> For the complete documentation index, see [llms.txt](https://docs.revrobotics.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.revrobotics.com/duo-build/ftc-starter-kit-mecanum-drivetrain/90mm-single-sprocket-shaft-assembly.md).
# 90mm Single Sprocket Shaft Assembly
### Single Sprocket Shaft Assembly Parts Required
| **PART NUMBER** | **DESCRIPTION** | **QTY.** |
| ------------------------------------------------------- | ---------------------------- | -------- |
| [REV-41-1323](https://www.revrobotics.com/rev-41-1323/) | 15MM SPACER | 1 |
| [REV-41-1324](https://www.revrobotics.com/rev-41-1324/) | 3MM SPACER | 2 |
| [REV-41-1326](https://www.revrobotics.com/rev-41-1326/) | THROUGH BORE BEARING - SHORT | 2 |
| [REV-41-1327](https://www.revrobotics.com/rev-41-1327/) | SHAFT COLLAR | 1 |
| [REV-41-1338](https://www.revrobotics.com/rev-41-1338/) | 10 TOOTH #25 SPROCKET\* | 1 |
| [REV-41-1348](https://www.revrobotics.com/rev-41-1348/) | 5MM X 90MM HEX SHAFT | 1 |
### Single Sprocket Shaft Assembly Steps
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| ------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
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](#single-sprocket-shaft-assembly-steps) | Add a Shaft Collar flush to the end of the 5mm x 90mm Hex Shaft.
Tighten the Shaft Collar.
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| Slide a Through Bore Bearing – Short onto the shaft.
Note: the smaller portion of the bearing faces towards the Shaft Collar.
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| Slide a 3mm Spacer onto the shaft.
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| Slide a 10 Tooth # 25 Sprocket onto the shaft.
Note: For the Mecanum Drivetrain Kit, replace the sprocket with a 24 Tooth Pulley
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| Slide a 15mm Spacer onto the shaft. |
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| Slide a 3mm Spacer onto the shaft. |
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| Slide a Through Bore Bearing – Short onto the shaft.
Note: the smaller portion of the bearing faces away from the Shaft Collar.
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| SINGLE SPROCKET ASSEMBLY COMPLETE
Repeat the above steps until there are two completed Single Sprocket Assemblies. Set aside for later.
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