Weiler E30 Lathe retrofit?

Check the monitor wiring, find where it is connected to the PC/controller and unplug to check the port used, it should be a standard DB15 or DB9, DB9 can not be found but DB15 can be found and even a lot of TFT monitors have them, just a bit older, like 10 years or so.
And just in case it ends up having a composite out (some kind of coaxial cable) or 3 of them in case of coulor monitors, there are still some older monitors with such inputs but harder to find.
Either way, nothing more than 100 Euro.

I have used a Weiler lathe, converted to LinuxCNC. I am not sure what model.
I made some changes to the "carousel" toolchanger HAL component specifically for the Weiler changer. (strobe and parity pins)

You will lose teach-in, I am afraid. But might gain other things (such as my lathe macros

LinuxCNC can be used for re-threading, though it is a little fiddly. I am curious how it is handled in the Sinumerik?

vmihalca wrote:

1. If I keep the current drives and motors and I just replace the controller, I wonder how should I sort out homing for Z. Right now there is a cam mounted on the 1/3 of the bed lenght towards the chuck. The Z axis can pass over that cam and still can travel about 150mm towards the chuck. Can I home an axis in the middle of its travel?

Yes, no problem. In fact that should work with a standard setup, if the switch is closed it will move towards the tailstock until the swith releases, and call that home. If the switch is open it will move towards the chick until the switch closes, then back off. Set HOME_SEARCH_VEL negative and HOME_LATCH_VEL positionve to configure this.

Also the tailstock has a cam for another switch, and if the tailstock is closer to the chuck, it will act like a positive soft limit or smth.

I think that can only be a hard stop, but it's a good feature.

2. If use the lathe in manual mode, I can jog the axes using the mpg handwheels, but if I turn on the spindle, can I do constant surface speed when facing? Is there a way to accelerate the spindle when jogging towards X-?

If you start the spindle from MDI with the constant-surface-speed G-codes then this will work with jogging too.

3. It has a joystick for feeding and rapid traverse on Z and X axes, in manual mode, how could I use those, should I link them to Jog inputs? Also is there a way to accelerate the spindle when jogging towards X-?

Yes, that can be configured to work for jogging, see (2) for SFF comments.

vmihalca wrote:

Regarding homing, I don't think I like the idea of homing against the tailstock switch. I would prefer homing against the middle travel switch. But that would mean jogging the machine before its homed so that I take it close to that switch, then start the homing for Z.
Right now on my mill, I cannot jog when its not homed.

Jogging before homing is a config thing, it can be enabled.

How does the middle-travel switch work? If it is on for half the travel and off for the other half then you don't need to do anything special, the homing sequence will automatically move one way if the switch is on and the other way if it is off. (Set HOME_SEARCH_VELOCITY and HOME_LATCH_VELOCITY with the same sign, and with the sign that makes it move in the correct direction)

Regarding constant surface speed, you mean starting the spindle in MDI then switching back to manual so that I can jog using the handwheels and also take advantage of constant surface speed?

Yes, exactly that. On my lathe I have a turn/push encoder button on the apron that chooses jog increment and switches to manual mode when pressed.

I have been thinking about re-threading and how it could be done.

One way to do it is to start a threading pass and stop the spindle part-way through. You can then move the part in the chuck (either rotate it or slide it) until the tool and thread are in-phase. You can rotate the spindle by hand to check phasing, as shown in this YouTube video: (he starts the threading cycle with the spindle off, synchs and then starts the spindle)

You can adjust the thread phase by moving the starting Z. It feels like something that it should be possible to calculate from thread pitch and a known in-synch position.

If this was a very common operation, then I think that I would consider adding a dummy A-axis and adding the angle of that to the spindle.0.revs pin, so that the phase could be adjusted with a jogwheel. (This would need more thought, though, as A won't jog during a threading pass as the machine is in Auto mode. It might need to be an External Offset.

will linuxcnc just remember the last coordinates then at restart will load those coordinates again?

For this you don't need absolute encoders at all you could just use incremental encoders and save the coordinates at shutdown. I'm not sure what happens if linuxcnc is not properly closed though.

what happens if the screw gets moved while linuxcnc is off?

Absolute encoders require an energy source so they record any motion even if the machine is switched off, mostly in the form of a battery or supercap but there are also models now that can generate their own power. If the power to the encoder is lost the positional data in the encoder is lost as well and the machine has to be homed again.