Judging by your videos, you've already done much of the stuff I've only dreamed about. I like that (gingery, is it?) lathe. Seems like you're more of a 'doer' than I am. I really have to push myself to not sweat the small stuff and just do it. I did manage to get into some pot-metal and aluminum casting for a while there. I'd love to see your foundry if you ever care to share.
The questions I mentioned on YT will mostly be formed when I know what they are. I foresee a lot of them as I haven't even used skienforge yet for example. I have drawn 3D things in sketch up but I don't know how to correctly generate 'closed' STL objects and such.
To answer your questions, I bought the generation 3 electronics kit from makerbot way back when. It came with a sanguino based mother board, stepper driver boards, and a bunch of trimmins. I have nema 23 steppers (I forget the torque specs n' stuff, it's been years!). I have a nema 17 that I hope to feed the extruder with. (Obsolete) hot end parts (nichrome wire, PTFE rod, etc.). I wanted to direct drive the lead screws instead of using belts because of backlash but I'm not so sure I can get away with driving that heavy table without belt drives. I'd like to hear your thoughts on that. My original intent was to make the thing rigid enough to rout (mill) with so that I could have the extruder and a dremel on the Z for simultaneous additive AND subtractive capabilities. I'm wondering if I'll need to counter-balance the Z axis because of the limited torque of the stepper.
The acme threaded rods are 3/8-16 single start. They were going to recycle them at work so I said score! I found anti-backlash nuts made by a guy on the cnczone forum. I'm using two angular contact bearings slightly preloaded on one end of each lead screw to eliminate slop. The other ends will just 'float' in a regular skate bearing to keep them from whipping and allow them to shrink and grow without sagging or getting tight.
I'd really like to have linear magnetic encoders because of the somewhat rough tolerance and thermal expansion and contraction of the lead screws. I've read that their resolution is about .0005 Do you know how they interface with the electronics?
Anyway Jeff. Thanks for your encouragement and gracious offer to help me with questions.