Idler Assembly

Idler Pulley Parts

Get the parts ready to assemble the idler pulley. We'll use the following parts to assemble the idler pulley.

  • 5x M3 heat set inserts
  • 1x M4 slim t-nuts
  • 1x Ball Bearing (10x15x4mm)
  • 1x M4 x 8mm button head metric screws
  • 3x M3 x 6mm button head metric screws
  • 2x M3 x 8mm button head metric screws

Bearing Pulley

Fit the pulley wheel over the ball bearing. It should press fit with a tight tolerance. The groove on the wheel is designed to couple a rope or piece of string. Side Note: This idler pulley component was used in our New Year's Eve Ball Drop project.

Heat Set Parts

Install M3 heat set inserts into the pulley holder and coupler parts. Reference the photo for best placement.

Install Ball Bearing

Place the ball bearing over the peg in the center of the holder. Press it flush up against the post, it should have a tight fit.

Secure Ball Bearing Cover

Insert an M3 x 6mm screw through the ball bearing cover. Place the screw into the insert on the bearing holder. Fasten to tighten the screw. Check and make sure the wheel can spin freely.

Secure Holder to Mount

Place the coupler over the mount and line up the mounting holes. While holding the parts together, insert and fasten machines screws and tighten. Use two M3 x 6mm button head screws.

Secure Mount to Coupler

Place the mount over the coupler and line up the mounting holes. While holding the parts together, insert and fasten machines screws and tighten. Use two M3 x 8mm button head screws.

Install T-Nut 

The coupler will fit over the piece of 2020 aluminum extrusion. Use a an M4 x 8mm button head screw and slim T-nut to secure the coupler to the 2020.

Idler Pulley Assembled

Here's the final idler pulley assembled.

This guide was first published on May 07, 2019. It was last updated on May 07, 2019. This page (Idler Assembly) was last updated on Dec 05, 2019.