The International Cessna^® 170 Association

I know we have some very intelligent folks here, and I have a question that I hope someone can help with. I haven't researched this anywhere else yet cause I felt certain I could get an answer here, or at least some direction where to start.
What is the formula for calculating the compression force between 2 objects that are bolted together? Example; propeller to crank flange, six half inch diameter bolts torqued to 45 ft/lbs. What would be the compression force in psi? I know thread pitch (so lets use a standard AN8 bolt, 20 threads per inch) and friction of the threads (depending on type of nut; self locking or not) and rotational friction during torquing would factor in. Any help would be much appreciated.

This calculator will give you an estimation of the clamping force of each
bolt. http://www.engineersedge.com/calculator ... e_calc.htm
Multiply the value calculated by 6, divide by prop hub contact area, should get you a ballpark figure in psi.

The calculator assumes a lot. On the page, click on "Torque Design" near the top of the page for more information.

Thanks, I'll check it out