[vandomme2]

I want to try the lathe option on my Probotix Nebula for the first time.

I want to machine 0.50in dia axles (for wheeled toys) from strips of 0.75 x 0.75in thick HDPE (thermoplastic) sheet.
I am assuming I should not use the 3/16 end mills (I am currently using for flat machining) in the air spindle.

1. What cutters are recommended to achieve pretty small corner radii, e.g. 0.02 - 0.05in?
2. What cutters for best surface quality on the axle?
3. What cutters for drilling a small hole (0.20in dia) at each end of the axle. I assume here I can stop/fix the rotation of the part to zero and drill the two holes. I hope I can use the same cutter as for 1) and 2) so as to do all operations with one and the same cutter.

I appreciate any feedback!
Paul

 

[difalkner]

I would think you'd need zero flute cutters, Paul. Not sure why 3/16" wouldn't work on HDPE as long as your speed/feed matches the bit. How long are the axles? If they're very long my guess is you'll need to take light cuts to limit deflection in the center.

For that small radii in the corners you're going to need a really tiny bit and I would probably do it with two bits - one to get the shape and a smaller one for the corners.

David

 

[MEBCWD]

Paul I agree with David about the zero flute cutters for the HDPE material. I also don't know why a 3/16" bit would not work for both the machining and making the holes in the axels. The toolpath you create to make the holes will stop the rotation to make the holes.

About the radii of 0.02 - 0.05 you would need a bit with a diameter of 0.04 - 0.10 of a radiused end mill with the correct radius desired.

I'm not sure where you are looking at the small radii so maybe we need a picture of the axel design you want to make.