From left to right; the first two one piece crankshafts (.375X.500) made of 8620 tool steel had their .281 dia crank pins sheared off during dyno runs. The next three crankshafts (.375X.500) made of 9310 tool steel through hardened failed when their .3125 dia crank pins were pressed in with a heavy press fit (.0013). The last two crankshafts (.3937X.5906) made of AISI S-7 tool steel through hardened, with .3281 dia crank pins at .0013 to.0015 press fit, have never failed on any dyno run or lake testing.
