Here’s a great CNC hack that adds a ton of functionality, a DIY rotary 4th axis!
[Jim] had started this project over a year ago when he originally ordered the gearhead off eBay, but like many good intentions, sometimes projects just get pushed to the back burner until necessity forces action. That necessity was entering our Trinket Contest, and he decided to finish it off just so he could put a HaD logo on a piece of PVC for us!
Unfortunately it took him a bit too long, and he only finished it last week — but luckily he had a fallback plan, and submitted his CNC Etch a Sketch project instead, which won him a Trinket anyway!
The 4th axis uses a 276oz-in stepper motor which is directly coupled to a Harmonic Drive Systems 11:1 planetary gearhead. It’s extremely accurate, has minimal backlash, and by using a 10 microstepping Gecko stepper drive, [Jim] is getting about 61 steps per degree of rotation. Not bad for a home-made setup!
Check out his blog for a great write up on the project, and stick around after the break to see the 4th axis in action.