The idler can be bedazzled with a 6mm diameter rhinestone and 3d printed spikes. The rhinestone is press fitted into the cavity in the center of the pillar. I super glued the spikes to the groves on the side of the idler. The idler uses a precision ball bearing and 3d printed wheel to function as a pulley system for the rope.
Press fit the wheel over the ball bearing (size 10 x 15 x 4mm). Place the ball bearing over the pillar in the center of the idler. Press the bearing through the peg to seat the wheel to the idler. It should rotate and spin freely.
The idler needs an adapter piece in order to mount it to the aluminum extrusion. Place the idler over the adapter and line up the mounting holes. Use two M3 x 8mm long button head machine screws to join the two parts. Hold the parts together and drive the screws through the mounting holes. Fasten and fully tightened.
The idler adapter is secured to a mounting bit that is designed to fit over the aluminum extrusion. Use two M3 x 6mm screws to join the adapter to the cap. Place the cap under the idler and line up the two mounting holes. Hold the parts together and drive the screws through the mounting holes. Fasten and fully tighten.
The cap can be secured to the aluminum extrusion using an oval t-slut and M4 screw. These are designed to slide into the t-slots. Insert and fasten an M4 screw through the mounting hole on the side of the cap. Twist until thread is half way through – Insert oval t-nut and fasten.
And now we have our pulley assembly ready to install. The bottom of part the idler is called the cap because it will be fitted over the aluminum extrusion essentially capping it off.