Possible to run a 'test job' just above the surface?

Hi. If I’m trying to double check a tool path…what would be the easiest way to check this without cutting into the material? Do I just set the z height a little higher so it effectively doesn’t go down onto the wood?


Hi @Mavoz!

Yes, you can do exactly that - set your zero far enough above your work that it is just out in space - just make sure that the height above your work is far enough that when it does plunge, your work isn’t contacted.

That said - be warned - I did exactly this but wasn’t careful, and immediately drove my bit into the work when I wasn’t expecting it.

You could also try setting everything up as if you are going to run (including the Z) but then remove the router bit - which would give you at least one inch of clearance, and you won’t have to worry about it.

Hope that helps.


Thanks for this! I wonder if this could even be a GSender feature. I love the outline mode as it has already saved me . But also one that automatically runs one lap 5mm above z would be awesome too But thanks for those tips… can make that work… just have to test the workflow. Thanks!

I swear to you that I have “cut” a piece by raising Z-zero slightly, clamping a 1/4" diameter strip of eraser (yes, I too make mistakes :smiley: ) and running the job.

It was a small job, I was new to CNC and I found out that my clamp would be slightly trimmed. (Later on, I just trimmed those clamps and moved on! :smiley: )

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I have come to realize that I make fewer mistakes going all-in on setting things up correctly (including Z) - so removing the tool (or clamping in a chunk of eraser) would be much safer for me!

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Thanks All. Well I had good success with the testing method! Appreciate the tips!

I’d had a bit break on me half way through this cut for an outside bench arm rest…and so had to totally reset the path from scratch (with a 6.4mm bit instead of a 6mm)

I set the bit 5mm up with the Z height…used “Go to Z height” feature to check z height is indeed safely above…then started the ‘fake job’…with my hand on the “Stop” button (using a keyboard shortcut ready to slam it to a stop before it would hit the wood)

I then found I could see exactly where the cut was going to go…with the bit hovering around the previously cut wood 5 mm up…and made tiny adjustments to the x and y so the path was as close to spot on as possible…I then launched the real job…

This all worked brilliantly as the cut was nearly identifical to the original pass…

So highly recommend this method…just make sure you have a “stop” shortcut key ready like X before any carnage can ensue! Thanks!