Synchronize 2 axes in manual mode

It is possible to move 2 axes at the same time (synchronized) in manual mode by means of a joystick, the idea is to move the X axis and the A axis to position parts with helix. Enter the pitch of the helix in some text box and with the joystick or a button move the X axis and the A axis according to the pitch of the helix.

Should be possible in hal, basically a custom jogging mode...

I think that one of the ways could be switching the kinematics.
linuxcnc.org/docs/2.9/html/motion/switchkins.html
Normal kinematics:
A = A
Thread kinematics:
A = constant * Z

I am by no means a kinematics specialist.

Any example of how to perform a custom jogging mode?

Do you have normal joystick jogging set up?

That would be the first step.

Basically you would feed the jog count generated by the joystick component
to both A and Z jog count pins (axis.a.jog-counts and axis.z.jog-counts)
with a predefined jog scale for A and Z (axis.a.jog-scale and axis.z.jog-scale)

You would also have to set axis.a.jog-enable and axis.z.jog-enable
Ultimately you would like need some logic and perhaps multiplexer
components to allow selection of this specific mode while allowing the normal
per axis jog modes to still operate normally

I have been very busy all month and I have not been able to resume the issue.
The joystick is connected to:
# --- JOG-X-POS ---
Net Jog-X-Pos <= Hm2_5i25.0.7i76.0.0.input-20

# --- Jog-X-Neg ---
Net Jog-X-Neg <= Hm2_5i25.0.7i76.0.0.input-21

How can I connect the joystick to the axis.x.jog-counts?
In the manual:
axis.l.jog-counts in S32

Connect to The "Counts" Pin of an External Encoder to use Physical Jog Wheel.