Quote Originally Posted by jonnie View Post
I would follow advice regards rail choice from more experienced builders but at the same time I would always strive to isolate rails as much as possible from dust of any kind as I dont think that bearings and dust are great bedfellows period - ok metal swarf may simply be pushed along as the vee ways on my old Boxford demonstrate but instinctively I would not trust any linear bearing against the ingress of plasma or wood dust without secondary physical isolation.
Yes that's good and should if at all possible be done but no matter how well you ventilate or try to protect them there's always a certain amount of dust that gets on the rail and my point still stands in that the cheap round rail bearings can't handle it for very long before getting baggy and sloppy. They wear quickly enough with wood dust but with fine metal powder dust they will run for the hills very quickly.!!

Profiled linear rails have Wiper seals built into them that greatly protect the bearings, infact they are similar to the V wipers on the Boxford (I have one too) but much better. When you experience profiled rails you won't ever build another machine without them.!! . . . . I won't entertain building machine using Cheap Round rail anymore has it's more hassle than it's worth.