for helical gear the helix angle generally ranges from
Helix angle In helical and worm gears, the helix angle denotes the standard pitch circle unless otherwise specified.[1] Application of the helix angle typically employs a magnitude ranging from 15° to 30° for helical gears, with 45° capping the safe operation limit. The angle itself may be cut with either a right-hand or left-hand orientation.[5] In its typical parallel arrangement, meshing helical gears requires that the helix angles are of the same magnitude and cut oppositely .