/diy/ - Do It Yourself

In my opinion the most viable option is using boxways. Pic is my first rapidly cobbled up prototype plz ignore the scratches, random holes (scrap steel pieces), bad machining marks and shitty scraping.

The results were:
-steel is a huge PITA to scrape
-you'll need to start with a good surface finish. It takes forever to scrape down the machining marks if you didn't give a shit preparing the blank.
-besides i didn't even scrape this anywhere close to perfection but it started to work as a rail after just a few correction passes. It's still out at most like 0.05mm (0.002") one end and binds up but the rest is ok.
-As soon as i put way oil in it you can really feel how stiff it gets and how it dampens everything
-Tried to rock it with maximum stickout to check for play. I just get a little movement (without way oil) under 0.01mm.

This is after a little bit of scraping without much attention to anything, which tells me if i actually do give a fuck it's definitly a route to makeing useable rails.

Why steel boxways:
-Boxways should be stiffer as linear rails the same size, which i think should be very important for small machines
-Steel is abundant pretty much everywhere on the planet. If i actually come up with a working concept, it's easy to replicate. Cast iron bars are hard to get and expensive.
-Steel bars are super cheap
-Wear properties shouldn't be too important in the homeshop
-Easy to scrape for geometry (no dovetail angels) and easy to measure
-If you constrain the slides by a third rail in the middle (which is done by expensive machines to get even, symmetric thermal movement similar to using two front bearings as axial fixtureing point in spindles) you just need to scrape 3 rails flat and parallel. No angles at all. I'm not sure if this really is less work than to make an right angle master and scrape the sides, but i know, that small rail sides are hard to scrape. Geometry then is in aligning, not in scraping (should be easier).