Power hammer test

[Jose Gomez]

Thats the point. we cant all play with every hammer, and A larger head weight does not mean that the hammer hits harder. The force with which any hammer hits is directly prportional to its velocity. This means that a fast 85 pound hammer can easily hit harder than a slow 100 pounder. Unless I am mistaken that is why Mr Hofi was interested in gathering more information about the ammount of "daylight" between the dies on my hammer when the test was performed. Because if you know the Hammer weight, how many blows per minute, and the total lenth of stroke you can calculate the speed of the hammer, and therefore, total kinetic energy. The formula for this if I recall correctly is Kinetic energy = 1/2 of mass times velosity squared. The fact that you sqare the velocity is what makes it possible for a smaller faster hammer to actually transfer more energy to the workpieces than a heavier slower hammer. Hense the purpose of this test, to measure the actual effectivness of the particular hammer under full load, and to give those infamiliar with power hammers a little bit of an idea of what these machines are capable of.

[ThomasPowers]

Chris, a couple of the home-made air hammers I have seen/used seemed to hit slow/light for their stated ram weight with none of the snap I was used to from mechanical hammers.

OTOH a helve hammer can be quite heavy but not have that snap either if it's gravity powered---I've seen some real oldies in operation in several countries.

[John N]

a good test for control is removing the shell from a hard boiled egg, without destroying the inner ! - Our company used to do this on 10 ton ram double acting steam hammers!

The only way to correctly measure the energy of a hammer is either hitting a lump of pure lead of a known size and measuring the deformation, or using a velocity recorder (which we do), if you know the mass of the ram, and the actual velocity at the point of impact it is simple to calculate the energy of the blow. Assuming constants such as a 10x nominal falling weight anvil block 2 hammers from different manufacturers can be directly compared. Hammer efficency as a % can then be calculated by knowing the energy 'draw' of the motor.

Once you start to compare the difference on the forging (workpiece) of a high velocity, small ram weight blow of say 1000 ftlbs, and a low velocity heavy ram weight 1000 ftlbs it starts to get complicated!

[Chris Pook]

Originally Posted by ThomasPowers

Chris, a couple of the home-made air hammers I have seen/used seemed to hit slow/light for their stated ram weight with none of the snap I was used to from mechanical hammers.

OTOH a helve hammer can be quite heavy but not have that snap either if it's gravity powered---I've seen some real oldies in operation in several countries.

I can see that, Thats the one downside I believe the homemade style air hammers have. They are limited by how much/ fast they can move the air. A heavy head weight without larger valves/lines and more air volume is actually going to be bad for the hammers performance. The valve ports and lines are so small they just can't move the air fast enough in effect slowing/softening the blows.

The mechanicals are nice when setup that the spring actually builds force. I would have no problem believing a 100lb mechanical properly setup and tuned would out work a 100lb home made air hammer. The downside to the mechanical only being the need to reset the head height for tooling etc.

[Hofi]

JUST FOR THE FUN OF IT I MADE THE TEST WITH MY 110# 20 YEARS OLD ''SHAHINLER''
AND WITH THE 55# ''ANYANG'' NEW HAMMER.
EVERY TEST I REPEATED 3 TIMES ON COLD ROLL AND HOT ROLL 1020 STEEL 25mm SQUER .THE RESULTS ARE THE AVEREGE OF THE 3.
WHICH IS 0.985 THOU. TO START WITH.
''SHAHINLER'' 110#
5 BLOWES 0543
10 BLOWES 0397

ANYANG 55#

I TRIED ONLY THE 10 BLOWES 0545 THOU
HERE I MADE THE TEST TWICE AND GOT THE SAME RESULT
HOFI

HOFI

[steveh]

Mr Hofi,am I safe to assume that your hammer weights are in kilos?

[Hofi]

To Prevent Missunderstanding
''shahinler'' 50 Kg Is 110 Pounds
''anyang'' 25 Kg Is 55 Pounds

Hofi

[Jose Gomez]

OUTSTANDING!! Thank you, Mr. Hofi, for taking the time to try this. Your data just proved that higher hammer weight does not mean the ability to move metal faster. The 110# Shahinler was way more effective than my 155# Big-Blu. Heck, that 55# Anyang also packed the steel down better than my KA-75. It would definitely appear that self-contained hammers do hit much harder pound for pound. I also like the idea of performing the test more than once and averaging the results, seems to me to ensure much more accurate results overall. Very interesting

[mike-hr]

Thanks for the data, Hofi! I find this fascinating, I always thought that my mechanical hammer could throw a good thump, the numbers that you and J Gomez logged in show some serious metal moving.
The last week, I've been mindful of how often I run my hammer 'flat out'. Turns out, it's quite often. Reminds me of riding my half-crazy Arabian horse. Once a person gets a feel for how an individual machine performs, it goes from, "Whats going to happen?", to "How soon can we get there?"
Keep the results coming, folks!

[Hofi]

The Att Foto Show's Two Ponts I Forged Yesterday With My 110-# 50 Kg Shahinler 20 Years Old Air Hammer. From 1'' Squer In One Heat.
One Is 25'' Long
The Second Is 271/2'' Long
No Problam To Forge Even 4'' Longer
Hofi