How To: Gears
|Basic Properties||4140 Steel (Annealed)||7075-T6 Aluminum||6061-T6 Aluminum|
|Density||0.283 lb/in³||0.102 lb/in³||0.0975 lb/in³|
|Tensile Strength (Ultimate)||95 KSI||76 KSI||45 KSI|
|Tensile Strength (Yield)||60.5 KSI||67 KSI||40 KSI|
|Weight Compensation||1.000 lbs||0.358 lbs||0.310 lbs|
Sources: McMaster Carr & MatWeb
WCP uses 7076-T6 to provide lighter gears than steel (~1/3 lighter), while still being stronger than 6061-T6 Aluminum.
General Gear Information
- Gears are normally 0.500" wide (Unless otherwise specified)
- Gears have a protrusion, a tiny nub on both sided of the gear (Unless otherwise specified)
- Gears will come anodized (Type III), used to harden the gear and prevent corrosion
- Gears will have teflon coating on them
Note: DO NOT RUN GEARS WITHOUT PROPER LUBRICATION
- The nub is designed to butt up against the face of a bearing, this eliminated the need for a spacer and reduces part count
- WCP highly suggests using DuPount (Dry-Grease) for lubrication. McMaster #8710T35
- The normal recommended rule of thumb for FRC robots is +.003 spacing between gears
- These gears have a modified tooth profile to compensate for anodizing.
For a single stage gearbox (custom): +.000 - +.001 backlash
For any other gearboxes: +.002 - +.003 is recommended.