how it affected smithing.)

[anvil]

I just got in from working on my shop and I'm whipped! It doesn't take much anymore! Thank goodness for young labor.

I would enjoy a discussion with you anytime especially on this aspect of our craft. I'm from an engineering background,, 2-1/2 years before I chose my iron path. Coupled with a bunch of years as a farrier it took a long time to figure out such terms as "artist blacksmith" and how I fit into that strange thang. I think it was a long ago article in the Ring by, if I remember correctly, Pete Renzetti, or one of the true art Smith's of that era. He broke art into 3 parts. Fine art, applied art and commercial art. The utter simplicity of it has been with me ever since. Fine art had one primary purpose. That is to create an emotion. Applied art had two primary purposes. To create an emotion and it must have a function. If you build a "WoW" gate, it should at least be able to some degree keep the dog In and the bad guys out. Thus began my acceptance of me being an Applied Artist. I put the crafts in this catagory as well. My next major learning was a workshop in Prague with Vaclav Jarosh in '87. He demoed at Flagstaff in '86 and critiqued American Smith's as strong in technique and very weak in the art history of our craft. Thru ABANA he created a workshop for 10 smith's in two different groups. He called this Art history for the Architectural Blacksmith. We covered all art periods and made tooling and a representative samples from about 9th century to contemporary. A lot to cover in a month, to say the least. It was a major influence on me. Lol, I'm pretty tired, so will end by saying my knowledge fits well with " in the kingdom of the blind, the one eyed man is king" concept. I'd never attempt a stand-up discussion with a first year art history major, but I do have a bit of knowledge as to what blacksmith details are from what period. I'd share Prague iron pics with you here and love to see yours as well if there is any interest.

[JHCC]

That would be great. You should start a new thread. 

[Irondragon Forge ClayWorks]

I agree a new thread is in order, I would be interested and follow it.

[jlpservicesinc]

I also agree.. Please do start an  "Anvil" thread, and show us more photos with stories..:) 

[anvil]

Ok, I'm not much for starting threads, but will do. 

Shops coming to conclusion and then the "big" sort thru slides, negatives, and pics.

[jlpservicesinc]

Anvil, that is exciting..  Can't wait..  I hope you took plenty of photos of the shop build too..  That could be a great top off. 

[Marc1]

On 4/21/2020 at 11:47 AM, Latticino said:

Couple of interesting videos posted on this subject, that I haven't gotten the chance to watch in great detail yet.  The one by Daniel Moss seems a bit more rigorous (the first one):

Thank you Latticino for posting this videos. I had seen them before and they both have value. 

If you are interested in the various myth around anvils, like the value of ball bearing test and the value of a good stand or ground, I suggest to watch both and comment on them.

My take goes as follows. 

Ball bearing test is useful to test the material the anvil is made of. More bounce, harder surface. Not much to debate there. 

Paraphrasing a couple of claims made in the first video:

"The blacksmith is more efficient on an anvil with better rebound."

Considering that the efficiency in question is completely subjective, it is impossible to detach the bias of the said blacksmith who knows in advance the anvil he is using, from some minuscule if even measurable difference. Still, we must concede that the worker must be happy with the tool he uses. If he says this anvil makes his job easier, then that is what it is. 

But we can not make a religion of it. Yes, there are some force losses into a softer anvil, I question if such losses can even be measured. But for argument sake, be it placebo effect or not, I settle for ... an anvil with more rebound will make working on it that little bit easier. 

second claim:

"After observing how the stand sinks in the mud, it is obvious that some force from the hammer goes into the stand and the ground ... therefore ... a concrete floor, a better stand or both will increase the returned force from the anvil into the work. " or words to that effect ...

Unfortunately here we part company. 

If the stand mass is part of the anvil mass, why do we buy different size anvils? Stands are cheaper by the kilo. Buy a 20 kg anvil and make a 200 kg stand and you are saving heaps!

And the ground? Why don't we drill down to bedrock and pour concrete in the hole and call our anvil one that is the same mass as the earth ... or at least the continent we are standing on? 

Well I am exaggerating to make a point. Both ideas that stand and ground make any difference to the anvil effect, is missing the basic physics of collision that is at the heart of how an anvil works. 

Yes, there are losses when you hammer an anvil and those losses go in part into the base and the ground, but the important part is that such losses are gone forever never to return as soon as they depart the legs of the anvil. 

Second video, 

Claim: rebound is horse poo, worth nothing since the demonstration with plasticine shows the hammer does not bounce off plasticine on anvil or plasticine on wood. No difference. 

Well ... I said before that the so called rebound or rather return from the anvil is very small and more subjective than anything, but the plasticine demonstration is worthless. We don't forge plasticine, we forge hot steel and if you have ever done this just once, you know very well that the hammer DOES bounce off hot steel, even if it is white hot. 

So my take is ... Test your anvil before buying with a ball bearing. After all you have nothing else to test it with. 

Use the right size hammer to anvil ratio and the right size anvil to work size ratio. 

Consider your efficiency more in line with your skills and endurance than the rebound of the ball bearing.

By all means build a proper sturdy solid stand and anchor your anvil down properly, but don't think for a moment that you are adding mass to the size of your anvil because you are not ... unfortunately. Fortunately for the anvil manufacturers who would otherwise be relegated to make 20 kg anvils to be bolted to 200 kg concrete blocks.

[jlpservicesinc]

Well said and expressed Marc1..     There are many variables for sure and one that is also not mentioned much is face geometry.  I personally don't like a flat fact but raised in the center..

Not sure how it happened thought I have read that Hay Budden anvils have  a crown to the face, My 175lbs had a crown and I like that better than any other face I have worked on. 

Here is a "bounce" rockwell HRc tester..  it is and interesting tool and it has not been calibrated or verified but seems pretty consistent with what it should be.. I have not setup my commercial indenter rockwell tester to confirm the accuracy but going by what a material should be in testing and comparing the results. 

the Refflinghaus anvil is 64 Rockwell HRc in this test.   I also tested the center of my  5160 Wrought iron hammer and it came out 60HRc and edges were 54Hrc.  I do a radial temper. 

 

Here is the hammer test. 

[Marc1]

17 hours ago, jlpservicesinc said:

Not sure how it happened thought I have read that Hay Budden anvils have  a crown to the face, My 175lbs had a crown and I like that better than any other face I have worked on. 

True, but I believe it was more to compensate future subsiding of the face then improving performance. 

Crowned face is better than sagging face, however you hear people saying they like a bit of a dip on their face. I rather have a flat or crowned one any time ... 

We are talking about anvils right?

 

[jlpservicesinc]

It might have been a sales ploy whos to say.   It was deliberate..  they had moved to a 2 piece design at that point so sagging faced because of wrought irons compression factor was a thing of the past.  I now wish all anvils had a larger center crown. 

20 years of heavy daily use left it with no change at all. Anvil abuse was abound. 16lbs sledge used upon her stature weekly.  Only when I came out of retirement did it get it's first abuse with a few missed hammer hits. 

and yes, I do believe we are talking about anvils, though sir now you may have me question..     One time at band camp......   I do love smush faced dogs especially boston terriers. 

Oh and vintage SAAB automobiles. 93 or 96 snub nosers. 

[ThomasPowers]

"A scleroscope is a device used to measure rebound hardness. It consists of a steel ball dropped from a fixed height. The device was invented in 1907. As an improvement on this rough method, the Leeb Rebound Hardness Test, invented in the 1970s, uses the ratio of impact and rebound velocities to determine hardness." Wikipedia

Works best on smooth flat surfaces.

I like some dip on the anvil I straighten blades on.  I find it doesn't affect my forging of them much.  Personally I like forging on the quite broad horn of my large fisher to draw out steel which is very much like the asian  crowned anvils in that usage.