HELICAL GEAR FORMULAS

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HELICAL GEAR FORMULAS. . .
NO
TO FIND
HAVING
RULE
1
Transverse Diametral Pitch
Number of Teeth and Pitch Diameter
Divide the Number of Teeth by the Pitch Diameter
2
Transverse Diametral Pitch
Normal D.P. and Helix Angle
Multiply the Normal D.P. by the cosine of the Helix Angle
3
Number of Teeth and Transverse D.P.
Divide the Number of Teeth by the Transverse D.P.
4
Normal Diametral Pitch
Transverse D.P. and Helix Angle
Divide the Transverse D.P. by the cosine of the Helix Angle
5
Helix Angle
Transverse D.P. and Normal D.P.
Divide the Transverse D.P. by the Normal D.P. — Quotient is the cosine of the Helix Angle
6
Transverse Pressure Angle
Normal P.A. and Helix Angle
Divide the tangent of the Normal P .A. by the cosine of the Helix Angle. Quotient is tangent of Transverse P.A.
7
Normal Circular Tooth Thickness
Normal Diametral Pitch
Divide 1.5708 by the Normal Diametral Pitch
8
Addendum
Normal Diametral Pitch
Divide 1 by the Normal Diametral Pitch
9
Addendum and Pitch Diameter
Add 2 Addendums to the Pitch Diameter
10A
Whole Depth (Coarser than 20 D.P.)
Normal Diametral Pitch
Divide 2.250 by the Normal Diametral Pitch
10B
Whole Depth (20 D.P. and Finer)
Normal Diametral Pitch
Divide 2.200 by the Normal D.P. and add .002
11
Addendum and Whole Depth
Subtract 2 Addendums from the Whole Depth