Specifications
Precision grade JIS quality N9 (JIS B1702-1: 1998) JIS grade 5 (JIS B1702: 1976)
Reference
section of gear Normal plane
Gear teeth Standard complete depth
Normal
pressure angle 20°
Helix angle 45°
Material CAC702
① When mating screw gears made of the same material they may trigger abrasion and scoring. It is recommended to mate Screw Gears composed of different materials.
② The allowable torques Aluminum-Bronze Screw Gears demonstrated in the table are the calculated values based on the assumed usage 
conditions.
③ The backlash values demonstrated in the table are the theoretical ideals for the backlash in the normal 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 create a group of screw gears. For parallel shaft applications,
mesh opposing hands (RH and LH) of helical gear sets.
⑤ If the bore diameter can be less than φ 4, then your bore tolerance class is certainly 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 can be H8.