New parts: gantry, leadscrew axial shims, and Z axis stepper mount

Post date: May 23, 2016 9:46:44 PM

A whole batch of new parts. The big one (literally and metaphorically) is the gantry. It's been squared up to the right length and had holes drilled (and tapped). More on that in a bit.

The second-largest part is the plate that the Z axis stepper sits on. And the little parts are shims to go on the leadscrews. The bearings I got are shorter than the non-threaded portion of the leadscrews, so in order to clamp down on them, I need a shim in there. That's what all the little round things are. Strictly speaking, I really have no reason to need to do anything to the ends of the leadscrews, since they're going to be held in place by the bearings (which will be clamped at either end, so the leadscrew can't slide anywhere). It's more a matter of principle... And I already got the (oddly-sized) nuts for it, so I might as well.

Back to the drilled/tapped holes on the gantry... evidently an M5-0.9 tap is a thing, and I have one (the "normal" M5 thread is M5-0.8). As far as I can tell, it was only ever used on some pre-1972 cars. And when I went to the hardware store and asked for a normal M5 tap, that's what I got. I'm really no sure why they even had one in the first place, and I probably should have double-checked the taps before I left, since the guy fishing them out for me didn't seem terribly with it.

Long story short, those holes will need to be drilled out, and I'll just stick nuts on the back side. Fortunately I can do that with these holes, and haven't tapped any other M5 holes yet. Which is really good, since most of those are blind, and I really couldn't recover from having the wrong threads in them. M5-0.9 screws are nearly impossible to find, and stupidly expensive (like $2/screw), so that's not really an option.

Anyway, it's progress, with some frustration. On the up side, I think there's only somewhere in the mid-teens of parts left to machine...