bajajoaquin Posted October 27, 2011 Share Posted October 27, 2011 I'm hoping that someone with some knowledge of materials and math will help me out here. When we discussed "monster anvils," someone brought to the table a rough calculation of the effect of anvil mass on striking efficiency. When talking about making an anvil, we frequently talk about how different grades of steel have less rebound than a commercially-made anvil. For example, any time someone talks about buying a chunk of mild steel, Thomas comes in and says, "what about a forklift tine?" So at what point would a lighter piece of "better" material be less effective than a heavier piece of "worse" material? We can use mild steel and forklift tines if we want to limit the hypothetical. I ask for two reasons: 1. I'm curious, and I like to know how things work. 2. I'm being sorely tempted by a couple blocks of mild steel: 500lb and 1000lb that can be had for considerably less than $100 and $200, respectively. For the smaller one, I'm thinking big striking anvil. For the larger one, I'm thinking junkyard hammer base. Anyone have the equations I can put into a spreadsheet, and see where the curves cross? Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted October 27, 2011 Share Posted October 27, 2011 I don't know if we can quantify the amount of deformation of the mild item as cleaning that up every now and then seems to be in order---but with a large enough piece to start with-take less than an eighth of an inch a year off it doesn't mean much. Why I suggest fork lift tines is that they are ubiquitous; people keep saying "I can't find a big hunk of iron; I live in the city, suburbia, Gondwanaland," etc *but* forklifts are *everywhere*! They are also a good alloy and usually not too far out of shape for an anvil. Shoot I have two: a large one and a small one, in my scrap pile here in rural NM! I would love to see the break point myself; but it sounds like a MatSci senior project to me. I'll have to ask over at the University... Quote Link to comment Share on other sites More sharing options...
pkrankow Posted October 27, 2011 Share Posted October 27, 2011 Remember that a small anvil can be effectively fastened to a very large mass (the Earth) without a whole lot of fuss. Brian Brazeal's striking anvil is less than 50#, possibly including the stand in that mass. Phil Quote Link to comment Share on other sites More sharing options...
Judson Yaggy Posted October 28, 2011 Share Posted October 28, 2011 Forget the spreadsheets, if they are even close to a useful shape (cube, compact cylinder, etc.) go buy those ridiculously cheap hunks of steel! Buy them both, experiment, and if it doesn't work out re-sell as scrap, make your money back plus gain real experience. Quote Link to comment Share on other sites More sharing options...
Fe-Wood Posted October 28, 2011 Share Posted October 28, 2011 The current CBA magazine has a break down on this.... Quote Link to comment Share on other sites More sharing options...
Bob S Posted October 28, 2011 Share Posted October 28, 2011 The current CBA magazine has a break down on this.... and? Quote Link to comment Share on other sites More sharing options...
HWooldridge Posted October 28, 2011 Share Posted October 28, 2011 I don't always like Wiki entries but this one is pretty good for discussing hardness and elasticity as it relates to rebound:http://en.wikipedia.org/wiki/Hardness It does not specifically answer your question about mild steel but is still informative. Quote Link to comment Share on other sites More sharing options...
HWooldridge Posted October 28, 2011 Share Posted October 28, 2011 ...and rebound is related more to elasticity (in our world, that means 'hardness') than to mass. Case in point are cast iron ASO's - which are usually squarish and blocky. They should rebound the hammer but don't in practice because their faces is soft - and not due to lack of mass. Best anvil I have ever worked over was a 300 lb Hay-Budden. It had excellent rebound and was a real joy to forge on. I initially thought that was primarily due to mass but there was almost no rebound on the table or horn, which were soft. I once tried to file a couple of bumps on the edges of the face and it slid a sharp file with no bite at all - so it was probably pushing north of 60-65 RC or thereabouts. In addition, my longtime demo anvil was a 100 lb Hay-Budden and it rebounded almost as well as the big one - it also had a 100 lb stand under it. So...although I cannot readily provide the stress curve table you requested, I can say from experience that any anvil with a hard face will rebound better than a larger mass of mild steel or cast iron that is relatively soft. Quote Link to comment Share on other sites More sharing options...
Fe-Wood Posted October 28, 2011 Share Posted October 28, 2011 and? I haven't finished the article so I don't have any insight I left it at the shop :( Quote Link to comment Share on other sites More sharing options...
bajajoaquin Posted October 28, 2011 Author Share Posted October 28, 2011 But you did just remind me that I haven't been getting my CBA newsletter recently. Hmmm. Thomas, that's an interesting comment. I've read your comment about tine when people mentioned a tool steel face before, but I always associated it as much with the alloy as the availability. Interesting. I didn't read the Wiki article carefully, but in scanning, it appears that we're looking at a combination of elasticity and rigidity, which provides "rebound hardness." A plastic deformation would absorb the energy of the blow, and a non-rigid, elastic deformation would not transfer energy to the work piece. There's something else going on, with the way different materials tend to absorb or transmit shock or harshness. I know I'm not using the right terms, but I don't know what the right ones are. You know how an aluminum framed bicycle can feel very stiff and precise, but a little "dead" compared to a steel one? So I'm still going to go and see if I can get this 3,000 lb of steel block (two 1k and two 500lb) for a deal, because... why not? But I'd like to understand the best way to use it, and why. Quote Link to comment Share on other sites More sharing options...
SoCal Dave Posted October 28, 2011 Share Posted October 28, 2011 The July issue of the CBA magazine has an article on anvil mass. It discusses hammer size vs anvil size with included mathematical equations that might help. Near the end of the article it does mention "having the anvil tied to the earth". So even with a large anvil, the base it sits on is important. Quote Link to comment Share on other sites More sharing options...
evfreek Posted October 28, 2011 Share Posted October 28, 2011 Hi.Dave. The article in the CBA magazine is a good start. There will be a few more articles in the series, and the second is coming out in the next issue. If you are interested in more technical details, the full version is available on the website. It is a little bit heavier sledding, though. Quote Link to comment Share on other sites More sharing options...
Frank Turley Posted October 30, 2011 Share Posted October 30, 2011 Keep it simple. Look for a good anvil with a hard face, and use a good, stout stand or stump for mounting. Lots of work is done on anvils weighing 160 pounds or more. It depends on what you are doing. As for the big chunks of steel, as suggested above, buy and resell, or let 'em go. Some ball bearing rebound tests are listed on anvilfire.com; FAQS; anvils. There is a pull down menu. Quote Link to comment Share on other sites More sharing options...
Timothy Miller Posted October 30, 2011 Share Posted October 30, 2011 I agree with frank no need to reinvent the wheel. I would buy those blocks of steel though because they are a good value. Get a real anvil and get to work forget about workarounds and substitutes there is nothing like the real thing. Once you get a good anvil you will wonder why you didn't get it sooner. I have almost never regretted buying good equipment. I have often regretted buying stuff for projects I never got around to do. Upon refection I found a lot of that stuff was really just junk. I found, I often lacked the time, equipment, skills or experience complete the project to my satisfaction. That's not to say don't push your self to learn new things. But I would say put your time to increasing your forging skills. Quote Link to comment Share on other sites More sharing options...
Bigred1o1 Posted October 30, 2011 Share Posted October 30, 2011 if one of those pieces of steel is a slab i can just imagine having one heck of a worktable Quote Link to comment Share on other sites More sharing options...
bajajoaquin Posted October 31, 2011 Author Share Posted October 31, 2011 Oh, don't get me wrong, I have a "real" anvil. A nice 185-lb wrought. I was hoping to understand the relationship between hardness and mass as it related to work efficiency. It was a "why" question rather than a "what." Quote Link to comment Share on other sites More sharing options...
Timothy Miller Posted October 31, 2011 Share Posted October 31, 2011 I think the relationship is over stated because most of the time you are beating on soft glowing iron. Its only when you strike on the work cold or directly on the anvil face that rebound really comes into play. Quote Link to comment Share on other sites More sharing options...
Bigred1o1 Posted October 31, 2011 Share Posted October 31, 2011 i think you are mistaken Shoushoresmith bc the rebound in the anvil is pushing back up into your work as you strike it from the top to the better the rebound the more movement you can get per blow of the hammer Quote Link to comment Share on other sites More sharing options...
bajajoaquin Posted October 31, 2011 Author Share Posted October 31, 2011 When we were talking about the relationship between mas and efficiency, Maddog gave us this equation: "The equation I used was %Energy loss = 4r /(1+r)^2 x 100 where r is the anvil to hammer mass ratio." From there, I think we were able to get an understanding of the improvement in performance as anvil mass went up. What I was hoping to do here was work out the next order of sophistication, the relationship between mass and hardness. If we do a little thought experiment, we can see that a 5lb block of tool steel will make a much better anvil than 1,000 lb of foam rubber. That's a silly example to show that we can presume hardness is part of the function, not just mass. Because of the huge difference in material properties between those two, when I gave my "for instance" above, I tried to limit it to some more similar materials, so as to help minimize the variables. Perhaps Thomas has had a chance to speak with someone at the university...? Quote Link to comment Share on other sites More sharing options...
iron woodrow Posted October 31, 2011 Share Posted October 31, 2011 probably a similar way of looking at it is that we dont use mild or wrought as a hammer, no matter what mass, because the difference is apparent even before use! could an experiment be done on a block of carbon steel with a large mass, try it when normalized, and try it when hardened. the difference will be very noticable, with the same mass. and im not suggesting anyone normalize their anvil! not all reactions are created equal it seems, isaac newton . Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted October 31, 2011 Share Posted October 31, 2011 Actually I talked to one of his Grad-Students Sunday; he's currently has 97 student's in the class he's teaching and is swamped---they've had a hiring freeze but keep losing staff especially as the workloads go up and the salary *doesn't*. I'll talk to her again and see if she knows a grad student we can rope in.... (btw my students love my dead soft french pattern crosspeen. I believe it went through a fire; but they sure do a lot of work with it anyway. About time to dress it again though...I love it in that they can't ding my anvil or mess up hardy tooling with it.) Quote Link to comment Share on other sites More sharing options...
Bigred1o1 Posted November 1, 2011 Share Posted November 1, 2011 woodarmourer that is just a perfect solution i am going to have to keep an eye out for a good block of steel to try this with just out of curiosity Quote Link to comment Share on other sites More sharing options...
Nakedanvil - Grant Sarver Posted November 1, 2011 Share Posted November 1, 2011 Here's what I know: Hard is better than soft, big is better than small. I don't need to know more. Quote Link to comment Share on other sites More sharing options...
Timothy Miller Posted November 1, 2011 Share Posted November 1, 2011 If the material is always hot it is softer than the anvil face. If you are not deforming the anvil face that energy going into the anvil is moving the anvil slightly and going back into the work piece. I don't see how a soft anvil is a problem if you only beat hot iron on it. Silversmiths frequently work on cast iron stakes if the hammer never touches the stake there is no problem. The only real problem is that in the long run scale is abrasive and it will ware the softer material faster than hardened steel. But most of us do beat on cold material and allow the hammer face to bounce on the anvil face from time to time. and this will deform an unhardened steel block in short order. I don't see how a hard anvil face is contributing to the hammer rebounding when one is forging a hot ferrous material that is soft. Its like kneading dough on wood counter verse a granite counter the dough will move the same because both surfaces relative to the dough are hard. Quote Link to comment Share on other sites More sharing options...
HWooldridge Posted November 1, 2011 Share Posted November 1, 2011 If the material is always hot it is softer than the anvil face. If you are not deforming the anvil face that energy going into the anvil is moving the anvil slightly and going back into the work piece. I don't see how a soft anvil is a problem if you only beat hot iron on it. Silversmiths frequently work on cast iron stakes if the hammer never touches the stake there is no problem. The only real problem is that in the long run scale is abrasive and it will ware the softer material faster than hardened steel. But most of us do beat on cold material and allow the hammer face to bounce on the anvil face from time to time. and this will deform an unhardened steel block in short order. I don't see how a hard anvil face is contributing to the hammer rebounding when one is forging a hot ferrous material that is soft. Its like kneading dough on wood counter verse a granite counter the dough will move the same because both surfaces relative to the dough are hard. The iron doesn't stay in a bright yellow plastic condition so you start getting resistance/rebound as the material cools. Silver and gold are soft at room temp and generally worked in that condition - so is bread dough. I agree with your comments about scale but if cast iron anvils were the epitome then that's what all of us would use. Quote Link to comment Share on other sites More sharing options...
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