Guys, how would you mount a stepper motor under and along a square tube like shown in the pic below? I am not very confident in my current design as it is (http://www.thingiverse.com/thing:1487375).
Please don’t suggest extrusion (I have that in works), I am interested in doing this variation with square tubing.
@Rien: That might actually work. I knew about these but I just now realize that the slots are 31mm apart while the square tubing is 20mm apart so I might get some bolts up in the slots and fasten with another plate on top of the tube…
Plenty of hot glue and then more hot glue piled on that, that’s how I’d build it.
I just don’t trust that much my design for the Z motor mount… it will rock around the plane where the screws go through the plastic into the motor as the motor changes rotation direction. Granted, it shouldn’t happen with a level bed where auto-level compensation is not employed and the load would basically be in one direction only as the bed descends layer by layer…
I would use a formed sheet metal piece. Its the only way to securely place and secure a motor like this. We normally do a custom one however I have idea if you can get an off the shelf piece.
U-bracket?
@Rob_Palmer
I asked how would you do it to pick your brains regardless of my wishes. I need a simple way (plastic or metal) that would securely mount the motor to the above square tubing without being too flimsy during normal operation.
I have also specified one constrain and that is that I would like not to put holes through the tube but to use some sort of clamping for the job.
@Ross_Bagley
Forgot to answer this:
3DHubs seem very expensive in this area and I didn’t consider this when started designing the #SCOUTcorexy; I had access to 3d printers at the time. Now I see the need to be able to build the first printer with (if possible) zero printed parts, a simple enough printer to use and print the parts needed for a bigger, more complex printer.
I am trying to replace some printed parts with something I can easily adapt so I can later on print them like I intended.
@Rob_Palmer
I don’t get it, after your first answer I said I want to go around the tube (clamp?) as I don’t want to put holes through the alu square.
And I appreciate all the answers, I don’t necessarily want the answers I am also able to imagine, but something that I might not think of or not know about.
@Ciprian_Balalau_Make BTW, your (all?) metal cantilevered design looks better and better for a printer to start with, apart from having a friend do the printing for you 
I just moved here, haven’t got the chance to meet any yet but there is no maker space or any apparently visible organized movement in the city. Yeah you could tell I want to repstrap but basically @Rien_Stouten 's suggestion is a good one and that’s a normal Nema17 mount, no rep-strap there. I have though the possibility to get one fabricated. It’s funny that 3d printed parts are expensive while I can have some friend of friend make one from sheet metal basically for free.
BTW my design is no repstrap at all but I didn’t envision issues that one might get into when not having another 3d printer to start with.
@David_Clunie
A flared out U-bracket would work, something along these lines: http://cdn1.bigcommerce.com/n-ww20x/2454y/product_images/uploaded_images/joist-hanger-4.jpg. I’d have one on each end of the Nema17.
