Quote Originally Posted by Jonathan View Post
The critical speed for that length of screw is 290 to 650rpm - depending on what bearings you use. That's 1450 to 3250mm/min assuming 5mm pitch screw. I guess 3250 is ok - why are there not going to be any rapids?

I generally go on the if I can make it cheaper I do philosophy!
I'm gonna agree with Jonathan, you will soon get sick of going at those speeds over a large distance, plus going too slow with a fixed high speed spindle means you will burn cutters/material and wear them out quicker.

I generally go on the principle that i make it as good as possible, so it will last indefinitely. An example is my lathe in the video on the home page you will see i used telescopic ballscrew covers they are very expensive and i had to wait 6 weeks for them to be made. The inbuilt seals will not keep out contaminants so a few months down the line they would all be ruined.

Phil