Facts: I picked up a used trav-a-dial for my lathe. It came will all instructions so I know about the curvature on the wheel for calibrating it, the 'springy' mounting block and the springs are in good shape. I made a decently stout mount and went through the whole procedure for aligning it including making sure it's parallel to the direction of travel, I only got to about .0005 (half a thou) but sheesh.... Using my Chineese made 2 inch dial indicator the closest I can get it is -0.008 over 2 inchs.. that's 8 thou short on a 2 inch travel. To get this it's angled at about 20 deg. If I set it level it's -0.010 (10 thou) short on the 2 inch travel. FWIW I would have figured that tilting it would have made the error GREATER since it's effectivly making the wheel smaller. These numbers are ROCK solid, (well as rock solid as I wanna test) meaning I whipped the carrige back and forth for 5 minutes and it dialed in EXACTLY to0 so it's no loosing or gainig anything.
Questions: Is this as good as they get? Is this about the ammount of difference you'd expect from level to 20 deg tilt (2 thou)? And yes for what I do -10 thou over 2 inchs is acceptable and that's where I'll leave it, easier to remember 5 thou in 1 inch to compensate( if I EVER need that much accuracy).