Yeah, the TIG got it, the mill will probably get it, and in all likeliness machine #4 will also get it. It's kind of a problem, at a certain point, though right now "real life" kinda precludes too much attempted overlap. I think it can drop-in, especially since I removed my compound and have the rigidity to work with. I'd also looked at flex-shafts, there's one on Amazon for like $100 but I don't know if it's worth the flutter vs a spindle with more bearings, or actually building a spindle and belt driving it with a "spindle". You see why I've never actually attempted the project... Do you need one? Really all you need is to fix a big hole in your casting. If there's a mm or two gap between the fill and the liner that gets filled with oil, what does that matter? Other than it all falling on you when you next remove the liner. That was my theory. As long as you properly lube the liner (even if you don't plan on removing it again for a few years) it should be fine. Yeah, I need a pressure pot too, probably more like 3 gal though, depending on the dimensions. Of course first I need a vacuum chamber because you can't cast resin into non-vac'd silicone, but anyway. Just another one on the list. It's doable. I wouldn't turn wood on a machine lathe, but that's just me. Many people do, presumably just fine. I'd try turning down a PVC pipe, possibly a PVC pipe covered in Bondo (for diameter), before I tried that. Or a steel tube of some kind. Maybe I'd use some silicone too, for easy removal. Assuming Smooth-On are currently operating. Though, I'd argue that you have the exact same risk and margin of error on both methods, but in one method you've glued a piece of wood in your spindle and in the other you've made your spindle liner non-removable until the next time you feel like blowtorching and banging on it. One of these results in a usable mill... Exactly. And I did just move my lathe away from the wall for exactly this sort of hare-brained rear-access scheme. Hardening, annealing, hell, even SMD soldering if I build it right. Needing to chuck stuff in the oven is another one up there with needing to surface grind something. That's my guess. Though I also have additional ceramic caps on the lines, which I may make more permanent along with the NC-ing. Hard to fail closed, yeah. Harder, in terms of signal:noise ratio, to overpower a solid +5VDC (or 12, or 24) voltage, than kick up what seems to essentially function as a floating ground. From what I've read, most mechanical switches are more accurate than we think- even cheap microswitches. I'm sure they're comfortably hitting the 0.05-0.1mm range or under, which is more than enough for an extrusion machine without a toolchanger or other G53-based operations. I have optical switches that were originally going to go on the laser, but I decided fast and simple was better than making a bunch of little flags. Oh yeah, that was the fourth thing I forgot. Those things are pretty cool! Kinda, yeah. I don't know if it'll happen, but apparently there have been Discussions. That was my assumption, tbh. Incredible how eager they are to privatize something so apparently useless, inefficient and wildly unprofitable. I too, like this plan... Mostly for the flag too, actually. The door can have collet holders in it.