1. Loosen the 2 screws that fix the differential head
2. Put it on the ordinary glass countertop (or 00-grade marble countertop, do not use tempered glass)
3. Adjust the two differential heads to 0, naturally vertical, and then use a flashlight (or mobile phone flash) to illuminate from the opposite side of the scraper to check that the bottom of the scraper does not leak light.
4. Tighten the 2 screws securing the micrometer head, and the calibration is complete.
Note: Since Shanghai Jiuran’s adjustable applicator does not use springs, calibration and disassembly for cleaning are more convenient than those using springs.