I'm rebuilding a couple hydraulic cylinders. In addition to the wrench flats on the clevis end of the rod, there is a 0.1 flat machined the entire length of the threads. At first, I thought that this was there so that the clevis clamp bolt could pass through when the flat is lined up with the bolt hole. But the bolt hole on this clevis doesn't intersect the rod threads.
I went ahead and put it on the rods since they were already in the vice but I don't know what it's for. So, what is that flat for?