This is my new small 4th Axis, not strong or powerfull, but it will let me work with axial designs in wood and plastic.
Looks awesome. Can you show us the other side? Did you drill and install your own rotary bearing?
That’s pretty cool 
I love that. With a spindle lock of some sort, it’d totally be viable for aluminum. I particularly appreciate the through-hole design rather than having the stepper inline with the spindle.
I need one
Any further information on it?
Like parts used and such?
I just made another entry with more details…have a look at that…
Do you have any mechanism for tightening the belt and whaz kind of belt did you use?
The unit was purchased from ebay, and I assume the bracket the motor is mounted on, can be shifted sidevise. Havn’t tried though. The belt is a proper timing belt, and is quite solid, much stronger than needed actually. But that fact also reduces slack I guess.
I have seen a number of these with
a) XL timing belts intended to me moved only in one direction = backlash and
b) a WAY too weak stepper motor, so you can turn the axis while the motor is supposed to hold it steady enough so you can mill on what it’s holding.
You are probably right assuming both backlash as well as weak holding torque. I don’t expect to make high accuracy milling nor hard materials, but this is just to get me started. And if everything from design to milling is working for me, I may have to find a better rotating axis.
I failed doing super strong materials like…candle wax using the original motor.
Replacing the motor fixed this. (don’t forget the new timing belt pulley)
I hear you @Marcus_Wolschon ha ha, thanks.
Ran into another problem. Time came to look at connecting to motor to my Max NC10 controller. It turns out that the motor is bipolar and the controller is unipolar - bugger. Next step is to find a way to rewire the controller for bipolar output on the A axis. The chip’s on the PCB can do it, so I guess its a matter of simple reviring on the pcb. Anyone has experience with this on a Max NC series mill ?
Ohh, no, the chip is not a universal driver chip. The maxNC driver system is made by discrete components and a custom PIC. I’ll probably have to look for a unipolar Nema 23 with 8mm shaft. Anyone have one to spare ?