Chapter II: =THE TEETH OF GEAR-WHEELS (Continued).=

=Worm and Worm-Wheel=, or wheel and tangent screw 28 to 31
General description of 28
Qualifications of 28
The wear of 28
=Worm-Wheel Teeth=, the sliding motion of 28
When straight have contact on the centres only of the tooth
sides 28
That envelop a part of the worm circumference 28
The location of the pitch line of the worm 28
The proper number of teeth in the worm-wheel 29
Locating the pitch line of the worm so as to insure durability 29
Rule for finding the best location for the pitch line of the
worm 29
Increasing the face of the worm to obtain a smoother action 29
=Worms=, to work with a square thread 29
=Worm-Wheels=, applications of 30
=Gear-Wheels= with involute teeth 31 to 34
=Gear Teeth.= Generating the involute curve 31
Templates for marking the involute curve 32
=Involute Teeth=, the advantages of 34
=Gear Teeth=, Pratt and Whitney's machine for cutting
templates for 35