You can add a rotary axis. However, you will have to use either the X or the Y stepper driver. In other words, you will have to unplug one or the other to plug in your rotary. The "normal" grbl can not handle 4 different axis at once. I am currently in the process of doing the opposite. I built a rotary axis CNC that has a large Z travel. I found some projects where I needed 150-175 mm of Z travel and I realized I could buy a Cbeam linear actuator, unplug my rotary, plug it into the linear actuator, reset the steps per mm in grbl settings, and now I have a Cbeam CNC with over 225mm of Z travel. I have also sourced some 8mm diameter/200mm long endmills. I am completely aware that there will be deflection, but on a wooden beer stein, I don't think it is critical. Nothing I plan to do (bowls, steins, etc...) are to me manufactured to aerospace tolerances.
If we use X or Y axis, how does GRBL know if the steps are per distance or per degree? Or does it matter?
Your CAM essentially uses mm as degree. See Post #26 in LEAD Lathe Or grab the newer BlackBox X32, that runs on the newer grblHAL and has proper 4th (A-Axis) support docs:blackbox-x32:start [OpenBuilds Documentation]
O okay so say for example if I have a 3inch diameter round cylinder, If I put in the GRBL parameter file the number of steps per inch to make one full revolution. I guess the machine will still know the number of steps for say a 2 inch diameter cylinder? I have been looking at the X32 my setup had two motors for Y, one for X and One for Z. Wouldn't the X32 need five stepper drivers? Can I combine both the Y motors on one driver? The image below is from the open labs home page. Is this CONTROL application connected to the X32 running GRBLHAL? I notice there is an option for the A axis in this screen shot
You put the stock diameter in CAM. The cam calculates "degrees" (steps per deg/mm interchangable as shown in the link I shared) to move to traverse the distances needed to perform the cut
" Brian002, 30 minutes ago Last edited: 8 minutes ago " Avoid editing after someone replied We don't get notications when you edit. Correct. Ys in parallel, Y2 becomes A. With the newer controller you get the full 4th axes setup (With the older stuff and "wrapping" you get 2 axes (X and Z) + rotary = 3, not 4th axes either)
Sorry about that, needed to refresh my page. Thanks for the help, I am trying to get true 4th axes to make some propellers. As far a the the two Y motors in parallel, is over powering the the stepper driver a concern? I am running NEMA 23 on the Y axis
Then you need the X32. No need for concern, some of our machines parallel 3x motors on one driver (eg the 3x NEMA23 Z-Motors on the Triple-Z Multi-Z Add-On for LEAD 1515)
Thanks, With the X32 by default will the X, Y, Z, A jog control be available in the open builds CONTROL app? I just not seeing much in the manual for rotary axis setup.
