MakerSlide carriage plate for steel V-wheels

This is a slightly different version of the standard MakerSlide carriage plate.  It is thicker (4 mm aluminium), slightly narrower (85 mm x 160 mm), and has a hole pattern that works with the single-piece V-groove bearings.

It is not compatible with the Delrin V-wheels, nor with dual-bearing steel wheels of the same dimension (e. g. the OpenBuilds steel wheels).  It is only for the RM1ZZ-derived bearing that we carry.