Getting started with diamond drag engraving

Hello everyone!

I’m extremely new to the CNC world and have just purchased a Shapeoko 4 Router along with a 120 degree MC Etcher drag bit for engraving 316L stainless steel watch case backs. I was hoping on getting some information that could help get me started (i.e. feeds, plunge rates, etc.). There didn’t seem to be too much information that was specific to what I am doing so any tips/advice/settings, etc. that any of you could share would be a great help!


Please see:

Thanks for the reply. I notice that you are using the pro version of the software. Is the engraving toolpath not part of the free version? Or would I be better suited looking for different software that can do engraving toolpaths?

While I was using the Pro version, I did not use the Engraving toolpath option which is specific to the Pro version — the instructions above should work w/ the free version — if you have the Pro though, the Engraving toolpath will be much simpler.

The MC Etcher is now included in Carbide Create:

Ah okay, good to know. I noticed that you had the 90 degree bit set up. I got the 120 bit for my engraving purposes and am just wondering if any of the toolpath settings, feeds/speeds, etc. would change based on this. Would I be okay to copy what you had for my 120 degree bit?

Should I also change anything based on the fact that I’ll be engraving text onto 316 stainless steel?


For the tougher material, I believe you’ll want to use the more acute V endmill.

Prior to purchasing my CNC, I consulted with Carbide regarding my exact plan of use, and was recommended the 120 degree tip and assured that this would be fine for engraving 316L stainless watch case backs. Are you suggesting that the diamond drag bit wont be effective for drag engraving 316L stainless?

My comment was based on the note on the shop page:

The 90-degree tip has better penetration in very hard or anodized materials.

I might be missing something, but it seems to me that using the MC Etcher is not possible on the Nomad without upgrading to CC Pro.

The reason is that MC Etcher RPM setting of zero RPM is rejected with a little message saying that RPM must be between 1 and 100000.

What happens on Nomad 3 if I override the settings and ask it for an RPM of 1?

It does seem to be a silly range limit anyway. An RPM of 1, or even 60 would be a great way to distribute the wear around the diamond tip without causing any real heating, but I don’t imagine the spindle is up to it.

At this time, one has to manually edit the G-code to remove the spindle on command.

Ah ha! Thanks. I’ve seen that somewhere.

Edit: see Winston’s post at: Drag Engraving w/ the Spindle Off on the Nomad CNC - YouTube


Winston says to look for something like “Snnnn M3”
AFAIK the Spindle Speed control in Carbide Motion’s custom G-Code looks like “M03Snnn”
I “removed” that instruction by enclosing it in brackets, turning it into a comment. When I try to run the modified code, CM freezes at what I think is the step that I’ve just “removed”.

This fiddling is beyond my current comfort zone. :slightly_smiling_face:

Edit 3:
I can’t replicate the previous freeze so I suspect some other fat fingered problem was in play. Instead, simply overriding the zero RPM in CC with 1 will get gcode written. Commenting out the line “M03S1” stops the spindle and the engrave bit gets dragged along the contour profile.

Yes, it’s primitive that you can’t enter zero. The work-around:

Open the saved .nc file in a text editor, I use TextEdit on Mac. Search the file for “M03Sxxxx” where the xxxx is whatever speed you set in CC. Delete that line.If you have multiple engraving tool paths, you will need to do this for each path.

I usually set the speed to 327, the displacement of my dad’s Impala SS I took to the prom 60 years ago, so I can more easily identify the lines of code. The process is a slight bother, simple unless you forget to do it.

I just have use S327 from now on too !!

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