IC Engine Crankshaft

[e2cub]

Hi, Any comments on using a large bolt like a grade 8, AN or NAS to make a crankshaft for an engine like the Mills 1.3 using the bolt head for the crank end? Thanks, Larry

[Harold_V]

While I'm not familiar with the crank of which you speak, using a grade 8 bolt should serve you well, assuming you can get the crank out of the bolt without using heat. Considering the grade 8 is made from heat treatable material, you'll alter it's qualities if you heat it. If you must do so, I'd suggest you totally anneal it, so you don't create stresses from heating and quenching. If you have proper heat treat capabilities, even that wouldn't be a problem, assuming you could provide a proper draw after heating and quenching.

Good luck----why don't you let us know how it goes with the bolt?

Harold

[e2cub]

Harold, Thanks for the response. I would try to machine the bolt without anealing or heat treating. I have used grade 5 and AN bolts in projects, but never tried grade 8 bolts. Will see how it goes. The Mills 1.3 is a diesel model air plane engine. It is one of the projects in the first issue of Model Engine Builder magazine. A great magazine. Larry