Im always bumping the machine off of my X Y mark while changing bits and its a crap shoot trying to get it back on point. I got thinking (which is kind of dangerous). I got a piece of rigid aluminum, a 4mm cap head screw, a wire holder, a can of black paint, and a laser pen. Once set up you can set Zero and mark where the laser pen hits your waste board or your corner piece you set up on top of the waste board.
Zed.pdf (102.8 KB)
I understand the frustration.
Locking as John suggest is one thing everyone should do regardless of having issues or not 
However - if you have homing switches installed, and do a homing sequence prior to setting your work-zero, you have already a persistent reference point.
My workflow:
Well Ill tell you I did not know you could do that. Thanks for the reply.
The problem with homing is I have a corner jig set up so my homing is offset. I understand your solution but in my case it will not work. Some day I’m going to install T tracking and eliminate a lot of my issues. Thanks all for your comments, they are very much appreciated.
Do you mean homing is offset aka work zero is offset relative to Machine Home/Zero?
Work zero is persistently stored as an offset value relative to Machine Home, so if the machine is homed (Machine zero) the work zero position is persistent and can be consistent for your corner jig.
One could also use G28/G30 so provide additional two persistent parking spots so you could in fact have two individual corner jigs / fixtures and quickly alternate between the two as seen fit.
The prerequisite is homing the machine prior.
I have used the G28/30 function in the “designs by Phil” webpage to set my xy when carving a project but is there a way to set that permanently as I have a corner block set up and when the machine is powered down by emergency switch or otherwise it seems to lose the G28 location.
G28/G30 functions require that your machine is first homed using grbl’s homing function ($H) in order to save their set positions upon powering down and back up. I.E. homing is required every time your machine is powered up.
Work zero and G28/G30 coordinates are all stored as an offset value relative to Machine zero / Homing
So if you home the machine ($H) then jog to your intended work zero / G28/G30 positions before assigning those, these positions are persistently stored, relative to machine zero. They do not change unless you re-assign a new position.
Thanks this is exactly what I was looking to find.
