> 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/drive-rail-assembly.md). # Drive Rail Assembly ### Drive Rail Parts Required | **PART NUMBER** | **DESCRIPTION** | **QTY.** | | -------------------------------------------------------------------------------------------------- | ----------------------------- | -------- | | [REV-41-1762](https://www.revrobotics.com/rev-41-1762/) | 45MM X 15MM C CHANNEL - 408MM | 2 | | [REV-41-1687](https://www.revrobotics.com/rev-41-1687/) | U CHANNEL ENDCAP | 2 | | [REV-41-1492](https://www.revrobotics.com/rev-41-1492/) | M3 STANDOFF - 40MM | 2 | | [REV-41-1702](https://www.revrobotics.com/rev-41-1702/) | TENSIONING BUSHING - 39MM | 2 | | [REV-41-1359](https://www.revrobotics.com/rev-41-1359/) | M3 X 8MM HEX CAP SCREWS | 24 | | [REV-41-1361](https://www.revrobotics.com/rev-41-1361/) | M3 NYLOC NUTS | 8 | | | **ASSEMBILIES** | | | [ASSEMBLY 1](/duo-build/ftc-starter-kit-mecanum-drivetrain/90mm-single-sprocket-shaft-assembly.md) | 90MM SINGLE SPROCKET ASSEMBLY | 1 | | [ASSEMBLY 2](/duo-build/ftc-starter-kit-mecanum-drivetrain/75mm-single-sprocket-shaft-assembly.md) | 75MM SINGLE SPROCKET ASSEMBLY | 1 | | [ASSEMBLY 4](/duo-build/ftc-starter-kit-mecanum-drivetrain/drive-shaft-assembly.md) | DRIVE SHAFT ASSEMBLY | 1 | | [ASSEMBLY 5](/duo-build/ftc-starter-kit-mecanum-drivetrain/ultraplanetary-gearbox-assembly.md) | ULTRAPLANETARY ASSEMBLY | 2 | | [ASSEMBLY 6](/duo-build/ftc-starter-kit-mecanum-drivetrain/making-the-chain-links.md) | 56 LINK #25 CHAIN LOOP\* | 1 | ### Drive Rail Assembly Steps | | | | ------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | |

Attach an UltraPlanetary Assembly to a 45mm x 15mm C Channel - 408mm. Place M3 Screws and M3 Lock Nuts in the correct locations. Tighten until nuts are snug.

Note: The Output Cartridge of the UltraPlanetary Gearbox lines up with the fourth large (9mm) hole from the end of the C Channel.

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Place M3 Screws and M3 Lock Nuts in the correct locations. Tighten until nuts are snug.

Note: The Output Cartridge of the UltraPlanetary Gearbox lines up with the thirteenth large (9mm) hole from the end of the Channel.

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| Attach a U Channel End Cap to the Motor end of the C Channel. Add three Hex Cap Screws to hold it in place. Tighten the Hex Cap Screws. | |

| Attach a U Channel End Cap to the other end of the C Channel. Add three Hex Cap Screws to hold it in place. Tighten the Hex Cap Screws. | |

| Align the Hex of the shaft with the UltraPlanetary Gearbox. Insert the Drive Shaft Assembly into the UltraPlanetary Female Hex output. | |

| Remove the Shaft Collar, Mecanum Wheel, one 3mm Spacer, and the Through Bore Bearing – Long from the Drive Shaft Assembly. | |

| Remove the Shaft Collar from the 75mm Single Sprocket Assembly. Set aside for use later. | |

| Align the Hex of the shaft with the UltraPlanetary Gearbox. Insert the 75mm Single Sprocket Assembly into the UltraPlanetary Female Hex output as shown. | |

| Remove the Shaft Collar from the 90mm Single Sprocket Assembly. Set aside for use later. | |

| Insert the 90mm Single Sprocket Assembly, sprocket side toward the motor, into the fourth large hole from the non-Motor End Cap. | |

| Add a Shaft Collar to the end of the shaft. Tighten down the set screw. | |

Add two M3 Standoffs - 40MM along the C Channel for chain tension with M3 Hex Cap Screws. Add Tension Bushings onto each Standoff

Note: See the next step for locations.

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Tighten down the Hex Cap screws once the Standoffs are in the correct locations towards the bottom of the slotted holes.

Note: Screws should be tightened just enough to hold the standoffs in place. Chain tension is adjusted later in the drive rail construction.

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Add the 56 Link Chain Loop to the Sprockets.

Note: Keeping the Standoffs with Tensioning Bushings loose can help to get the chain loops on the Drive Rails.

If using the Mecanum Drivetrain Kit replace the chain link with the 120 Tooth Belt (REV-41-1800).

| |

Take a 45mm X 15mm C Channel – 408mm and seat the large holes on the bearings on each shaft.

Note: Make sure the bearings are square and the Channel End Cap holes line up.

| |

| Take eight Hex Cap Screws and secure the 45mm X 15mm C Channel – 408mm to the rest of the assembly. Screw into the End Caps and the Standoffs to keep the chain tensioned. | |

DRIVE RAIL ASSEMBLY COMPLETE

Repeat this step until you have two Drive Rail Assemblies.