Precision grade JIS quality N9 (JIS B1702-1: 1998) JIS grade 5 (JIS B1702: 1976)
portion of gear Normal plane
Gear teeth Standard full depth
pressure angle 20°
Helix angle 45°
① When mating screw gears manufactured from the same materials they may trigger abrasion and scoring. It is suggested to mate Screw Gears made up of different materials.
② The allowable torques demonstrated in the table are the calculated values according to the assumed usage conditions.
③ The backlash values demonstrated in the table are the theoretical ideals for the backlash in the standard direction of a set ofidentical gears in mesh.
④ For offset shaft applications, match a RH with a RH, or LH with a LH, to make a set of screw gears. For parallel shaft applications,
mesh reverse hands (RH and LH) of Aluminum-Bronze Screw Gears helical equipment sets.
⑤ If the bore diameter is definitely less than φ 4, then the bore tolerance class is H8. If the bore diameter is φ 5 or φ 6, and the hole length (total size) exceeds three times the diameter, then the class is also H8.