I have almost completed my beam engine design thanks to a few ideas I have found on here (thanks)! I am in the last phase of completing my design; however, I am having trouble constraining my eccentric wheel so that it rotates and drives the piston appropriately. I believe there needs to be a ball joint between the eccentric wheel and the sheave, but it is not working. Is there any ideas, or can someone take a look at it? Thanks in advance!