The AIO version shown in these pictures mounts the control board in the front with cables routing to the motor in the back, based on a concept by @thearmpit. The AIO Cover part used here is a custom design not covered under CC BY-NC-SA 4.0 license.
What is a capstan drive?
A capstan drive uses rope and a pulley to transmit motion. For an excellent explanation of the mechanism, watch this video by Aaed Musa:Capstan Drive Explained
Learn how capstan drives work and why they’re effective for high-torque applications.
Why choose capstan over belt?
The standard belt-driven OSSM can experience slipping at higher torques. While this may result from build errors, the capstan drive eliminates this issue entirely.Comparison to standard OSSM
- Advantages
- Disadvantages
- Same form factor as standard OSSM
- Equal or quieter operation
- Only 13cm effective rail length loss (450mm rail = 32cm stroke)
- 2.7x stronger (32kg vs 12kg capacity)
- Same maximum speed
- No belt slipping
- No custom PCBs required
- PitClamp compatible
- Compatible with all custom end effectors
Configuration options
AIO vs normal version
- AIO (Recommended)
- Normal
The AIO mod version mounts the control board in the front of the motor head with integrated cable routing. This is the recommended configuration.
Pulley versions
- Bushing Pulley (Recommended)
- 3D Printed Pulley
The bushing pulley is superior in every way:
- Better durability
- No deformation over time
- Supports rail lengths up to 450mm (500mm likely possible)
Supported rail lengths
| Pulley Type | Tested Length | Maximum Recommended |
|---|---|---|
| Bushing | 450mm | 500mm (untested) |
| 3D Printed | 400mm | 400mm |
Rope selection
Required rope: Liros DC pro 161 (or equivalent Dyneema DM20, SK99, SK75 with max 1mm diameter)Why rope selection matters
Why rope selection matters
The rope must have minimal stretch under load. Testing by community member @neos demonstrated that generic UHMWPE rope from AliExpress stretches excessively and breaks under load. The specified Dyneema rope maintains consistent tension for reliable operation.
Alternative rope specifications
Alternative rope specifications
If you cannot source Liros DC pro 161, look for:
- Material: Dyneema DM20, SK99, or SK75
- Maximum diameter: 1mm
- Verified low-stretch construction
Print settings
Pre-configured .3mf files are included for most parts with optimal settings.
| Setting | Value |
|---|---|
| Walls | 6 |
| Infill | 20% |
| Supports | Try without for AIO_cover (bridges only); enable if needed |
Bill of materials
| Part | Estimated Cost | Source |
|---|---|---|
| 60AIM40F Motor | ~110€ | Superbuy/Taobao |
| OSSM Control Board + Remote | $91 USD (excl. tax/shipping) | Research and Desire |
| MR115 Bearings (5x) | ~3€ | AliExpress |
| Hardware kit | ~30€ | See hardware/Hardware.txt |
| PLA Filament (1kg) | ~8€/kg | AliExpress |
| Liros DC pro 161 Rope (5m) | ~15€ | Kite Line Shop |
| Bushing 20x23x30mm | ~5€ | Agrolager |
| MGN12H Linear Rail + Wagon | ~10-15€ | AliExpress (450mm) |
| Epoxy Glue | ~3€ | AliExpress |
| 4-pin JST Header Cable | ~2€ | AliExpress |
| 2-pin AWG 18+ Wire (30cm) | ~2€ | AliExpress |
| Kinesio Tape | ~3€ | Local drug store |
| 36V 5+A Power Supply | ~68€ | Voelkner (PSU) + Adapter |
| Total | ~345€ |
Community support
Discord Thread
Join the discussion, share feedback, and get help with your Capstan OSSM XL build.
Special thanks to everyone who provided suggestions and helped overcome challenges during development!