I have an older MPCNC (inch). My carriage cracked and I’m thinking about either doing an update or a mod on the carriage… Has the vertical distance on the rails stayed the same or has that changed from iteration to iteration. Off hand what is that dimension.
I’m not sure what you are referring to as “carriage” nor what vertical distance you are asking about. The Primo Core can be used on the Burly, though you won’t get the full benefit. Ryan gives a brief answer here. The Z axis tube distance and the mounting holes remain the same between Burly and Primo, so you can put a Burly mounting plate on the tubes and use Burly mounts on a Primo Core with a Primo Z axis. Note I estimate that the Primo Core uses between 20% and 25% of the total filament needed for a Primo upgrade.
Are you asking the height difference between the outside X and Y rails? I Expect I t’s going to vary by version - C, F, or J. My C version has just a small saddle piece that sits in between the conduit inside the corners. I can’t measure it right now but will try to post something later this morning. I doubt the saddle is 1/4” tall, it may be less than 1/8”.