Notice:Option (edge finder) for the whole set How to distinguish the three wires?The red wire is VCC, the black wire is GND, and the white wire is IO. Why is the concentricity different every time the probe is installed?Because your chuck spring clip cannot 100% uprightness. Every time the probe is installed, even if the concentricity is adjusted to 1 wire, there still be deviations when the probe is removed and installed again. So your chuck is AAA and above accuracy (concentricity less than equal 0.005), because many chucks in China have false standards, it is recommended to use a high- gauge or steel rod to check the table after installing the chuck. Look at concentricity. It's best to place the dial indicator at a distance of 50mm from the chuck, which is roughly the distance between the ball head of our probe and the root of the tool handle. Why am I obviously an AAA chuck, and the concentricity is still poor?That's because you bought a virtual label chuck.Under normal circumstances, if the spindle jumps by 0.01, the AAA chuck clamps the milling cutter and the table tool holder, the error may not exceed 0.02, and the error may not exceed 0.03 at most. There be a slight angular deviation between the center of the collet chuck and the center of the spindle, which be magnified by the length of your tool holder.Usually you use a calibration meter to measure the root of a milling cutter, and you can't see a big error, but because the stylus of the probe is about 50mm away from the tool holder, the error be further magnified. Therefore, be sure to choose high- chucks, which is more than a price difference of tens of . Type:NO Colour:As Shown Material:Metal Package Contents: 1 * edge finder Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.