operation cnc

[kingcreaky]

now I am confused! I think im going to have to read your post another 100 times slowly to understand, then study the pdf. perhaps im not asking the right questions? or perhaps relying too much on telepathy
Essentially you have succeeded in making me aware there are different 'types' of ball screw housings. I think what your saying is the ones ive detailed above (which incidently I havent yet bought anything) are for a fixed screw arrangment, and if I want a spinning screw I need to re-think my choice of screw housing? once again, one question results in ten more :D sorry

[irving2008]

now I am confused! I think im going to have to read your post another 100 times slowly to understand, then study the pdf. perhaps im not asking the right questions? or perhaps relying too much on telepathy
Essentially you have succeeded in making me aware there are different 'types' of ball screw housings. I think what your saying is the ones ive detailed above (which incidently I havent yet bought anything) are for a fixed screw arrangment, and if I want a spinning screw I need to re-think my choice of screw housing? once again, one question results in ten more :D sorry

Nooo... Imagine the screw is a long bendy pole... the faster you twirl it the more it flaps around. To stop it flapping you need to constrain it. The way to do that is to put bearings at each end. The bearings are fitted into bearing housings. The one at the far end has a single bearing in it, the one nearer the drive end has two bearings. The single bearing just supports the screw, it doesnt stop it moving end to end (axially). The double ones stop the screw moving end-to-end, hence 'fixed'. Both types allow the screw to turn! By putting a 'fixed' one at the far end as well controls the whip a bit more but it needs a different end-machining of course.