Does mass added to an anvil increase efficiency?

[wooginator]

I was reading the Monster Anvils thread and I downloaded the (very useful) excel spreadsheet showing how efficiently a given size anvil returns energy when used with a specific hammer weight. What I was wondering is whether added mass, such as an anvil strapped to a stump, increases that return. If I take a 50 pound anvil and strap it to a 50 pound stump, is it the same (more or less) as using a 100 pound anvil? I feel like it shouldn't be but I'm not sure why.

[ThomasPowers]

Less as you lose energy in the interface between the two pieces---up until you strap them so tightly that they pressure weld into a single piece and wood doesn't weld to steel...

[bajajoaquin]

I think the consensus is "no."

There's a lot of material, here and on Anvilfire, about anvil construction. From all of that, I gather that it is critically important that the anvil be all a single mass in order to be most effective. Any flexibility or absorption between masses will reduce the efficiency.

[bajajoaquin]

Oh, and be careful trying to apply anything out of that spreadsheet. It was generated with simple math, based on some very high-level understandings spit-balled around a bunch of guys.

It helps illustrate the effect, but it's certainly not accurate enough to make any real determinations.

[macbruce]

I would think yes, but a 50# anvil isn't be a 100lb'er cause it's sitting atop a 50# stump........A 50# anvil welded to 50# block of steel plate the same size as the base would come allot closer to actually adding mass to the anvil.........you'd still need the stump............

If you got a 50 pounder and need a 100, sell the 50 and buy a 125.....;)

[pkrankow]

That 50# anvil strapped tightly to a 50# stump will outperform a 50# anvil set loose on a stump.

The same 50# anvil strapped tightly to a stump that is buried deep in the ground will outperform the same 50# anvil on the 50# stump.

I do not know how well the 100# anvil loose vs the 50# anvil strapped tightly to the stump buried deep in the ground would work, but I suspect the strapping will make a big difference, and the 50# anvil *may* or *may not* outperform the loose 100# anvil.

I do know that a loose 70# anvil is pretty annoying since the anvil won't stay put.

I find that a 160# anvil won't stay put without strapping either, and I am not even remotely a "human power hammer".

Phil

[philip in china]

Less as you lose energy in the interface between the two pieces---up until you strap them so tightly that they pressure weld into a single piece and wood doesn't weld to steel...

What about a stick welder?

A solid base always helps as it stops the anvil walking around the shop. If every time you hit the anvil moves slightly or the stump rocks then that is all energy which you have wasted.

[Timothy Miller]

I own a 206 lb hay-budden anvil that is drilled and tapped for 1/2" bolts. I made a tripod base with 1 1/2" solid legs and a base out of 5/8" plate. It is busted off at the prichel hole other than that it has perfict edges and superb rebound. The base weighs about 75 lbs. The improvement in the anvils rebound was significant after I bolted it down tight. It does slide around a bit but it is not bolted down to the floor. If I bolted it to the floor that is 10" thick 60 year old cement it would be even better. A good base can really help an anvil.
Tim

[macbruce]

What about a stick welder?

:rolleyes:

[Timothy Miller]

a stick welder would make a poor base for an anvil.

[ThomasPowers]

Ah yes the shtick weldor....


I have a 515# anvil as my main shop anvil. it is not securely fastened down (yet, when the new extension is finished it will be fastened to a buried stump) It used to move on the large timber balk it was on just with me using my regular hammers; but I was able to contain it with just a couple of fence staples fastened in the curve on the sides.

It's mass is enough that I don't notice the slight shifting of it in use.

[Rob Browne]

So the question should really be - does the mounting method of your anvil increase the efficiency of your anvil?

If a 500lb monster moves then a 50lb tiddler will fairly jump off the bench so securing the anvil to a STABLE base is what will make the difference not necessarially the weight of the base.

[thingmaker3]

So the question should really be - does the mounting method of your anvil increase the efficiency of your anvil?

If it is a poor method, then no. As previously noted, any mechanical energy moving the anvil or base around is wasted energy.

[Rob Browne]

My point exactly! If the 500lb monster moves you lose energy but you may not notice it in proportion to the anvil BUT a small anvil can be made to act like a larger anvil by a VERY solid mount securing system. Just remember not to hit the heel and bick too hard on a little one :)

[cavala]

So would a 50 lb anvil mounted securely to a 500 lb block of iron perform as good as an anvil of equal mass.

[macbruce]

So would a 50 lb anvil mounted securely to a 500 lb block of iron perform as good as an anvil of equal mass.

Hmmm...........:blink:

[pkrankow]

So would a 50 lb anvil mounted securely to a 500 lb block of iron perform as good as an anvil of equal mass.

Hmmm...........

Thought provoking. That is the basic concept of dies in a power hammer, so it probably would work fairly well, but a thin faced anvil won't hold up so good to heavy work. Similarly the poorly supported heel and horn would not do so good either.

A solid tool steel die that is well supported, or sized appropriately for the hammer and projection as a heel or horn would perform better.

For reference :

http://www.iforgeiro...bricated-anvil/

Phil

[ThomasPowers]

If by securely you mean a full penetration weld so it *is* a single piece then most likely so minus any effects due to the anvils shape. Otherwise there always is *some* loss in a transition

[macbruce]

My 125 PW for instance is mounted atop a 10'' sq tube fill of concrete with a 2'' x 14 x 18'' welded to the bottom......400# or so. I think it would have more umph than being on a 50# stump, but I really can't say for sure. One thing is for sure, It doesn't move unless I want it to........
Testing the diff between the 50# stump mount and and the 400 pounder could possibly be done......................
I could take say a 1/2'' sq bar, make a 1'' deep mark on the anvil to index to, take it to a near welding heat, and beat it with a 3# hammer 10 times with near equal force and measure the diff in thicknesses ................naaa....:P

[Timothy Miller]

So how about a big sledge hammer set in 200 lbs of reinforced concrete. that's 2 1/2 80 lb bags last time i checked it was about 5 bucks a bag. Make a simple wood form or one of those footing tubes You could stick a bick in it too if you wanted to.

[monty]

That 50# anvil strapped tightly to a 50# stump will outperform a 50# anvil set loose on a stump.

The same 50# anvil strapped tightly to a stump that is buried deep in the ground will outperform the same 50# anvil on the 50# stump.

I do not know how well the 100# anvil loose vs the 50# anvil strapped tightly to the stump buried deep in the ground would work, but I suspect the strapping will make a big difference, and the 50# anvil *may* or *may not* outperform the loose 100# anvil.

I do know that a loose 70# anvil is pretty annoying since the anvil won't stay put.

I find that a 160# anvil won't stay put without strapping either, and I am not even remotely a "human power hammer".

Phil

i agree my 200lb moves when not strapped down, and i am not one that hits particularly hard :P

[ThomasPowers]

Well since we are talking small differences you need a bit more rigor:
1, optical pyrometer to make sure the piece is *exactly* the same temp each time.
2, A weight supported at the same distance over the piece and allowed to free fall in the same orientation to make sure the impact is exactly the same---sort of a guillotine system would work.
3, repeat the test a minimum of 10 times with each anvil mounting.
4, publish results

Also my 515# anvil wasn't dancing in use but it was creeping.

[macbruce]

''Cold shots only''on the anvil as well. A minimum of 20 min. cooling between tests..........;)

[evfreek]

I looked at the formula on the Monster Anvils thread, and it looks like a formula for the wrong case. According to the person who came up with this formula from an introductory physics textbook, it describes the energy lost in the rebounding hammer assuming perfectly elastic collision with the anvil. This is not what happens when an experienced blacksmith is forging. According to a mechanical engineering text that I looked at, most industrial forging takes place at nearly zero restitution coefficient. In other words, the collision of hammer and target is nearly inelastic. At zero restitution coefficient, the hammer sticks to the target. At unit restitution coefficient, the hammer rebounds elastic with no energy deposited in deformation of the target. This corresponds more to the case of the beginner wailing away on cold metal. I watched some blacksmiths, including myself, and noticed that the hammer does not rebound much except for finishing blows.

So, the more relevant number is the energy "lost" in deformation for an inelastic collision. The efficiency then becomes this amount divided by the initial hammer energy. Isn't the desirable energy that which goes to do useful work on the target, anyway? Not the energy that sends your hammer rebounding up. I notice that the hammer only rebounds appreciably when I accidentally strike the face of the anvil.

Get out that physics textbook again, and do the calculation for an inelastic collision. This time, the velocity of the hammer and that of the target is equal (sticking) after collision, so there's your extra equation to make up for losing the conservation of energy equation. You have the unknown velocity and the single equation of conservation of momentum. One equation, one unknown, and it can be solved. Or, if the math is too overbearing, immediately join the CBA and get the next California Blacksmith magazine, which will have the answer, I hope.

Of course, this observation seems to fly in the face of the guru's statements at anvilfire.com, but it does seem that blacksmithing is about deforming hot metal rather than seeing how high your ball bearing rebounds.

[ianinsa]

''Cold shots only''on the anvil as well.

Ahh Vodka..... Now you're talking.

So if I follow the thought process here a 50lb anvil fixed(securely) to a 50lb stump fixed(securely) to the ground/the Earth(weight more or less = 850×5.5×1024 grams, or 4675×1024 g, or 4.7×1024 kg, or 10× 1024 lbs(or some such with heaps of zeros(noughts not Japanese planes). Gives me an anvil with a rebound similar or equal to ???????????

Well I supose as they say; in theory there is no difference between practise and theory but in practice there is!

Ian