Precision grade JIS grade N9 (JIS B1702-1: 1998) JIS quality 5 (JIS B1702: 1976)
section of gear Normal plane
Gear teeth Standard complete depth
pressure angle 20°
Helix angle 45°
① When mating screw gears made of the same material they may cause abrasion and scoring. It is recommended to mate Screw Gears made up of different materials.
② The allowable torques shown in the table will be the calculated values based on the assumed usage conditions.
③ The backlash values shown in the table are the theoretical ideals for the backlash in the normal 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 create a group of screw gears. For parallel shaft applications,
mesh opposite hands (RH and LH) of helical gear sets.
⑤ If the bore diameter is usually significantly less than φ 4, then the bore tolerance class is certainly H8. If the bore diameter is certainly φ 5 or φ 6, and the hole length (total size) Aluminum-Bronze Screw Gears exceeds 3 times the diameter, then the class is also H8.