okay, my background is architecture/woodworking, so i am not conversant with mechanical practices, theory, and common solutions that many of you pros and high-end amateurs are experienced in, so don't laugh too hard at my stupid newbie questions... (you can laugh some...)
1. on many designs -including the 7th sojourn of JOHN CONRAD KLEINBAUER (inventor of the homebrew cnc (sic))- there is both an end support where motor(s) and/or end bearings for the drive shaft are attached, *and* a motor mount plate of some sort... (here's the stupid part) what function does the motor mount plate serve ? why can't you just mount the motor directly to the MDF/alum/plywd/whatever end support itself and call it a day ? (i can see that you need a separate mounting block if you have the rod/rail suspended by the 4-screw adjustable mount, but otherwise, it just seems to be an extra piece of stuff for no apparent purpose)
2. for the delrin/whatever 'nut' to attach to the backplates being driven by the threaded rod, is there any benefit to making that nut somewhat (or much?) thicker ? would it help absorb potential 'whipping' actions of the rod (especially as it got longer) ? would it be more betterer if you had TWO such 'drive nuts' at each end of the moving table (or the other axes) ? would that distribute forces better ?
3. in contemplating the problem of attaching motor shaft to threaded rod, is there a possibility that making a coupling out of delrin or other high density plastic stuff would stand up to the forces involved, yet provide the -apparently necessary- flexibility to allow for misalignments ?
i am thinking that taking a block, drilling for the diameter of the motor shaft on one end, and for the rod diameter on the other end, then just glopping it up with some epoxy *should* (?) work okay... besides the drawback of being made a 'permanent' connection with the epoxy, would such an arrangement work okay ?
4. for an approximately 16"x24" moving bed machine with a dremel that is intended to do wood (and maybe some plastic/acrylic), what would be a good range of 'power' (ie oz's of holding force) for the motors to be ?
5. don't laugh too hard, but i am thinking about using a set of drawer slides (actually, they were used for a trash rollout) as the 'linear bearings' for at least the sliding table. they are of a high quality and have virtually zero slop in both axes (side-to-side and up-and-down), and is already in a pre-made frame that i just have to stiffen up with a couple pieces of plywd, slap on a table, drill for the rod to come through one end, and i've got a sliding table for little effort and expense... it *does* have a slightly variable resistance when one portion of the full-extension slides pull out far enough for the other portion to engage, but i'm not sure if that is an insurmountable problem or not...
any advice, speculations, and warnings are appreciated...
thanks
charley
charleyy@alltel.net
eof