So I wanted to ask, who of you are using a 4th axis on your OX with a TinyG? I have an extra stepper motor and am planning on setting it up as an A axis. I would like the option to laser engrave cylindrical parts while keeping my beam focal point fixed. I have been looking at CNC wrapper as an option to convert my Gcode to use a 4th axis while using chilipeppr as my Gcode sending program. Has anyone tried this?
The machine I recently finished building isn’t an Ox, but was built with Openbuilds parts specifically for doing 4th axis work. I’m running TinyG and Chilipeppr, and it works just fine. I haven’t tried CNC Wrapper though. I’m using Vcarve and generating gcode that way. The TinyG post processors for Vcarve don’t support rotary work, but I found that the Mach3 post processors give me code that works just fine – until I have time to hack my own post processor together.
I’d love to add a laser engraver at some point, but haven’t figured that part out yet. Any guidance would be appreciated.
@Jon_Norris that is great to hear! Sounds like we may be able to help each other out here. I’d like to discuss more with you about setting up the 4 axis. I’ll share with you my laser setup 
Awesome! Sounds good.
Feel free to email me directly if it’s easier: jon@jonnorrismusic.com
@Jon_Norris Perfect, will do Jon thanks!
Ok so Jon has a set up a bit different than mine. Thanks though Jon and I appreciate the help you’ve provided. Doing a little digging I read something disappointing. I have TinyG V1 and it only has 4 stepper motor drivers even though it can run “6 axis” kind of misleading. All of my drivers are currently tied up, one for Z one for X and two for Y. I did however read something interesting and wanted to hear what others might think of this. I read about running both of my Y axis Nemas off one stepper driver by flipping the wires on one of them to reverse direction so they are in sync. Now I’m not sure this is a good idea I don’t want to burn up a motor driver by overloading it. However I know the trim pot for the motor drivers is not full power so I’m wondering if by keeping the pots turned down then I may keep the driver cool enough to run both Nemas. This would free up one driver that I could wire for an A axis.
The other option I considered is using toggle switches to turn off X axis and switch on A axis. The only problem is the settings will be slightly different for the A axis so I don’t think that will work with out changing settings every time I use it, not what I want to deal with.
What do you guys think about option 1? Will I burn up the driver running two motors?
Looks like a possible 3rd option could be installing another motor driver into one of the slots above the current motor drivers. These are labeled J17 through J20 in the TinyG. I have a drv8825 pololu driver that looks like it might work. @Brandon_Satterfield you ever try anything like this?
Many people run both y motors off of 1 driver … But it certainly depends on the size of the system.
I think another option is to slave a second tinyg … See https://www.synthetos.com/topics/networked-tinygs-for-5th-and-6th-axis/
@Kevin_Hauser Thanks Kevin, I run Nema 23’s on all axis currently. I have a fairly large OX with approximately 29x36 footprint. I did find a formula for calculating total current to determine if your drivers can handle 2 motors. My hunch is Nema 23’s are pushing that limit. I did also read about networking the TinyG but I am trying to keep my expenses down and go the least complicated route.
I’m really leaning towards using an external driver on the J17 / J18 ports already on the TinyG. What I need to know now is which driver will be compatible. I found a page on Synthetos covering this option in some detail but they don’t give any driver examples to use. Here is a thread where a guy got this working but the driver he mentions I could not locate.
https://www.synthetos.com/topics/tinyg-with-external-drivers-j19-motor3-and-j20-motor-4-dont-work/