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 manufactured from the same material they may trigger abrasion and scoring. It is suggested to mate Screw Gears composed of different materials.
② The allowable torques proven in the table will be the calculated values based on the assumed usage conditions.
③ The backlash values demonstrated in the table are the Aluminum-Bronze Screw Gears theoretical values for the backlash in the standard direction of a pair ofidentical gears in mesh.
④ For offset shaft applications, match a RH with a RH, or LH with a LH, to make a group of screw gears. For parallel shaft applications,
mesh opposite hands (RH and LH) of helical equipment sets.
⑤ If the bore diameter is usually less than φ 4, then your bore tolerance class can be H8. If the bore diameter is definitely φ 5 or φ 6, and the hole length (total size) exceeds three times the diameter, then your class is also H8.