[TheForge] drop hammer

[Bruce Freeman]

What with all the discussion about cheap power hammer, what about a drop hammer.  Okay, traditionally these were run from a water wheel, but the were later motorized with steam engines, no doubt.  

What I'm envisionaing is a classic drop hammer, heavy head on an oak beam, pivoted on the far end  - low tech.  Then come up with an appropriate modern "lifter".   One problem with traditional cam-type lifters was the friction on the cam.  Maybe a modified cam using a steel wheel rolling on the bottom of the beam would work.

Rough calculations suggest this is quite feasible.  Assume a 3' beam with a 100# head, and a double-wheeled cam (lifter) halfway along the shaft (none of which details matter).  Now assume a 4" cam "stroke" leading to an 8" hammer motion (based upon foregoing proportions).  Neglecting friction (!) I calculate this hammer could be run at ~150 blows per minute with one-half horsepower.  Now electric motors of 1 HP are commonly available cheap, and gas motors of a few HP are junked all the time.  Electric motors run either ~1700 or ~3400 RPM, meaning a 10:1 or 20:1 speed reduction would be needed, and this could be accomplished with a gearbox, belts and pulleys or sprockets and chains with not too much trouble.

So there you go.  A "novel" concept in a junk-yard hammer.

Bruce
NJ