b
d
h
a
h
f
d
a
d
f
d
b
a
h
p
Round holeKeyway Flattened round hole N-edge
d
l
d
l
b = Face width d = Pitch diameter d
a
= Tip diameter d
b
= Base diameter d
f
= Root diameter h
a
= Addendum h
f
= Dedendum
β
= Helix angle p= Pitch a
d
= Ledge diameter a
h
= Ledge height d
l
= Axle hole diameter b
p
= Keyway width t
p
= Keyway depth t
a
= Flattening depth
t
a
b
p
t
p
a
d
β