View Full Version : SBR20 rails from Glacern Machine tools

04-14-2012, 03:08 PM
Hey all, I’ve seen some questions regarding Glacern SBR20 rails and blocks but I haven’t seen any pictures. I’ve recently purchased some for a build and I thought I’d share some info and pictures. If anyone has any recommendations they like to share on them please do.

The four blocks I’ve looked can vary from .0015 to .02 depending on what you are measuring. But it’s mounting surface that matters and so far the variances looked to be around .0015. For the gantry that’ll I’ll mount these too I don’t expect to have do add any shims. I do expect to have to add some shims for my aluminum router mount though.

Bearing Preload:
One thing I’ve found is they have two adjustments, one set screw for preload and one screw to tighten the open ball bushing around the rail. Maybe they both are for preload, I’m not sure. When you first take them out the box neither of these has been adjusted and there is a lot of play on the rails. As soon as you tighten the side screw for the open ball bushing all play goes away. You don’t have to tighten it a lot either. I know not all SBR20 blocks come with the setscrew on the top but I’m not sure if they do on the side. If you have some SBR20 blocks without a setscrew on the side with some slop, I’d highly recommend you remove the ball bushing and use a drill press to make one. That is if your ball bushing is incased in metal. I believe some of the ball bushing are incased in plastic.

Rubber seals on the bearing block:
The rubber seals look to be intact. No rips or tears. I was surprised to see how well they wipe the rails. I had wiped the rails down a few times but they keep finding dirt and pushing it in little rings to the edges of the rails.

Overall condition of blocks:
I’m guessing these aluminum blocks are extruded with the retainer clips slots machined in later. I don’t think they are cast. If I’m wrong let me know. There are dings on the mounting surface edges you’ll need to sand down. Some of the blocks had puddles of lubricant in the bag they came in others don’t. You’ll need to wipe them down but overall they are fairly clean out of the bag.

The rails
The actual hardened rails are perfect. I didn’t observe any scratches or anything. The aluminum supports are in the typical condition that Chinese machine parts come in. They have a lot of dings and dirt and grime on them. They must really throw those supports around. I don’t however expect to have to shim them or anything. I’m sure I’ll have to take a sanding block to a ding or 2 but overall I’m satisfied.

Rail mounting holes:
It’s obvious the holes were manually machined. All the holes are straight so I think a drill press was used but you can see the scribe marks. I’ve read some have gotten rails from other places with pencil marks on the bottom. So seeing the scribe marks actually relieved my anxiety some. With scribe marks at least the guy on the drill press had a little feel for getting the holes tightly positioned. Overall I don’t think I’ll need to drill out any holes or make any new ones. I expect them to bolt directly to the 3060 metric extrusions I’m ordering.

Right now I’m very happy with what I got over all. I don’t expect to have to do anything other than a little sanding and cleaning here and there. By hand on the rail with a little preload they are very secure. Once I get them on a machine I may feel differently but with the preload adjustments I’m confident these will do very well.

04-14-2012, 03:09 PM
Spec sheet

04-14-2012, 05:56 PM
When I purchased a set of Glacern rails for my small router, I was pleasantly surprised by the extremely secure packaging. The rails arrived in pristine condition even though the delivery people is my area seem to take delight in breaking things.

04-14-2012, 06:39 PM
I ordered 1 set of 340mm and 2 sets of 1540mm. Your right the packaging was secure and well done. I wouldn't call my aluminum rail supports pristine but they are not far from it. Everything appears to be flat and straight. Looking forward to using them :)