I spent $130 on one of those fancy 3D edge finder sets everyone raves about. Took it out of the box, set it up on my Bridgeport, and it gave me readings all over the place. Calibrated it three times, still off by about 0.004. My old $15 wiggle style finder has never missed once in 8 years. I get the appeal of digital, but for manual setups it just added more variables. Anybody else have better luck with the cheap mechanical ones, or did I just get a bad unit?