Drill dimple issue

No worries Keith.

Did you ever try out the idea of having a mechanical probe offset from the torch?
 

Nah Phill, I got sidetracked with multiple other things - rope access techniques (and I'm shit scared of heights), fishing, then got a fishing boat, ice skating, family, etc.
My workshop got into a very neglected and disorganised state as a result, and I'm now trying to mend my ways and get back into CNC, etc.

Fair enough, life does tend to get in the way sometimes.  

If you do get around to it the basics are now built-in.
linuxcnc.org/docs/devel/html/plasma/qtpl...ml#qt_offset_probing
 

Phill, what are you doing to me. I'm supposed to be getting ready for an ice skating session but now I'm all excited to read about that 

Seriously that's fantastic news, appreciated.

Just had a quick read. So let's say if I have a stiff bent wire probe that is mechanically moved directly under the torch, the torch will have to be higher up to allow that, and thus I've got a Z-offset.

If I've got this right this "Z offset" is the:
Ohmic Offset in the PROBING frame of the CONFIGURATION section of the PARAMETERS Tab

Is that correct ?

Correct, if you use the ohmic input as the input for this probe.

Theoretically you could use the float input for this probe but I think it is always best to keep the float as a failsafe.
 

Cheers Phill, Qtplasmac just keeps getting better.

I gotta ask. How much time do you think you've put into Qtplasmac/Plasmac since you started it.

I have not kept track but it has been my "job" since I retired. 

Edit: I should add that Greg (snowgoer540) has a lot of time in it as well.

Plasma cutters use timers, most of them using an R/C timer that is not precise. That makes getting consistent dimples very hard.
Some stuff that helps avoiding "craters" as Phill so nicely said, is to lewer the air pressure as low as it can go without missfiring, setting the pierce height as high as it can go without missfiring, doing some test to see how long it takes from when the torch is on till it fires with and without air fllow, using low current, using bigger sized nozzles, using new nozzles and electrodes as the black stuff on them messes the arc start.

phillc54 wrote:

I have not kept track but it has been my "job" since I retired. 

Ah OK, so there's two heroes. Fantastic work guys.

A few years ago I got a kidney stone and I was off work for 5 weeks. I made a heap of progress designing/programming my torch height control in that time. I could literally go all day long writing/debugging code (takes longer when you're a beginner), testing physical signals, etc. It was a journey I enjoyed.
Since working a 9-5 I make very little progress with such stuff, and I always think how wonderful it would be to be retired so I had the time for such things. Hard to get into that "Zen" state when you only have an hour or two here and there, and you are knackered after work.