The drawing does not call out that the screws need to be threaded.
The original part did not have the lead nut mounting screw holes tapped, it was assembled with some longer screws and M3 nuts. This allowed a bit of adjustment in case of binding. I then changed the part to have m3 tapped holes on the 5 prototypes and never had a binding issue, but I never updated the drawing to reflect this change. This drawing was sent out to JMT so that is why the alpha/beta parts will not have these holes tapped.
So, the alpha/beta units will have thru holes with the lead nut mounted using 2mm longer hardware and M3 nuts (with loctite). This will function just fine but for production units we should have the tapped holes in the carriage.
i have updated and revved the drawing to reflect this with R231:61c011656b6d