Ok, I finally have sufficient parts to make a run at this…but I have found a possibly significant problem.
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I want to built a mantis, or at least mantis-inspired CNC for simple PCB prototyping. I have almost all the parts in the Mantis BOM except the spindle and bits[1], but that’s enough to get started… (and yes, I’m going to use plywood rather than my originally planned MDF, I’ve read about the poor holding of ‘end grain’ in MDF),
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except that the Mantis instructions assume that I have some means of drilling a hole in the center of my threaded rod to glue the steppers into. Various problems with that are, don’t have a lathe to drill perfectly centered with, don’t have access to any other CNC equipment to drill perfectly centered with, and today when the steppers arrived, I noted that the threaded rod diamater is only about twice that of the shafts on these particular steppers. That worries me.
So in no particular order:
I have a drill press, is there a recommended way to make centered holes in threaded rod with one, instead of using a lathe or similar? I’ve had some ideas occur to me but I’m not very confident I won’t just screw up my rods…
Is there a better way to couple the steppers to the rods? One that doesn’t involve drilling what seems to me a really huge hole that needs to be pretty perfectly in the center of the rods? If you’re interested I will go measure them but right now I should be sleeping and they’re in the basement 
[1] ack, I just realized I don’t think I have the stepper drivers either 