profiled rail wich preload do you use ZO (light) ? ZA (Medium) for a diy router ?

Hi !
I'would like to order 20mm Hiwin profiled rails for my diy router
build log here:
http://www.mycncuk.com/threads/8717-...area-first-cnc
i've read many posts but it's realy hard to know wich preload ordering, some posts looks like NASA calculations with torque etc, cetainly the best way to know what is required, but too complicated...
I may change the Aluminium frame to a 60x60 Steel Frame.

wich preload are you using ? Have you tested the two ZA and Z0 preloads ?

Hiwin documentation p96 section 2.6.5
http://www.hiwin.fr/images/pdf/cat_e...9TE15_1104.pdf

Attachment 17016

Thanks for your help and happy new year !

For a CNC router, like you're building, I would go for 'ZA' (medium) preload. Preload results in higher stiffness for the bearing, at the expense of reducing the life and increasing the driving force required. These two factors are both negligible for the vast majority of home builds, so getting bearings with zero preload would make little sense.

There are stiffness values in this datasheet, if you want to compare - though they are for different bearings the general trend will be the same.

Yep ! thank you !