[M.D. Holloway]

928RAM - Nylon may not be your best material option here. Nylon has its properties but it also has some disadvantages namely that it is not as abrasion resitant as some other polymers and it does absorb about 4-5% water. The dimensional stability can come into question for applications that are rather dependent on tigher tolerences. The machining isn't as forgiving compared to other polymers either. Some ideas would be:
1) Delrin: thats an acetal resin from du Pont, its a thermoset so once its cured thats it. You can get it in block form ready for cutting.
2) Polyurathane: many different to choose from. Some are very stable and resistant to oil and fuel and can be machined. These are considered a thermoset as well (but soemtimes they are considerd thermoplastic - long story). They can be cast into a mold or they can come in block form for machining.
3) Filled Polyetherimides: thermoplastic, these are used in everything from jet engines to food packaging. Not sure but I think you can get these in block form as well.
4) Elastollan: a polyester polyuretane from BASF. It is used in under the hood applications and is machinable. It will also have some good resistance to oils and grease. Call them at 800-892-3111. Try to get to tech service. when you get to the right person, see if they can send you a sample to test. You won't need much.

You may also want to give GE Polymer Shapes a call. They used to be Cadillac Plastics but GE bought them out. They can be reached at 866-437-7427.

Let me know what you find out.