How I measure piston-rod end play

I was deleting old files from a thumb drive and found these pics that show how I measure the amount of play in pistons.  I'm not good measuring by just holding the piston/rod in one hand and a caliper in the other, so I made a simple jig to do it.

I took a scrap piece of ply and cut it into two pieces for the jig.  The first is just a stick with a couple more pieces glued to the bottom so I can clamp it in a vise, and a second piece for an arm with a slot in it.  I hammered a brad into the vise piece and hook the bottom of the rod on it.  Then I use the arm to hold the piston out to max distance and use my caliper to measure the distance.  Then I use the caliper and measure the minimum length.  The difference in the two measurements is the total end play in the ball joint.










The Simple Mark