Pulley and Belt Display

This pulley and belt display is another in my series of mechanical displays.
See the files for assembly instructions.

The pulleys are intended to be lightly press-fit onto the shafts. You may need to adjust your print settings to achieve this. The pulleys also have a pocket to accommodate a 3 mm square nut or even a standard nut so that a grub screw or button head screw can be used to secure the pulley. I don’t use the screws in this display as the light press fit is sufficient.

The knobs should be pressed onto the shafts with about 1 mm gap between the knob and pulley.

The belt is printed from TPU. I used 85A but 95A should also work.

The stand has cutouts on the corners to help prevent warping. Glue stick and organic supports are recommended for this part. There is also a hole for attaching a 10 mm bolt and nut(s) as needed to ensure the display doesn’t tip forward.

The bearing holder needs printing supports. Organic supports are recommended for flat horizontal surfaces. I recommend NOT using supports for the screw holes. The smaller diameter holes are intended to be M3 tapped. 

The collars should be lightly press-fit to the pulley shafts.

The back plate should be printed with a higher number of top layers if using white PLA to prevent the internal fill pattern from showing thru. I used 8 top layers and 20% cubic infill.

Purchased parts:

• 5 mm Aluminum rod cut to 50 mm - 2 pcs
• 695 bearings (OD: 13 mm, ID: 5 mm, t: 4 mm) - 4 pcs
• 693 bearing (OD: 8 mm, ID: 3 mm, t: 4 mm) - 1 pc
• M3 x 25 screws - 4 pcs
• M3 x 18 screw - 1 pc
• 3 mm x 10 mm tapping screws - 8 pcs

Other key parameters:

• 0.20 mm layer height (0.30 mm recommended for stand to reduce printing time.)
• 3 perimeters
• Cubic infill at 20%
• Supports for bearing holder
• Filament: PLA or PETG