OrangeA Linear Rail 2PCS SBR16-2000mm, 2xLinear Guide Rails and 4X Square Type Carriage Bearing Blocks,CNC Rail Kit

I recently bought a stereo microscope head and needed a stand for it. The best stands are double arm boom stands, which use two linear rails. I have a 3D printer, so I figured, why not just build one? Looking at McMaster-Carr, linear rails and pillow blocks are EXPENSIVE. I looked elsewhere online, and they still weren't anywhere near what I wanted to pay. So then, of course, I checked Amazon and found these. I probably could have gotten away with the 16mm rails for my application, but I decided on the 20mm x 1m.First of all, they're super heavy. I guess that should be expected. They have a nice coating of oil on them, which seems to get on everything like anti-seize does - nothing a little brake cleaner can't take care of. The rails are straight and have a nice polish, and they measure 20mm +0.1/-0.2. The ends aren't chamfered, which would have been preferable, but that's an easy fix. The pillow blocks seem well made, with recirculating ball type bearings in them. Putting the two together, the blocks slide nicely on the rails, though they're a bit loud. The dust seals on the blocks seem to be well-fitted and there's no discernible play in the bearings.I need to cut these rails down, and I did so using an angle grinder with a cutoff wheel. I then polished and chamfered the ends with a 120 grit flap disc. Cutting took a couple of minutes per cut. You could probably do it with a hacksaw but it'll take you all afternoon. Out of curiosity, I tried drilling into a piece of the rail and I was able to drill without too much problem, so the rails aren't too terribly hard.Overall, these are a great choice if you need a set of linear rails, pillow blocks, and mounting blocks. I'll be posting my build to Hackaday and thingivese, and I'll be recommending these rails to anyone looking to build their own microscope stand.

Works great for what I needed, though heavier then I thought it would be. Very strong and slides very well

So the rails in general are great. Good quality, sliders are fine. The only downside for me was the weight. They weigh a lot and that is why I returned them.

They worked perfectly, Easy to install they came earlier than expected, but yeah very satisfied. I installed the 40 inch rails w/bearing blocks that I bought through Amazon weeks earlier with my router attached to them,so my router system is completer and works smoothly very happy ty

These rails are very nice for the money would recommend to anyone.

The media could not be loaded. I got these to build my own router sled for a fraction of the price that other companies offer it for. They work great and slide without issue. Just attach them to something stable like the 3/4” plywood plus melamine screwed together like I have and it will stay put. As long as you take your time when placing the slides, you’ll be good. I plan on getting the long rails too to try and build a full slab flattening sled as well.

These are very sturdy rails and though I don't have them up an running yet, I can tell they are going to do well. They are of high quality.

Absolute garbage product. The cubes are not balanced so if you use them as a single track they fall from side to side and get stuck instantly. Impossible to use as a single unit, you have to use two tracks side by side, which for many uses invalidates the use. If the rail was oval instead of perfectly round than it would work as intended but due to the round rail, and poor design of the cube slider, it does not work as intended at all.