Comparing Linear rails
MGN7H Slide and Rail
150MM Long
We have finally found rails of high enough quality to offer for sale. As you can see in the pictures, some rails do not look like they have had their final grind. Some the wipers do not even touch the bearing surface of the rails. And others are simply ground to a chamfer instead of a radius giving single point contact. This will surely lead to premature failure. A few words on each problem:
No final grind - The running surface will be rough. The wipers (if they even touch) will be ground away on the rough surface.
Wipers don't touch - The point of wipers is to wipe debris away as the carriage moves on the rail. This will not happen it the wipers don't touch.
Chamfer bearing surface - the balls will run on a single point. In a short amount of time the point will flatten causing the carriage to have too much play.