“As an empirical guide, shear strengths of carbon steel fasteners may be assumed to be approximately 60 percent of their specified minimum tensile strengths. For example, an SAE grade 5 hex cap screw has a specified minimum tensile strength of 120,000 psi. Therefore, for design purposes, its shear strength could be reasonably assumed to be 70,000 psi.�I put 150 lbs of weight on my wheel for a flywheel effect, I did not yet have hooked up to the generator which was suppose to be my break, I let spin for about five minutes, in trying to stop it, the cogs jammed against the levers. 1/2 inch bolts twisted splitting the 2/4s. I was really wasn't ready to run it, when I broke it. I had made it in a tent off of my deck, I am currently making a hard cover roof, to rebuild it under. My patent attorney said I could not patent what Bessler did, so I'm making changes. In the Bessler tradition I feel I'm giving clues, that is why I'm on here
I find it rather hard to believe that your machine could come close to developing enough torque to shear a grade #2 1/2" bolt or cap screw. Secondly I do not recommend spruce for use in pivoting or fulcrum loaded stress. If you wish to use a light or commonly referred to soft would, fir, hemlock or white pine, would be my choice.
I also believe you have a very dimwitted patent attorney. Bessler never patented anything and no one knows what he had worthy of patenting.
Ralph