[wood booger]

I have been been turning glass filled POM recently, and if you take a small finish cut it can put off some very small particles.

Wear a mask, you don't want to breath crushed glass particles into you lungs. No Bueno.lthumbsdown:

 

[ohio]

Ohio,
Did your PTFE headset work? Be a little heavy in the steering??

Heh, theoretically.

 

[buildyourown]

Funny reading all this... I designed a bike in 2000/01 to use PTFE bushings for the headset. Even more appropriate application since steer tubes don't turn enough to refresh the oil film on any kind of headset bearing especially under vibrations in a straight line.

I built one of those a long time ago, before I knew anything about machining or tolerancing. It didn't work for ****. It just had way too much drag. It would be interesting to make another one now knowing what I do about materials and manufacturing. In hind site, it probably would have worked on something like a DH bike where a little natural damping isn't the worst thing.

 

[atrokz]

After machining 3D profiles in Inconel, there isn't a plastic out there that's hard to machine.....

-Similar cutting tools to aluminum with regards to rake angles, # of flutes, helux angles, etc.
-No Coolant is needed
-RPM base is determined by the materials SFPM which is usually FAST. Up or down depends on variables such as machine, set up, cutter used, etc. Keep in mind, that it wont make a difference using HSS or carbide tooling with plastic. It never gets hot enough to warrant the NEED for carbide.
-Feeds are determined by the chip load you're looking for. RPM x Chip Load per Tooth x No. of Flutes. Determine the chip load by the cutter you're using.