Pulley
These pulleys are attached directly to NEMA 17 stepper motor shafts or onto the driveshaft. They transfer power from the motor to the belt such that FarmBot can move in the X and Y directions.
Specs
| material | Aluminum |
| number of teeth | 20 |
| inner diameter | 5mm |
| outer diameter | 15mm |
| height | 14mm |
| setscrews | M4 x 0.7 threads, 3.75mm length |
| setscrew quantity | 2 |
| setscrew material | Stainless steel |
| setscrew drive size | 2mm hex |
| max belt width | 7mm |
| pitch | GT2 (2mm) |
| Price | $6.00 |
| Quantity |
Express - 3
Express XL - 3 |
| Purchase | The FarmBot Shop |
| internal part name | GT2 Pulley - 20 Tooth |
| cost | $0.85 |
Component tests
| Test | Description | Target | Tolerance |
|---|---|---|---|
| Number of teeth | Count the number of teeth on the pulley. | 20 | +/- 0 |
| Pitch | Mate the pulley with a belt and inspect tooth engagement | The pulley should fully engage the belt’s teeth at all points of contact. | N/A |
| Tooth width | Measure the width of the teeth using digital calipers. | 7mm | +/- 0.5mm |
| Overall length | Measure the overall length using digital calipers. | 14mm | +/- 0.5mm |
| Outer Diameter | Measure using digital calipers. | 15mm | +/- 0.5mm |
| Hole diameter | Measure the diameter of the motor shaft hole using digital calipers. | 5mm | + 0.05mm |
| Motor shaft fit | Assemble the pulley to a NEMA 17 motor shaft and tighten the setscrews. | Pulley should fit snug and concentrically. | N/A |
| Number of setscrews | Count the number of setscrews. | 2 | N/A |
| Setscrew drive size | Use a hex driver to validate the drive size of the setscrews. | 2mm | N/A |
| Material | Ensure the material is aluminum and stainless steel and will not rust by holding a magnet to the part. | Aluminum and stainless steel (no magnetic attraction) | Weak attraction to stainless steel is permissible. |