Pulling an old HP printer to bits for parts, and it suddenly turned into a CNC machine conversion. Took me 4 days, but there were a few small hurdles to overcome. The brains of it is an Arduino Uno with a Protoneer CNC shield running GRBL. (Big shout out to https://info.protoneer.com/1)
The Z and X axis runs on ball bearing drawer slides, and they have absolutely no vertical or horizontal play.
The threaded rods run through MDF thread inserts and using a small piece of 6mm acrylic for a ‘nut’ to lock it into the mounts. The inserts don’t seem to have the same amount of backlash as a standard nut.
All electrics (incl a PSU) is at the end where the ink carts used to be.
The X axis is a bit noisy because it is mounted to the printers steel base plate, but some nylon washers should dull that down a bit.
The dremel flexi-shaft runs down the inside of the 1″ square tube (the bit the pen was zip tied to) on the Z axis.
PS…I’ve never attempted anything like this before, I’m still learning about the whole CNC thing (spot the sticky notes to remind me what axis I was moving!). The fact that I could use the original bodywork (panels) was more good luck than good design….except when it comes to drilling holes for USB cables. That was just crappy “eye-ometer”.
UPDATE: Here is a blog I wrote up about the build, including the first runs.
https://justcheckinm8.blogspot.co.nz/
Step-by-step mechanics reveal that Usain Bolt hits the ground with a peak force of over 1000 pounds with his right, but not his left leg in these steps from this high-speed race footage from NBC Universal Sports.
Ground forces were determined from Bolt’s gait mechanics using a new method described in this video: https://youtu.be/PfHNOwmmik4 and fully explained in this research article: https://jeb.biologists.org/content/early/2016/11/02/jeb.138057