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I Forge Iron

Power hammer test


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Made it to Quad State for the first time in a few years. Made some nails on Tom's 60 kg hammer. Clifton Ralph enjoyed it, as well as the others there to see it. As I was standing on the other side of the drive from Tom's set up, some one asked me why no other power hammer dealers were there. I pointed to Tom's set up and said because of Tom. Not one other power hammer dealer showed up to take up Tom's challenge.

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  • 4 months later...

Power Hammer Test Results
I finally got around to testing my 34 lb Rusty power hammer using the tests some of you have tried.
5 blows: 0.906"
10 blows: 0.832"
The material was 0.999 x 0.999 cold rolled steel heated to a yellow heat, but not quite a welding heat.

I also tried this test with my 66lb treadle hammer, delivering the hardest blows I could.
10 blows: 0.780"
The length of the bite was hard to control while delivering these blows, and turned out to be about 1 3/4 inches with the treadle hammer instead of 2 inches.

My "Rusty" hammer is more in the league of the 25 lb Little Giant, although the Little Giants probably run faster than my 220 blows /minute, and as a result would do more work.

I am a bit disappointed with my results; I thought it would do better, based only on my previous experience with this hammer and never having used other mechanical hammers. (Ignorance is bliss).

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I met my match when I tried to shape a broken air chisel bit into a hardy tool. The chisel was bright orange and so tough that my arm was thrown up into the air. I looked into power hammers, but they look like an accident waiting to happen. How safe are they?

Edited by bluemike
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They're not safe. Much like any of the stuff we do, they are inherintly dangerous. No distractions, keeping the work hot, using stout/well fitting tongs, and being aware of the pinch points and using common sense will go a long ways towards keeping you out of harms way though.

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For those of us with overhanging belly syndrome (OBS), learn to work the powerhammer with your tongs at the side of your body, not the center. A hammer blow that isn't flat with the bottom die can launch the tongs into the OBS, causing great discomfort, painful death, etc

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For those of us with overhanging belly syndrome (OBS), learn to work the powerhammer with your tongs at the side of your body, not the center. A hammer blow that isn't flat with the bottom die can launch the tongs into the OBS, causing great discomfort, painful death, etc


Which is a good rule of thumb anyway. Working in the center of the body prompts the user to lift up on the tongs to draw the bar under the pallets. This creates a bend in the stock. Working at the side of the body allows the user to draw long and straight tapers under the hammer.

The secondary benefit is that the continued twisting action helps with the OBS problem!
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I just did the square bar test on my 85lb. Kane and Roach mechanical hammer. High yellow heat, off the shelf a36 hot rolled, numbers are the average of 3 tests.

5 blows- .877 inch
10 blows- .721 inch

I run this hammer at 200bpm, slower than optimal for drawing but I use a fair number of top tools so need a little better control. 6.25in max. of daylight between dies when adjusted for 1in. stock.

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  • 2 months later...

Hi everyone,
great potential for a chart/ graph of hammer efficiency comparison; is one's hammer running as good as it could? I include home and factory made.

In my copy of 'Machinery's Handbook' (14th ed, 1950, p.1596-7) they explain "Heim's method for determining the efficiency of forging hammers". Basically you squish an accurately made lead cylinder (height=1.5x dia) and do a wonderous calculation that gives a foot-pounds result.

The system allows for test slugs proportional to hammer size; i wouldn't be game to smack 1" bar under say a 3cwt!

I won't add anymore yet cos i'm not sure about copyright situation and it is rather long!

Like i say a chart of peoples records would be neat for comparison of machines. I wonder (out loud) if some program wizard could develop the formula like Jock Dempsey's /anvilfire Mass 3j calculator!

bye for now
Andrew

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A couple of things:

The use of tongs with a Power Hammer is a MUST, I echo what others have said, and the "tongs to the side" is the best method.

My Rusty hammer has a 20 pound head, although I don't have the stock to do this test, this much I can tell you. It doesn't get tired from swinging the hammer, and it moves stock faster than me swinging the hammer. Yes they are dangerous, watch one run and just THINK about sticking your hand or fingers between the dies, if that doesn't scare the heck out of you, maybe you should stick to hammer and anvil. There is no really good way to guard the dies and still be able to work.

The other is on a home built hammer, you need to build guards for the moving parts, that is the next thing on my list, during the next shop session.

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  • 3 weeks later...

Ok, got round to doing the test on an 88lb (40 kg ram) Anyang 1 piece self contained hammer a few mins ago.

Hofi has already done the 25 kg (55lb) earlier in the test, and owing to a very limited supply of 1" sq I have just done the 88lb at this stage.

First off, 5 hits = .430"

10 hits = an amazing .275"

of course, as I sell Anyang in the UK you might think these results have been tweaked a little so I took a little video of the 10 hit knock down. As soon as I find the lead for the camera Ill make sure I post it here ! :D

I know James Johnson who distributes the Anyang hammer in the states has a 165 lb set up in his shop, perhaps he will step up to the plate and do the test on that? (though it might look like foil after 10 hits!!)

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Unkle Spike: I'm not sure I understand what you mean by "The use of tongs with a Power Hammer is a MUST". Here at "Tong Central" I do like to see tongs used, of course, but I still hold the piece when I can and use tongs when I have to. Usually has more to do with the length or heat of the part than anything else.

As an aside, I used to forge a lot of chisels on 5" 4340 that were around 3 - 4 feet long (these were for hydraulic hammers mounted on excavators). When the part was near done (and getting a little cold) it would often be just a little off line. It was really hard to get the operator to learn how to bang it back in line. You push it down a little so that tip of the chisel comes up off the die. Now comes the scary part: you gotta really nail it! If you try to just tap-tap-tap it down it'll flip the part across the room. After trying it that way it was a real leap of faith to get them to really hit it. They think the harder they hit it the more it will flip, right. I usually had to show them myself. The reason it works is inertia. When the hammer is traveling really fast, the part doesn't have time to flip before it's straightened. Cool xxxx indeed! Oh yeah, this was on a 1500 lb steam hammer.

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Jose Gomez: Wow, I'm impressed and proud that the KA-75 did that well compared to the Bull of twice the rated weight.

As many have mentioned, control IS more important IF you have enough power to do the work at hand. It's nice to be able to measure one to at least narrow your search. Most of the results are fairly close to what I would expect.

It would sure be nice to have these results tabulated for reference.

Grant

OBTW: I've got a 150 lb KA with a 1500 lb anvil sitting in the shed (only three ever made), got me hankerin' to drag it into the shop. Hmmm....

Edited by nakedanvil
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Jose Gomez: Well, that equation is of no use at all here. It applies to a constant angular velocity, like, say, a car going 60 miles per hour. It might be of value IF the ram was always going the same speed, but (we hope) the ram is accelerating as it comes down. Blows per minute and stroke will only yeild the average velocity and won't even do that very well if you don't know the dwell time at each end of the stroke. Industrial self-contained hammers (Chambersburg, Nazel, Massey etc) have a real "clinging blow" - they don't bounce right back up. The forging test is "real world" and pretty much measures (on a comparative basis) the terminal velocity and the anvil efficiency. That's really all there is, force and resistance.

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Heres the clip of the 88lb (40kg) anyang munching a piece of 1" sq. Its actually not that easy for me to give 10 full force blows as it kinda goes against the way I like to use a power hammer (ie gently bring the ram down, find the workpiece and build up the force of the blows as required)

Just to make things more intersting for myself the hammer footlever is about 20" off the ground (new hammer on test, so not been modified for working yet)

In the excitment I think I actually gave it 11 blows, If someone gets round to tabulating the results of this test perhaps call the .275" result .300" (the thickness of the billet reduces less with each subsequent blow)

The bar looks white hot in the video but its IR washout from the camera. It was actually light orange (subjective I know!). I would go quite a lot hotter from the gasser for welding, and it was no whrere near coke forge hot !

this is the bar after 5 & 11 hits,...

Edit,...

The dies are 2" front to back

Watch the video

14610.attach

14611.attach

Edited by John N
additional information
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Naked Anvil:

I rethought the "tongs are a MUST" rule. It would depend on the situation, and preference, let me rephrase "for ME tongs are a MUST" I generally do pieces shorter than 24", and the margin of safety tongs give are needed in my case, it prevents me from trying to "catch" a piece that is mistruck and wants to fall to the floor.

Just my rule, but I don't think a bad one by any means.

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OK, here is the numbers tallied up, best in 5 blows and best in 10 blows by order of thickness thinnest to thickest.

Best in 5 blows:
Nazel 3B
Say Mak 60KG
Anyang 88#
Sahinler 110#
Say Mak 50KG
Big Blu 155 MAX
KA75
1909 MacGowan and Finnigan "Perfect" 80#
Little Giant 25
Kane and Roach 85#
Don S's Rusty hammer 34#


Best in 10 blows
Nazel 3B
Say Mak 60KG
Anyang 88#
Sahinler 110#
Big Blu 155 MAX
Anyang 55#
KA75
1909 MacGowan and Finnigan "Perfect" 80#
Kane and Roach 85#
Don S's Treadle Hammer 66#
Don S's Rusty hammer 34#
Little Giant 25#

Some very interesting results, and I don't own ANY type of powerhammer (yet) so I would say I am unbiased :D.

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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.


Kinetic energy can be used to test the power of a hammer but is useless to test the energy transferred to the work piece. Its just like shooting a heavy bullet compared to a light bullet; although the light bullet will have a faster FPS it will do less damage because the mass is less therefor it is easier to be deflected.

Same idea with a hammer, 25lb will basically bounce off a piece of metal that a 200lb hammer would transfer a large amount of energy to.

I'll test my Fairbanks E (150lb) on Monday when I install the new motor. Should be interesting to see how it stacks up.
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