Tup to anvil weight ratio science

[macbruce]

I know of lots of opinions regarding this question but are there and scientific tables related to this subject. I've used lots of hammers that don't meet the 10 to 1 minimum (mailny Bulls) some claim is the absolute minimum and they seem to work well enough......There has to be a curve of diminishing returns regarding this, at some point there can't any advantage to increasing the ratio......How much more efficient is say; 10 to 1 vs 20 to 1 in scientific terms and how does the foundation factor in for utility hammers vs two piece hammers.....Industrial engineers must have access to this sort of data, where is it?

[Judson Yaggy]

There is a link to a Japanese study in this thread. Also there is some text on the Phonex hammer website, not sure how scientific it is.

Also remember someone (John Larson?) talking about old Chambersburg? literature where they tested anvil efficiency by measuring the squish of lead blocks. Perhaps he will chime in.

[ptree]

I understand that Chambersburg did lead block, and Massey used a speed meter of some sort to gain force values.
Frome experience a 10:1 ratio is the min i would try, 15:1 is better and 20:1 gives a real good return on investment. Been there done that on my JYH.

In industry, where everything used to be done on value, not cost, the big drop forges were generally 25:1 up to 50:1 on heavy duty hammers.
Our 25,000# Erie sat on a sow block as big as a Pickup, that sat on a 17' tall anvil, that sat on a sub anvil that was as big as a 5 ton truck and that sat on subplate about twice that big. Don't know the exact weight, we only pulled the sow block and anvil and left the other items in the ground when it came out, too heavy to lift short of the locomotive crane that originally placed it in the late 20's.

[nonjic]

Massey made 90% of their open die hammers with a 10:1 anvil. You could specify 15:1 or 20:1 as an option.

Drop hammers (closed die) were nearly all made with 20:1 anvils.

Personally I have found hammers with small anvils to be very effective up to a certain point. That point is tough, cooling, thin section material. Then you want some weight under the tup.

I have seent the 'ceco' anvil efficency chart that Jock has put the anvilfire copyright logo on. Personally I would see that as a marketing thing untill I saw the science behind it.

I have not solidified my thoughs on the size of the concrete inertia block under a hammer and any effect it has on forging efficency. My gut feeling is not very much effect on efficency after a certain point. If you study the 'elastic circuit' of a hammer mounted on concrete you will realise once the system flex has been minimised the energy can only go into the forging. Again, not based on science, but gut feeling - once the concrete is large enough to minimise vibration (which is lost energy) it is large enough.

I think most of the size of the inertia block is to prevent the block tiping and sinking over time under heavy use (caused by the very small % of energy that is leaving the 'system'' of tup and anvil as vibration).

If you look at a hammer like the closed die Banning 'ring frame' it helps with the understaning of 'elastic circuit'

[macbruce]

Thanks all, John I think I found it.......Can't use full editor, see post below..


Now this tells me (figure 1) that there is a definitely a sharp drop in returns for adding more weight to the anvil after 10 to 1 and why my 250 works pretty good even at 5 to 1........Even so, more anvil mass is in the works for that puppy.

Hmm...Seems to me that little chart could have been handy to have a few years back during a hot debate on this subject............

[macbruce]

The graph mentioned above.......

[MOblacksmith0530]

Some of the older machinery handbooks had this information in them. It is too hot to go out to the shop and look for them right now. I will try to remember to do it later.

[Judson Yaggy]

I went reading on the JSME archive today, like Don Schad said in the other thread, the paper on anvil to tup weight ratios seems to settle on a number of about 10:1. As the husband of a research scientist I understand the importance of peer reviewed research and would be slightly skeptical of charts like the CECO one on anvilfire or the one Bruce posted as both were produced by folks trying to sell stuff and neither seem to have cited their sources or explained their research. Interesting that they seem to say opposite things.

Here is the address of the Japanese anvil ratio paper. http://ci.nii.ac.jp/...=1341018106&cp=

The first thing that struck me about the Japanese paper was that as engineers do he assumed perfect conditions and the cross sectional transformation of tall rectangular stock to a shorter wider rectangular work piece. As practicing blacksmiths we all know that when you hit hot steel on an anvil it will either belly out from the center of the stock, or fish mouth out from the top and bottom. You can get a finished product with both, but we know which will be better. As blacksmiths we live in the margins of our modern world, perhaps it's fitting that the difference between a good forging and and great one is also in the thin margin of anvil to tup ratio.

Like the great Mark Asprey says, "I'm just a blacksmith." This is a wonderful discussion, let's keep it going.

[macbruce]

My graph is real similar to the one on p345 but I can't fathom the saw tooth thing they talk about on the Japanese pdf.......It seems the sweet spot is indeed 10 to 1 in terms of a good return on how much you spend on the anvil when building a hammer. Ratios between 5 and ten don't seem to measure up that bad and larger ratios do indeed drop off in efficiency quickly after 10 to 1 but there are those who will always pay for that extra umph....... B)
I there any data on foundation mass and how it might factor into the equation for a utility hammer?

[Patrick Nowak]

Keep in mind that open and closed die work are very different. Closed die is much more like forging thin flat sections so you need to get more energy into the workpiece than with open die, hence the need for high tup to anvil ratios.

[bajajoaquin]

We had a discussion about it in the "Anvils" section, and came up with the formulae that produce those curves. Here's my take on it;

For hand-hammering, it is worth while to get the best possible mass ratio, because you are very limited in the amount of energy you can put into a single blow. Therefore, there's a big difference between something like 80% and 95% efficiency.

For a power-hammer, it may be cheaper to make a larger tup, or put on more RPM than it is to design-in and purchase a larger anvil. Going from 25lb to 50lb is much cheaper on the tup than it would be going from 250 lb to 500 lb. You can just hit it a couple more times without getting any more tired.

[Sam Salvati]

But what about most of the modern hammers, Say Mak, Kuhn, Anyang, Striker, all considered to be perfectly fine and happily working away in industrial and fulltime shops all over the US and world, all seem to rely (the on piece hammers atleast) on a small anvil, they are maybe 10 to 1 if you count the foundation but not the anvil mass directly under the ram.

[macbruce]

All I can deduce from both graphs is that anything 5 to 1 and above is in the acceptable range but the closer to 10 to 1 you get the better, beyond that is a matter of preference,opinion or whatever. The hammer outfits mentioned above must have some idea of what they're doing...... :huh:

[Patrick Nowak]

The are two points to consider in this from an industrial point of view. 1-how much energy is imparted to the workpiece vs. to moving the anvil and 2-keep the anvil in the proper position relative to the tup over time. If (in steam hammer work) the anvil and foundation are not large enough, the anvil will shift and could tip, resulting in mis alignment of the top and bottom die. We had this happen at work with a foundation that was not properly installed. To overcome the mis alignment, the bottom die was machine at an angle so the top and bottom die surfaces were parellel in service. Eventually they had to take the hammer down and redo that foundation. In my own situation, the Bradley anvil/ram have a 5:1 ratio and that anvil absolutley will bounce if the bolts tying it to the frame are not kept tight.

Patrick

[Madmike]

I'd love to hear inputs from John Larson and Ken Zitur both utility hammers builders... Guys, would you jump in ?
I don't know how much of a foundation Ken's hammers need but you can throw one of John's octagons on a plywood sheet over a firm and level ground and go forging :wub:
So I am going on the 25~30:1 route as I've allready got a 3440lbs anvil and won't be able to dig in the bedrock for a foundation and I hope I won't shake the building as my smithy is under a vault :rolleyes: Planning for a 90~140lbs ram, I'll see with what I've got on hand at that time :rolleyes:

[John Larson]

Being a very long time mathematical model builder as a former professor, I am reminded of the pretty curves produced for the Club of Rome report on how the world was going to eventually end. Robert Solow from MIT ran their equations starting "at the time of Adam and Eve" and had the world come to a nasty end before recorded civilization. His point was that the curves are mere mathematical artifacts and not truly desc riptive. Some formulas have peaks and valleys in their graphs because that is what those formulas do inherently. I do not know the math being graphed and purported to be scientific proof of the mass ratioes needed for power hammers. Could be legit or might not be. The author had best intentions I am sure.

When considering the productivity of a given anvil mass you can be sure that as the ratio rises the effect will taper off. I personally disagree with the 10:1 ratio being near the top of the hill. The analogy that Tom Troszak and I have used with size of manual hammer relative to size of manual anvil is a good one. A 10 pound sledge hammer on a 100 pound anvil is not a pretty picture.

[KjZitur]

I would like to offer my opinion on this subject of anvil/tup ratio based on over 38 years as a blacksmith.
Generally, bigger is better and one should build his/her anvil to fit the intended work of the hammer and what one can afford to spend on an anvil. I would agree with John that 10:1 may not be “near top of the hill” but a 10 to 1 or 15 to 1 is certainly acceptable as an anvil/tup ratio. I think that how/where the anvil mass is positioned is just as important. I fail to see how adding weight laterally to the hammer design makes the anvil more effective, the anvil mass needs to be directly under the dies. On my hammers the anvil is placed on one end of a base plate that weighs about 340lbs. I feel I am using only about 1/3 of that mass (100 plus pounds) for my anvil, the rest of the weight just helps to stabilize the hammer. It is like comparing hand forging in the center of your anvil or on the heel of the anvil.
In regards to hammer foundations and the effectiveness of concrete as an anvil mass I will say that every hammer that I have bolted to a solid foundation just seemed to work better. I think a hammer sitting on 3 to 4 inches of concrete which has probably been poured over tamped sand, even with a high anvil/tup ratio, is going to flex that concrete and tamp the sand even more. I feel that the aforementioned 10 pound sledge hammer on a 100 pound anvil would work better with the anvil bolted solidly to a yard of concrete.

[Dillon Sculpture]

As well as the information I found on the application of wood under the anvil this book speaks about anvil weight ratios and why, both of which John and Ken concur- http://www.archive.o...ge/538/mode/2up

[macbruce]

A 10 pound sledge hammer on a 100 pound anvil is not a pretty picture.

I agree 9.5 to 1 on that one... :D .....I have a 100lb PW and just looking at it I reckon 30% of it isn't under where I'd be striking if I did elect to use it for that. In order to reach some semblance of of say 10 to 1 you need a larger anvil because the horn and heel are outside the box imo. The abundance of small anvils with busted horns, heels and cracked separated faces are very good reasons why not to get carried away doing heavy striking on a light anvil.

[John Larson]

DD, that is a very nice reference book. Thanks for sharing it I've printed the relevant chapter out and will study it more carefully.