[Power_user_EX]

Hi all. I am designing a CNC 1st time and need help with choosing shafts for linear motion. I am stuck between these sizes:
1) Shafts having diameter of around 16/18mm
2) Shafts having diameter of around 10/12mm

Is using shafts of bigger diameter , for linear motion support , better and stable ?

I will be using open type linear bearings(with housing) with those shafts. My total X Axis length is 500mm and Y axis about 400mm.

[Phife]

Are those supported shafts?

Thicker is better.

[keebler303]

Supported shafts will give you a much better result and the bigger the better.

Matt

[Power_user_EX]

Are those supported shafts?

Thicker is better.

I am planning to use shaft support rails and hence will be using open type linear bearings. I plan to use shaft end support blocks and linear support rails. But I am confused about how the shaft it attached or mounted on the support rails.

Any help on that will be much appreciated.

[keebler303]

Normally supported rails are purchased that are already drilled and tapped or are already mounted to a base rail, like this: http://www.thomsonlinear.com/website.../multitrac.php

Matt

[Phife]

heres another example of supported rails, I dont recommend you try and drill/tap your own rails as its not an easy job to do..

Glacern Machine Tools - Linear Rails and Bearings