Synchronizing Dual Motors (X & A)

Hello.. I have built a CNC which uses dual screw drives for the X axis. I understand that I can control both motors at the same time by setting the pins for the A motor (pins 8 & 9) to "Y Step" and "Y Direction"; however, this will always send identical signals to both motors. That's great if these motors always stay in synchronization. That's not going to happen in the real world. Mach3 allows for separate homing switches for the X and A axes even when the A axis is "slaved" to the X axis. This allows software to individually adjust the relative position of the motors to prevent "racking" of the gantry.

So, my question is whether or not there is a way to accomplish the same thing in LinuxCNC. I can't seem to find a way to do this; however, I am a 'newbie' to the CNC world and possibly overlooking the obvious. I have searched this and other forums and the internet looking for an answer but to no avail. I WANT TO USE LINUXCNC......

I would appreciate some assistance with this dilemma.

Thank You..
Mark

Do a search for gantrykins. Search on this forum and on google for info.

I had planned on getting this set up on my machine, but I found I have no need for it. 2 easy other ways around it.
If your motors are matched to your drivers and machine, and you are not trying to get too much out of them, they arent going to lose sync.

Also, even if it is racked a little, you can adjust the rotation of XY to compensate with 1 line of code.
G10 L2 P0 R1
the number after "R" is the angle of rotation. eg 1degree clockwise in example.
On my machine with rack&pinion, i aligned to endstops square with the gantry.
Before I power up, i run the gantry to the end by hand, then power on.

I meant Y and A .. not X and A.. duh!

Hi

See /usr/share/doc/linuxcnc/examples/sample-configs/gantry for example set up

Run man gantrykins in a terminal for info on how the module works

regards