Quote Originally Posted by mart154 View Post
Here's a picture of the new "PFC" to explain the "apart bit."

Tho I just realized that the number "75" should be actually 100. So many errors. Embarrassing....

So I gather that would be fine?
Apart from it looks like there's not enough room for the ballnut.? . . . Have you accounted for it.?

Quote Originally Posted by mart154 View Post
Or would it be any good if I leave the bottom bearings on the gantry with 150 (or 200) spacing and do the top one say 300? (just to get the cutting area that little bit bigger?
Yes I'd have the top wide because you can and it will help and have the bottom most you can spare.

Quote Originally Posted by mart154 View Post
I just realized that profiled rails might actually be in my price range. Have to think and choose.
Well if they are within reach then stretch to them because they are in another league to round rail. 15mm will easily handle the loads but the bearings are not always ideal due to there smaller size but they will easily do the job.