I have an interesting scenario. I'm trying to determine the amount of force that is applied to the underside of a bottle cap (the force from the bottle neck pushing upwards) as the cap is torqued onto the bottle (assume a 16 oz plastic bottle of Coke for example). After contact from the bottle on the underside of the closure the torque required to move the cap (to close it tighter) rises quickly. I want to know if I torque the cap on a given amount, say 20 torque in-lbs, what is the resulting force or pressure that is applied to the underside of the cap at that torque level. I assume the surface area of the bottle neck that contacts the cap would be important. Anything else? How do you factor in the effect of friction between the threads on the cap and those on the bottle in the torque load? Any help would be awesome, thanks.