I bought these. I haven't purchased the shaft or other bearings yet. I'm putting three of the rod ends on a three sisters style engine. However, I'm using regular off-the-shelf pneumatic cylinders instead of custom-made cylinders.
I'm using the 10mm bore hole because the cylinders I bought have 10mm threads on their ends.
These are the rod ends for my pneumatic cylinder rod ends. They have an M10 thread and a 10mm hole.
I would press two of these bearings into the crank wheel, and press a pin into them. Alternatively, I could just press the crank pin into the crank wheel directly, but I'd still rather not have the rod end bearings slide along the crank pin axis.
I wanted an interference fit so as to not need to use a nut and bolt.
I'm building a radial engine; a variant of the three sisters design found here. This page here has a variety of small compressed air/steam engine designs and plans.
The roller bearing is going to be pressed into the crank wheel. The pin is going to connect the 3 pneumatic cylinders. So, I don't want the pin to wobble inside the bearing. And I want the pin to be perpendicular to the crank wheel.
I suppose I could press a pin directly into the crank wheel. Then the only bearings I'd be using are the rod ends on each piston rod. If I press the crank pin into the crank wheel, I still need to connect the rod ends onto the crank pin in such a way that they don't move themselves off the pin.