Xzero Raptor CNC build - linear rail and ballscrew selection

[Mattia]

Hi folks!

I'm slowly figuring out which bits and pieces I need to finish a Aluminum kit CNC router set I received most of* (missing one ballscrew and all the linear rails, plus motors/electronics) years ago. Following some measuring and collecting info from old build threads I've figured out the Hiwin HGR20 series with HGH-CA and HGH-HA carriages, as all the bits and bobs were designed for this. X axis is 1200mm, Y 790mm and Z 300mm.

Local suppliers (DamenCNC in NL or Sorotec in Germany) are eyewateringly expensive; following recommendations from folks here I requested a quite from The main differences are that the local folks provide High accuracy (H) carriages (tolerante 0.03mm); BST provides C grade standard (tolerance 0.1mm). One has Z0 and the other ZA preload. Considering this is an aluminium gantry router that is intended primarily (>90%) for use in wood - although I do want enough accuracy to do detailed shell inlay (guitar fretboards) for example - I would think that the BST C grade with ZA preload should be a perfectly good solution. Am I right, or is there any good reason to spend double the money for higher accuracy linear rail systems?

The ballscrew mounts and measures (and the two big end bearings that I did receive) suggest the machine was designed for a 25mm ballscrew, though I'm not sure what pitch would be appropriate. From what I gather 2510 was the original design spec but I can't really confirm. I'm not really sure about the pros and cons of a 2505 vs 2510 for a CNC gantry router this size (only 1200mm travel)