I'm going to have an online machine shop build a part for me using a CAD drawing that I specify.

Typically, these parts are made of aluminium, but this manufacturer also mills parts out of these plastic materials:

- Polypropylene (PP)
- Polystyrene (PS)
- High impact polystyrene (HIPS)
- Acrylonitrile butadiene styrene (ABS)
- Polyethylene terephthalate (PET)
- Polyester (PES)
- Polyamides (PA) (Nylons)
- Poly(vinyl chloride) (PVC)
- Polyurethanes (PU)
- Polycarbonate (PC)
- Polyethylene (PE)

Polypropylene, I know, is the plastic used in water bottles, so I know that is not what I want.

This fabricated part will be used for the clutch cover on a motorcycle transmission and will have a raised section that needs to be tapped to allow attaching a gear shifter to, like in the aluminium version below.

![Clutch Cover with Shift Mount][1]

I'd like something rigid and strong. Plexiglass comes to mind, but there could be a better alternative that I am unaware of, as long as I am not getting into something exotic that would cost more than aluminium.

Could suggest a good plastic for me, which would need to be oil resistant and withstand typical engine transmission temperatures.

![Location on Transmission][2]

  [1]: https://i.sstatic.net/tOcvX.png
  [2]: https://i.sstatic.net/X7D2T.jpg