Plastic Selection - 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 Aluminum, 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 Aluminum 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 Aluminum. Is there a Chemical guy on here who could suggest a good plastic for me? Naturally, the material would need to be oil resistant and withstand typical engine transmission temperatures. ![Location on Transmission][2] Update: - Apparently, I never updated this thread. What did I wind up doing? Instead of having something cut out of a polymer, I simply welded an aluminum tab to the aluminum derby cover. ![Welded Tabs][3] Then, I hit them with some black engine paint: ![Black Custom Covers][4] I've been running this setup for a couple of years now: ![Custom Dirby Shifter][5] [1]: https://i.sstatic.net/tOcvX.png [2]: https://i.sstatic.net/X7D2T.jpg [3]: http://i.imgur.com/LHqq860h.jpg [4]: http://i.imgur.com/atH2riHh.jpg [5]: http://i.imgur.com/JTNG9XFh.jpg