Remixed from hinge's 'Polargraph - timing belt and spring load' design: https://www.thingiverse.com/thing:1733420
This remix fixes some alignment issues with the tensioner arm, improves tension spring retention, strengthens the mounting plate, and makes a few other refinements.
UPDATE: Now includes two versions of the motor mounts -- for 33mm and 40mm height NEMA 17s.
Polargraph / Vertical Plotter motor mounts with belt tensioners. These will mount Nema motors with a GT2 timing belt setup to a wooden frame.
The benefit of having belt tensioners is that counterweights are not needed at the end of your timing belts (of course you could add them if you like).
Left and right motor mounts. Tensioner lever -- you'll need to print two of them. End cap for the belt hook studs if you're worried about them sliding off -- you'll need two of them. And a belt wrap post that's useful for belt storage.
- Use this guide to learn all the technical details about building a Polargraph printer.
The recessed holes for the motor mounting screws can be challenging to print correctly since they have a 90° overhang.
Cura has a setting called "Make Overhang Printable" under the "Experimental" section. That'll make it print well without supports.
(6) M3 x 16 screw - Spring holder, tensioner arm hinge, and bearing. The bearing screw could be as short as an M3 x 12.
(4) M3 nylon lock nuts - Tensioner arm hinge and bearing. You could use lock washers too.
(2) M3 washers - Between the bearing and tensioner arm.
(2) 623 Bearings - 623-RS or 623-ZZ, whichever flavor you want. If you're feeling really adventurous, download and print functional 623 bearings, but no guarantee on how well they'll hold up.
(2) Compression Springs around 20mm x 8mm - The stock bed leveling springs used on Creality printers (possibly others) work perfectly, so if you've upgraded them use the old stock springs.
(4) M3 x12 screw - Stepper Motor mounts
(6) #6 x 5/8 wood screws with counter sunk head - mounting to a wood frame
To finish off a polargraph project you'll need these: