Gibbs and Ways OR Linear Rails

[jbolt]

as someone who just converted a hobby mill from dovetails to linear rails I have (biased) opinions on this, haha.

Linear rails have the advantage of not needing to be adjusted. Dovetails inherently have a small amount of slop to keep them from binding and to provide a place for the lubrication film. And as we all know, where there is clearance there is adjustment that needs to be made to maintain that clearance as things wear. This also means if things are too tight you loose your lubrication film which induces premature wear and can cause binding, and if things are too loose, you will get excessive vibration and poor surface finishes. On the flip side linear rails can come with a preload in the bearing already which keeps things nice and tight all the time. I just got done with my conversion and I'll never go back. In fact, I'm so tickled with them i got a set for my cnc lathe as well.

I suppose i should also note that I did not get cheapo chinesium rails either. I spent the money and got nice (used) NSK rails and bearings.

Did you document your conversion?

 

[cs900]

I certainly did:

https://www.cnczone.com/forums/benchtop-machines/349850-pm45-mill-upgrades.html

 

[jbolt]

NICE! Thanks for sharing.

 

[cs900]

you're welcome! I'm going to be starting my lathe pretty soon as well so keep your eyes open for that thread.

 

[hanermo2]

All HAAS machine use linear rails.
D: I used to be the country commercial sales manager for a HAAS HFO- best in the world about 2012-2013 iirc, Spain.

All my builds use linear rails.
The *right choice* is to use bigger rails and more blocks.

Every maker of rails explains how more blocks reduces error and wobble .. essentially making the toolbit path more rigid and accurate via geometric averaging.
The easiest cheapest best way for diy is linear rails, a bit bigger, for much better results.

My new VMC uses double rails, 35 mm, 2 on both sides in the vertical columns of the z axis.
It is a double column machine.
So 4 rails / 8 blocks total at the front where the spindle is, and 2 rails / 4 blocks backside.
It makes the linear way about 20-100xx more rigid and more accurate.

The 50 tons capacity leads to 1 tons actual usable load.
Like every lathe and mill.