Slabbing Wizard for Mach4

Maybe someone who uses it regularly would post a quick video demonstrating how they use it. In a nutshell, it’s intended to reduce the effort it requires to make a toolpath that can be used to flatten something. No drawing in VCarve, no models in Fusion - everything done without leaving Mach4.

I’ve made, but not released, another wizard that does the same sort of thing but for holes, counterbores and slots. I made it to simplify spoilboard design. I’m not pursuing it at this time.

I was using the slab wizard today and it does work great and seems easy to set up. I have a question on something I’m not getting right. When I’ve done a run and need to run another round, I had to get the touch plate out and reset my start point every time. When it finished the run, it just stopped at the end of the piece and the next run started there and was air cutting behind the piece. Am I missing something? Sometimes I’m blind to the simple things.

No need to get the touch plate out. If you want to run the same pattern, just lie to the Z-axis DRO (digital read out). After you finish a round, add the next depth you want to the DRO by clicking on it, then entering the new number. Say the run finished and the DRO for Z-axis says 2.000 inch and you want to run another pass 0.020 inch deeper than the last. Click on the Z-axis DRO where it says 2.000 and type 2.020 (2 + .020) then press Enter. Now it thinks it’s higher than it really is and you can simply hit Cycle Start. The next pass will be .020 inch lower than the last. Need to run another? Just keep repeating.

I saw that advise earlier in the conversation of this wizard, but I didn’t get that it would then go back to the original x0y0 position to start over. I’ll give that a try and see what happens. I obviously didn’t listen, I changed the z depth in the wizard itself, not Mach4, and like I said, it did what I asked it to do, but starting where it left off, so completely off the board. Hence, I had to re-zero it. Thanks, I’ll try to follow directions next time! Overall, it does work real slick.

Sorry, I can’t think of a reason your second cut would have started near the end of the first. The wizard doesn’t do anything to affect offsets/coordinates/home positions or anything of the like behind the scenes - it just spits out gcode. One of the first lines in that gcode is G0 X0 Y0 which drives it back to the same G54 work coordinates/datum you had used previously. If the touch plate was used between runs, and a corner was selected instead of just a Z (center button) then that would change your work coordinates, but it sounds like you were just doing Z.

I’m not done with the project yet, I had to delay the finish due to deciding to fill some worm holes and replace some wood rot with epoxy and it is curing as we speak (72-hour kind of epoxy). I’ll experiment some more using my added knowledge and let you know what I figure out.
I appreciate the advice.

Well, it turns out if you follow directions things usually work the way their supposed to! :smile: I was setting up the wizard, running the tool path, then reloading the wizard, changing the depth setting in the wizard and that’s when it would just start where it left off. So I had to touch off between every run.
Turns out, IF I just changed the z DRO setting in Mach4 like you said, it goes back to x0/y0 and runs the pattern just fine! Duh! :grimacing: The only other thing I ran into was when I used the touch plate and set it to the lower left corner, the tool left about 3/16" along the bottom edge untouched, leaving a ridge of material. My work around was to put a spacer between the bottom of the piece and the touch plate to fool it into thinking the bottom was about a 1/4" further down than it really was and everything worked, no matter how many times I added 2 or 3 hundredths.
Thanks, it’s a great time saver.

Hey, alright, thanks for checking it out again. Glad it worked and saves you time - that really was the goal from the beginning.

Similar to the Z DRO number change, you could also do your corner touch off then put 0.188 in the Y DRO…now it’ll travel back that extra 3/16" when the gcode starts running.

But that brings up another question - what tool size and stepover are you using? It shouldn’t miss 3/16" of material - I mean, it could be, but if it does I musta got my maths slightly wrong. Interested to discover if there’s a pattern with this. I’m finishing up the next version to release with added arc linking moves.

Of course, that makes perfect sense. I’ll try that next time. I would assume the same thing would happen with the X DRO to move it completely off the surface on the left. I’d prefer not to slab sideways across the grain. I’d rather move over off the material and come back into it.

BTW: I was using a 2" slab tool with a 1" step over, I believe that was the standard. I did speed it up from the standard 40 to something like 120 ipm, to minimize the burn tracks also.

Got tied up in other projects and forgot all about this one. I added arcs linking the paths back in October but never uploaded it.

Question: Would anyone ever not want to use arcs? Should I make it optional or just bake it in?

Clockwise spiral in

X-axis linear


Hi David, this looks great. Any chance of a metric version?

Hey there Paddy, welcome to the forum!

I’m curious if you’ve tried it. I don’t use metric so my testing might not be satisfactory.

That said, the Gcode it posts includes a G20 code, which will tell Mach4 that the numbers in the program are in Inch and it should do a pretty good job converting. Good enough for flattening a slab I imagine. You’ll still have to enter your work dimensions in Inch, of course.

If you still think that’s not preferable I could add metric to the next release.

Let me know!

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I have not tried it yet, about to update from Mach3 to Mach4 in the next couple of weeks and have just been doing some prep work.

It sounds like it should work so I will give it a go.

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Have you finished the version with the radius arcs? Love this tool, huge time saver.

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Awesome! I know for sure you can install Mach4 right next to Mach3, nothing overlaps. Even if you don’t license it immediately, you can do everything including run short gcode programs.

@Paddy jogged my memory about this and I started working on it again - so the next upload should have arcs and metric option. Maybe this weekend.

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