[minichopper6hp]

I have the sbr chinese supported rail on my machine build, and it seems like there is excessive play on the rails between the blocks. I know they have a preload screw, but when i tighten it slightly, the rails lock up. Poor quality or what? Need opinions!


Here is one like i have:

Linear Bearing Slide SBR12 1000mm 2RAILS 4 Blocks for CNC | eBay

[interzis]

yes, the carriages are not very strong
supported rail is good enough for hobby purposes but the carriages are awful
try to use 3 or even 4 carriages per rail and soft tight the preloading screw

[louieatienza]

Never used them, but I would remove the preload screw and examine its end to see if it is irregular. If so it might cause excessive tightening with just a small turn.

[FandZ]

I have the 20mm version that I purchased from Glacern to use on a second machine. While researching them I read a lot about cheaper blocks needing to be shimmed. You should also look at your machines rail alignment and not just the blocks. As you tighten the preload, you are also tightening the tolerances of your machine. Could be your rails or mounts to the blocks are just a little out of alignment and when you tighten them they are binding due to other variances within the machine. A cheap dial indicator should help you hunt down the problem.

[GeorgeIoak]

Take a look at the seal on the ends of the block. I just received some from China and the rubber seal was perhaps not trimmed and it caused the block to stick. I was told to trim the seal, I did on one and that fixed the problem but that doesn't seem like a proper solution so I'm trying to find more information about this issue.