Quote Originally Posted by Juranovich View Post
First off- those are some slick looking machines! Also, I never considered using a cross beam under the frame for dual stepper set-ups.

The round vs profile rail debate is one that has had me torn the most. Undoubtedly profile are superior in theory, in practice, however, I've been somewhat put off by the many worst case scenarios people have posted about when ordering the Chinese kind (which I strongly suspect is the only kind my budget allows). Second, being a first timer, I was hoping to get slightly more parallel mounting tolerance with the round rails (bc self alignment), and they provide more room for mounting ball screws on the same face (although that could also be achieved by spacers on the profile carriages). I'm curious though, in what way do you find profile to be less of a hassle?
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The square rails for me are may be the most important part of the machine in the long run, so there should not be any doubts about that. In fact better buy a smaller size square rails than round rails. mean 15 instead of 20 size , if machine is not intended for heavy duty use . You can always use one carriage more as they are cheap. rail is heavy hence expensive to ship. You get what i say?

About the Chinese square rails, if you buy from a good factory they are same or very similar quality like the Hiwin. You may need to clean a carriage or similar, but most important is to be from a good place.

I buy from these guys https://es.aliexpress.com/store/822038 12 and 15 size. Have not bought from them 20 size , but their rails are very good quality and price. Custom size also, contact them. make sure to buy the long carriages.