What Size Hammer??

[Jason @ MacTalis Ironworks]

Actually guys, there is ALOT of medical evidence indicating that larger hammers tend to prevent RSI than cause it as they force you to slow down. However as Brian, Alec, and others will repeat time and time again, there is a technique to using big hammers as we do. If you try to use a big hammer like you would use a little one, Heck yeah! You WILL tear yourself up. With a larger hammer it isn't so much swinging, as lifting and letting drop. We tend to choke way up on the hammer unless we need some serious whackage, like for setting shoulders. If I or Brian, or Alec tried to swing our monster hammers like alot of guys swing their 2's, we probably wouldn't be able to get through an hour of forging. Technique, technique, technique.

[Ramsberg]

The production of damage to ones self is directly related to the leverage on the wrist created by the hammer.

Looking at Alecs videos the center of his hand looks to be roughly 4" from the center of the hammer head. The head is 5 lbs, multiply that by 4" and we get 20 inch pounds of force.

Compare that to a guy using a 2 lbs hammer with the center of his hand 12" away from the center of the hammer head, that is 24 inch pounds of force. A 3 lbs head at 12" is 36 inch pounds, that is 1.8 times the leverage created by a short grip with the 5 lb hammer.

Grab a 6 lb hammer by the head, swing it and notice that there is virtually no stress in your wrist, forearm or elbow.

Caleb Ramsby

[Ramsberg]

Maybe we could all learn a bit by sharing the head weight and distance from the center of hammer head to center of the hand.

My favorite hammer is 3 lbs and I hold it 8 1/2" from the head, that gives 25 1/2" lbs of force.

Caleb Ramsby

[pkrankow]

My point earlier is to try and see, different hammers for different tasks. Yes, I did get a 4# hammer recently, as it was the biggest I could get...and promptly rehandled it, but that is because of a bad handle from the start I didn't notice till I had the face dressed.

Ramsberg has a point, but the frame of reference should be how the wrist is resisting in lifting and not the force applied to the work, there is a whole lot more system that needs included for that (elbow, shoulder, height of total lift/drop, and more). I find it interesting that with a big hammer choked up the wrist is working less than with a small hammer held back on the handle. I will think about that next time I am hammering.

Phil

[Alec.S]

Nicely put, ramsby!!!!!!!!! :)

[Ramsberg]

I looked it up and it appears that the record for a sledgehammer lift is held by Slim the Hammer Man with a pair of 56 lb sledges on 31" shafts, that would give 1,736 lbs of force or resistance to the wrists!

Phil, I should have been more specific, I was refering only to the static load or force on the wrist when lifting the hammer dead off of the anvil. Yes, much more must be considered when figuring out the striking force on the work.

One thing of interest is that the old steam hammer makers found that although a smaller hammer moving fast would produce the same foot pounds of force as a heavier one moving slowly, there was a difference as to what part of the work was being deformed. The lighter hammer would deform the outer surface of large stock and could cause internal sheering of the metal. The heavier hammer would penetrate deeper into the work and deform it all the way through. This is why I prefer a light hammer of 1 lb or so to finish or smooth thin elements, it just kisses the surface of the metal.

Caleb Ramsby

[Borntoolate]

Interesting that when I got into forging I actually was having a bit of tendinitus in my hammer arm. This was pre-existing and not caused by blacksmithing. I worked through that and it has healed. Since the tendinitus cleared up I have been using the larger hammer and recently moved to 4#. I have no issues with tendinitus or pain whatsoever. I am now having some tendinitus in my other arm. Maybe I need to start hammering with it!