[rotorwrench]

There is a certain amount of artistic work in restoring a sphere to it's original shape. A gauge, whether a radius type of gauge or a hole size gauge, is only an aid to a restoration but it is a quick way to check progress. Fortunately, the wear pattern is somewhat predictable due to the design of the socket that the ball rides in. This leaves some of the original shape with which to work from. I have seen some that were in rough service so long without any repair, other than cupped washers, that the ball looks more like a prune than a sphere.

I start with restoring the surfaces that are closest to being the original size & shape to keep some form of accuracy for centering. The replacement ball ends are for those that are too far gone to restore. I use a hand held belt sander with course abrasive to rough them out and do the rest with finer abrasives. My gauge is round but has a cut out on the bottom to fit the attachment stub. This also helps for centering checks. My gauge was made using a wish bone that had almost no wear on it.