Quote Originally Posted by mklotz View Post
Re: "bumping the tip over the edges of table slots and blocks or something" ...Get a brake rotor and lay it on the (clean) table; swing DI on that.
Yup, or a bearing race. Or better yet, make a spindle square, because sometimes the other stuff doesn't fit on top of whatever one is trying to indicate .


The spindle square shaft doesn't need to be precisely aligned with the frame, nor do the indicators precisely spaced from the center. It can be off like 0.1 inch on a 5 inch spindle square and it wont matter (the error created by this decreases the more you get in tram). Home shop tolerances are more than good enough to make a functional tool. Think about it as hooking two indicator tramming bars to the mill at the same time. The position of the bars and the indicators is irrelevant, i. e. one can be above the other or they can be facing different directions. The only things that matter are that their tips are 180 degrees apart, that you can reach roughly the same spot on the table to zero both of them. We can even have some indicator cosine errors, as long as they're roughly the same, as we only compare the produced measurement without really caring for the actual linear displacement.

And no, I didn't mention any of that in the video , but I do realize that explaining some things in more detail is necessary.