First, in your calculations you're mixing in and mm. The 6 and 5 mm bolts diameters should be converted into inches if you are going to use in-lbs torque in the calculations.

Clamp force:

5 mm (.1968") = 1,249 lbs

6 mm (.2362") = 951.98 lbs

Be aware that this is the clamp or axial tension force applied to the FASTENER. The actual force needs to be looked at in terms of psi on the parts related.

Also, the torque seems way high for the diameter of the screws.

See:

http://www.engineersedge.com/torque.htm

http://www.engineersedge.com/calcula...orque_calc.htm

and

AC+2000Paper517.pdf