Review on Micrometer Internal Diameter Accurate Calibration by Mark Toth

Definitely not what is pictured or described. Plastic housing, the marking on the device does not match the picture. The build quality is not up to par. When I got it it was very tough. Simply by using the ratchet it will not rotate without the ratchet engaging. Couldn't even tell if it was calibrated to the included 5mm ring. Decided to do whatever it takes to take it apart and try to get it working. It was found that the cam alignment moving pin/blade was too tight, the adjustment slot screw was damaged at the factory. Removing the differential barrel was EXTREMELY difficult, it really got stuck at the factory. The slot for the barrel locking screw is also damaged. The screw collar of the differential was tightened to the stop. There was debris on all threads of the differential screw. After a complete disassembly, cleaning and reassembly I was able to get everything going smoothly. But the moving jaw wobbles because when I tighten the leveling blade to take out the wobbling jaw, it doesn't rotate smoothly. I check the lapping of the pins, they are not parallel (they have a taper). When I check the accuracy afterwards, the best I can get is that it's ALWAYS 0.04-0.05mm larger (trying to account for the pin taper). Should not be returned. I'll use them along with a good micrometer. Open them up in the hole, tighten the set screw (which should also loosen) and then measure the pins with an outside micrometer.