Frankenhammer- hammer design

[JohnGrafft]

In the workshop for metal demolition my foreman has modified a *3.5 pound* (estimate) cross peen hammer by removing the fiber glass handle and replaced it with a 1 inch diameter steel cable. The only bought being it’s stiff enough to not lose accuracy. You can increase force with the potential energy that’s generated during the swing and the bunching of the cable. (With proper flicking technique at end of swing) also it dampens the impact to you arm. However I don’t know if this would reduce or increase low frequency vibrations. What are your thoughts?

 

[George N. M.]

John:  I would want to see some empirical data that a slightly flexible handle would increase the impact of the blow because I'm skeptical of that.  Even with some flex the hammer head would still be accelerated to a certain speed at impact which is dependent on how fast you arm is travelling.  Conservation of energy and all that.  It is possible that a slightly flexible handle might mitigate the impact shock on the hand and arm though.  That aspect is much more subjective to the user.

BTW, any calculation of force between the cable handled hammer and a rigid handed hammer would have to take into consideration the additional mass of the steel cable which will contribute to the impact.

It is also possible that a flexible handle would contribute to the duration of the impact before the elastic rebound properties of the hammer head and struck material overcame the inertia of the hammer and arm to bounce the hammer back.

Still, it is an interesting concept.

"By hammer and hand all arts do stand."

[Frosty]

You see lots of "good" ideas like that and I've yet to see a better hammer handle that wood or one of the new composites I have and use both axe and sledgehammers with the yellow plastic handles. Other than not having to worry about hitting a balk of wood I'm splitting with the handle I haven't noticed any significant difference. They DO feel different to the hand.

There are a number of issues with using cable: It's twisted and even non-rotating wire rope twists under stress. I'd expect that hammer to want to hit slightly out of plane with the anvil face. Being flexible, how are you going to control the angle front to back? Miniscule differences in your swing is likely to make it strike off plane, heal or toe.  Yada yada.

What difference does precise control make for a demolition hammer, so long as you can miss your body with it, while you're just busting stuff up, its good. No? I don't allow pipe handled hammers in my shop, even if they're a visiting smith's hammer.

Frosty The Lucky.

[anvil]

I agree with Frosty etc al. 

[Frosty]

 

[anvil]

[JHCC]

One thing that cable DOES make a good handle for is top tools for the power hammer. They're stiff enough to allow you to place them precisely, but if they get misaligned, they won't jerk or leap under load.

[JohnGrafft]

I appreciate the feedback! When I have more time I’ll definitely get some empirical data just to see. I do think Frosty that the twisting tends to mix up the aim. It’s wants to recoil slightly under the strain. I definitely don’t think it would be good for smithing but creating a hammer like this for demolition I was curious as to how it might be better or worse for your body. Thank you guys for all your input

[ThomasPowers]

Note that any handle you need to grip more tightly to use is bad for your hand/arm physically as it puts your tendons and ligaments in tension as any forces/vibrations go up the handle.  One reason we tell beginning smiths to modify their wooden handles if they are too large to grip comfortably without strain.

We see a lot of metal handled tools out here as the climate is hard on wood and if you use day labor they are hard on tools.  (My brother had a landscaping business and certain folks when given a job that was a lot of work would "accidentally break" the tools and then sit around collecting pay until they were repurchased or fixed again.  Short sighted as they tended to not be hired again...)

[rockstar.esq]

Adding to Frosty, I would suggest that a flexible handle will also tend to make repeated blows harder since it dampens the hammer's bounce, as it inevitably alters the bounce path.

Back when I was an apprentice, I knew a carpenter who was using a framing hammer made by Stanley that had a metal tuning fork design that was visible through whatever clear plastic stuff they made the handle out of.  He swore up and down that it was noticeably better.  At the time most rough framing carpenters went with a long handled and heavy (2 lbs) checker-face hammer.  

Recently, I was watching "Essential Craftsman" on youtube and he was talking about how his hammer choice evolved over time.  Currently, his favorite is a 15 Oz Titanium hammer with a tool steel face from a company called "Stiletto tools".

While it's tempting to obsess over kinetic energy calculations, I think that's looking at the wrong end of the handle in terms of work.  The human effort involved is mostly in the post blow recovery.  Any reaction forces that aren't in the direction you're lifting in will add work to the user. 

 

 

 

[JohnGrafft]

Good points from both of you. I didn’t think about the rebound. That would definitely dampen it. Time tested wood and newer composite materials work best is what I’m seeing. No need to reinvent the wheel haha

[George N. M.]

My late wife used to point out that if we didn't reinvent the wheel we'd be driving around with chunks of logs on our modern cars, sort of like the Flintstones.

"By hammer and hand all arts do stand."

[Irondragon Forge ClayWorks]

When we were building the house, I was using a steel shaft leather handle Estwing framing hammer. One day we were up on the roof laying the decking and I commented that my elbow and shoulder were bothering me. The old carpenter who was the foreman on the crew said "let me see your hammer". He then threw it as far as he could out into the woods. Then he went to his tool box and gave me a hickory handled framing hammer (don't remember the brand) and with in a couple of hours the pain was reduced and the next day it was gone. Sold me on wood handles right then & there. I still have that hammer 37 years later.

[anvil]

Lol, my thoughts exactly. I wouldn't have or use a metal handled hammer on a bet.

[ThomasPowers]

Well I have a steel handled rock hammer; but it's not used like a carpenter's or blacksmith's hammer---more prying in my experience and less pounding.

[Frosty]

I have Dad's Eastwing rock hammer and one of his wooden handled ones. As Thomas says, you don't use a rock hammer like a  "normal" hammer. You crack rocks or pry pieces loose. The prying breaking handles is why Dad bought the Eastwing. 

I like a little prybar for rock hounding, especially fossil hunting, a speed bar is good but not as tough, the edge chips or rolls easily.

Frosty The Lucky.

[anvil]

I should have said "in the shop". I do have a steel handled eastwing 32oz for the little carpentry work I do. It's great for pulling nails.