On the Correct Meshing Conditions of Worm Gear and Worm

Check the backlash and top clearance and contact spot, the backlash and top clearance can be measured by plug ruler or lead-pressing method. The contact spot is pasted on the gear surface with red powder and oil, and then rotated to check its trace, which can judge the contact condition of the tooth surface. Different gears require different contact area (percentage).