Slant bed lathe Z axis 4 way load rails?

[will gilmore]

Im planning a lathe maybe slant bed. For the Z axis do I need 4 way loading rails (THK SHS, HSR) or can I get away with "horizontal" loading rails (THK SSR, SR)?

[Jason3]

For a horizontal axis where the main force is directly down through the rails, the SSR type actually offers greater rigidity than the SHS (or HSR) type of an equivalent size. As soon as the axis is not horizontal, or the forces are acting from other directions, the SHS or HSR type are better.

If you possibly can, go for the caged ball type - SHS or SSR - not so much for the longer life, but they move MUCH more smoothly, and can really help your surface finish and accuracy.

Best regards,

Jason

[will gilmore]

thanks for the reply. I didn't know that SSR/SR was more rigid than SHS/HSR. good info

[Jason3]

Well, only fractionally There's some interesting reading here: http://www.thk.com/documents/us_pdf/...chmodel_cb.pdf

I liked the example of a durability test with an SHS type caged ball system - it still looked ok after 30,000 Km travel, with only an initial lubrication.

Amazing stuff...

Jason