Spur-wheel.
The ordinary form of cog-wheel.
The cogs are radial and peripheral, and are adapted to engage counterpart cogs on another wheel.
See list under gearing.
The pitch-lines of the
driving and the
driven wheel are in one plane.
 |
|
Spur-gearing. |
Proportions of wheels.
Spur and bevel gear:—
| Height of tooth | = 12/15ths of pitch. |
| Height below pitch line | = 1 3/30ths of pitch. |
| Height above pitch line | = 1 1/30ths of pitch. |
| Thickness of tooth | = 1 9/40ths of pitch. |
| Breadth of wheel | = 2 1/2 times the pitch. |
| Edge of rim | = space. |
| Feather under rim | = space. |
| Thickness of feathers | = thickness of tooth. |
| Breadth of arms | = pitch × 2. |
| Thickness round eye | = pitch. |
| Feather round boss | = length of tooth. |
