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Hand Hammer / Power Hammer Equivalents


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Is there a rough rule of thumb for comparing the two?

 

i.e. I do most of my forging with a 6lb hand hammer, if I want a power hammer that has about the same impact force (but higher rate) how would one figure that out?

 

Thanks in advance,

Ben

Ben Potter Bladesmith

 

 

It's not that I would trade my lot

Or any other man's,

Nor that I will be ashamed

Of my work torn hands-

 

For I have chosen the path I tread

Knowing it would be steep,

And I will take the joys thereof

And the consequences reap.

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The basic formula should be M x V = F (Mass x Velocity = Force).  The real question has to be, why would you want as little force as a hand held hammer, but faster.  The whole point of a power hammer is more power than you can generate with just your arm.  Some sort of treadle hammer or a grasshopper might be what you're talking about.
 



 

"The worst day smithing is better than the best day working for someone else."

 

I said that.

 

If a thing is worth doing, it is worth doing badly.

- - -G. K. Chesterton

 

So, just for the record: the fact that it does work still should not be taken as definitive proof that you are not crazy.

 

Grant Sarver

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In my experience, the BPM of the power hammer makes a bigger difference than the head weight with sub-100-lb mechanicals hammers and sub-150lb air hammers.  Mechanicals seem to move metal better than pneumatics for a given tup mass, since they have an inherent "snap" from the springs that accelerates the tup faster than an air cylinder can move.  Self-contained air hammers hit harder than utility hammers due to the decoupled nature of the two cylinders allowing that same spring action on the stroke.  That's why a 33lb Anyang outperforms a 50lb Kinyon-style (original design, there are refinements to the valving that work better) hammer.  

 

Geoff is correct. F=MV, and the V of your six-pound hand hammer is going to be faster than the V a power hammer tup can achieve.  Hopefully John N will chime in on this, he's got test results from studying this very thing with Massey power hammers, unless that data got lost in the fire.  My 50lb mechanical hits about as hard as a 10-lb sledge swung by a good striker, but at 220 BPM.  

 

I think you'd be happy with any power hammer, though.  They're all faster than doing it by hand.  Even a 25lb Little Giant will move steel faster than the biggest hammer you can swing by hand.  

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20 minutes ago, Alan Longmire said:

F=MV

Not in the physics texts I remember.  F=M x A (mass x acceleration).  You may be thinking of Kinetic energy: Ke=1/2 (M x V squared), or momentum(P): where P= M x V.  The latter is the equation that is often overlooked and I believe more applicable to the plastic impacts we see in forging of hot steel. 

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Ultimately most power hammer will give you fine control so that you can hit soft or hard blows. To quote James Johnson from Anyang: large power hammers can do what smaller ones can, but small power hammers will always be small. 

Edited by Francis Gastellu
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Thanks all.

 

Any idea how fast the different hammers hit? I haven't found any velocities listed only bps/bpm which doesn't tell how much "snap" the hammer does.

I can hit at about 1bps with my 6lb(for a limited time) and would be happy with a hammer that could hit that hard but at 2-4bps. 

I have access to an anyang 55, which is a sweet hammer, but it is way over kill for most of my work.  Bigger is better...till it goes through the slab ;), and I don't own my shop space so hammers that require a foundation or are overly noisy are out.

I have looked into treadle hammers but the ones I have seen are too slow, if I could get a treadle capable of hitting faster than my hand hammer that would be just the ticket, but hands are faster than legs usually (perhaps a pedal power one that struck with each leg?).

Thanks  again.

 

 

Ben Potter Bladesmith

 

 

It's not that I would trade my lot

Or any other man's,

Nor that I will be ashamed

Of my work torn hands-

 

For I have chosen the path I tread

Knowing it would be steep,

And I will take the joys thereof

And the consequences reap.

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I used to have a 40 pound mechanical powerhammer, It would hit about as hard as I can with a 5 pound hand hammer on a big anvil.

The advantage is that the hammer doesn't get tired and is also immune to carpal tunnel.:D

I really regret selling it with the damascus commissions I've been getting lately.

 

I had the same problem of not owning the shop space, and that hammer did fine on a rubber foundation bolted to the floor.

In my opinion a treadle hammer is useless for drawing out stock, it will make you just as tired as hand hammering.

 

 

 

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8 hours ago, Ben Potter said:

Any idea how fast the different hammers hit? I haven't found any velocities listed only bps/bpm which doesn't tell how much "snap" the hammer does.

 

Anyang has their bpm listed, see https://www.anyangusa.net. for instance the small 34lbs does 250 (no I don't work for them ;) they're just the only ones I have experience with)

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if you dont own the space a 25-50lb little giant or similar can be set on lumber to protect the slab

 

i cant help you with noise as thats subjective but a smaller hammer will have less bounce to the room its in so you will knock over less stuff with a 25 than a 50 and so on

 

i think my 50lb little giant is rated abound 320bpm thats 5.34ps if my american school system math skills are up to par

 

i almost think you are focusing on the wrong specs wile trying to figure out what you need and i dont know how to help you in that regard

 

heres a spec sheet for little giant hammers i would look at the forging capacity to help with usefulness

 

https://www.littlegianthammer.com/uploads/docs/2018-Useful-Information.pdf

Brandon Sawisch bladesmith

 

eagles may soar but weasels don't get sucked in to jet engines

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I've recently been told to look into a hydraulic press when it comes to shop space.  Advantages, no foundation, portable, lots of power.  I've never used one before, but for smaller shops and hobbyist like me, its a better option.  Cost, they are much cheaper than hammers.  Not having to do any additional construction to your work space is a plus too. 

 

When it comes to power hammers, I think the stroke capacities are just as important as how fast it hits. I've used a shop built tire hammer which is fast! Can draw out materiel very well at 50lbs, but it's stroke capacity is so little getting tooling under it was tricky. With tooling, any hammer can up its capability to move metal. The trouble with mechanical hammers is size and a short stroke until you get really big.  Even a small hammer takes up a lot of space, and proper anchoring for an upright hammer.  Mechanical hammers also must be tuned as they are usually one speed with very little variety. pneumatic hammers like the big blu I like it, but with a separate air supply I turned more to a mechanical hammer when I had access to both.  They have a great stroke capacity, and can be set for a one solid hit. The down side is the compressors supplying them.  Self contained seems to be the best of both worlds, but your still dealing with size of the hammer, its cost and the cost of rebuilding some shop space.

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39 minutes ago, Daniel W said:

I've recently been told to look into a hydraulic press when it comes to shop space.  Advantages, no foundation, portable, lots of power...

One potential disadvantage to be aware of is that it moves metal differently than a power hammer.  Because the press operates with one big squish instead of a lot of blows, the surfaces of the piece cools in contact with the dies cool significantly and the forging is more in the middle of the billet than the outer surfaces. 

RIP Bear....be free!

 

as always

peace and love

billyO

 

 

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