Direct Drive for A-Axis?

I have a coupler that can connect my 4th Axis stepper motor to the shaft of my chuck. It’s a 1/4″ to 1/2″ spider coupler. I got it at Princes Auto on the cheap today.

Can a typical zylotex or Nema 23 system handle that?



When using an A-Axis I was thinking that I could mount the work piece in two ways. I could have a chuck at one end and a flat plate at the other.

The flat plate would allow me to bolt stuff to it. I guess if it has the right hole pattern it should be easy to make pulleys. I could cut the bore and rough the outside using a 2.5D method. I could add the mounting holes that match the mounting plate on the A-Axis and then finish the pulley or gear on the A-Axis.

I could also mount odd sized pieces with the plate.

I suppose this plate could be made of 1/2″ thick aluminum? I could drill and tap the hole to match the threaded rod that I’m using as the main shaft of my A-Axis assembly.

Does anybody have a 1/2-20 tap?


I managed to get a 1/2-20 threaded rod at Ottawa Fastener today.

It mounts perfectly onto the chuck I purchased to build my A-Axis.

I got a few of these “thin nuts” to mount the timing pulleys.

Now I need an XL pulley and belt. Perhaps a roller for a tension-er.

I already have the bearings and the small pulley for the motor.