I'd like to build a guided helve hammer- a.k.a. "Appalachian" hammer, and I have a few design questions. This will (if I actually build it) be "junkyard" construction. Weather or not I build it will depend on if my available materials will work.

First off is the anvil. I can get materials for a 150# anvil, with almost all of it situated directly under my bottom die. If I understand powerhammer theory correctly, this restricts me to a 15# hammer?

Next is the spring. How thick/stiff do I want the spring, assuming I use a 15# hammer? How long?

In keeping with "junkyard" construction methods, it will be powered by a 1.5 HP Rockwell motor. I'm pretty sure its way overkill, but its the only one that the price was right on - free. The big kicker is that its a 3500 RPM motor. I think that's too fast? How many BPM do I want out of a small powerhammer? If I use a 1.5" drive wheel on the motor, and a small truck tire for the clutch (aprox. 26" diameter) that should put max speed around 200 BPM- if I did my math right. Does that sound right (both the math and the end speed)? What HP and speed would be ideal for a hammer this size?

Final and biggest question- How useful would a 15# hammer be? I want to try more damascus patterns and forge down some 2" stock, but with hand hammers its going to take a looong time. Drawing down from large stock, or drawing out a 1.5" billet for re-folding is taking too much time and energy.

 

Thanks for your time Gents!

Keenan

I get 202 BPM that's a nice speed especially for a light hammer. If you give it a reasonably deep throat it's going to be excellent for working on sheet or light plate stock.

It's pretty light for 2" stock but not out of reason it'll just take longer. You might want to set welds with ah and hammer though.

Frosty The Lucky.

15 # hammer could be very useful but BPM is more critical to achieve the most energy possible.

I would lean towards 300-325.  BPM

My 75# hammer is setup to make 212 BPM.

Smaller hammers should go faster.

In the formula to determine force one can see why speed matters so much in smaller hammers;

Force equals velocity squared times mass.

On 10/24/2016 at 5:36 AM, arftist said:

15 # hammer could be very useful but BPM is more critical to achieve the most energy possible.

I would lean towards 300-325.  BPM

My 75# hammer is setup to make 212 BPM.

Smaller hammers should go faster.

In the formula to determine force one can see why speed matters so much in smaller hammers;

Force equals velocity squared times mass.

Since my motor is a 3,500 RPM, faster speeds will be easier to design. 300+ BPM seems incredibly fast, I guess this just reinforces the need for good guards.

Any recommendation for the depth of stroke? I'm thinking 4-5", does that sound about right?

3.5 "crank offset for seven inches of stroke but allow. for whip

Ok, that's quite a bit more than I had anticipated. Thanks for the info!

I've collected most of the needed parts, and will be starting the build in a couple of weeks.