Concerning homemade power hammers (rocking beam types), how does the lenght of the stroke relate to the weight of the shaft and head? For instance, on a 25 total weight hammer, would a stroke of 12 inches be about the norm? And for a 50 machine, how long a stroke would be proper..? I imagine it would be longer than a 25 pounder. May as well ask for the 75 and 100 pounders too.
Chas,
I don't think there is any relationship between head weight and length of stroke. The avaerage that I have heard of is in the 6-9 inch range. Typically, the homemade "helve" hammers are setup to be driven by an electric motor with an off center disc. The stroke length is the relationship between the distance from the center of the motor shaft to the center of the off-center rod along with the length from the pivot arm center to the rod connection AND the distance from the pivot arm center to the hammer head. All three of these distances can effect the stroke as well as the horsepower needed to drive the hammer. Now, once the hammer is assembled, there is some tweeking necessary to balance the system and keep it from walking around the shop. The biggest concern that I have read about is making the entire machine heavy enough to stay put.
If you run a Google search for "baby helve hammer", you should be able to find 2 JPG files that are hand-drawn sketches by Jr. Strasil that really does a good job of showing you how to build one.
Hope this helps,
I was thinking of the Little Rusty type hammer. A car spring on top of a column raising and dropping a hammer head on the end of a rectangular shaft.
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