Disappointing start to etching glass with drag engraving

Started to etch a 4mm thick piece of float glass today. Using a 60 degree diamond etching drag engraver as sold by RDZ.

Used the engraving toolpath and set it to .1 pass depth and .1 engraving depth. Worked for about ten minutes and then no diamond was present. Frustrating.

That can happen, did You check the glass for surface defects beforehand?
I prefer to use lubricant/coolant for diamond drag engraving, because the bonding and diamond can overheat causing failures.

What was you feeds set to?


When you scribe glass for breaking into smaller pieces you use lubricant on your glass cutting wheel. So do you just smear oil on your glass in the area you are going to engrave? It makes sense. The diamond is very strong but the bonding to the stem is always the weak point. I turn on my lathes and have a Wolverine Sharpening Jig and one of the tools is a diamond dresser for the wheel. The Wolverine instructions tell you to carefully come in contact with the wheel to avoid knocking the diamond point off the surfacer…


When I am using my DDE on granite, I use a mild dish detergent / water solution and it works fine. A light oil may work as well, I just wanted to avoid the oil, because it changed the color of the engraving on the stone (in a bad way) and it is easier to use a soap / water solution than to have to use a heavy soap water solution to get the oil out of the engraved stone after the fact.


Yes. It was good quality float glass that was 4mm thick… without any surface defects.

hmmm… this was one probable cause then. No coolant or lubricant was used.

I set a feed rate of 400mm per minute (15.7") I had thought that would be a good starting point.

Thanks for your input, Andreas. It is very much appreciated. I will order some more glass, another engraver (or two) and some cooling oil.

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Yes, I understand that… now, Guy. I had no thoughts about lubrication of the diamond and the glass. I thought that 0.1mm (just shy of 4 thou) would not be too tough on the diamond. My maximum depth was also 0.1 and I had found the zero point very carefully and then added 0.002" from zero, to lightly compress the sprung part of the bit.

Thanks for the idea. It sounds very easy and very workable. I will try that next.

What does this mean? The Diamond was missing? (That’s how it reads). I’m a little confused

PS I use and like WD40 for my diamond engraving.

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The manufacturer lists 20ipm so You should be safe.

Also fast plunging onto the glass can also crack a diamond.

I have used kerosene, light mineral oil or soap+water on plain glass.

Also a tip is never run the diamond engraver off the edge of the glass, it is tempting to use it to brake down a larger pane into smaller pieces, just don’t.
Stop close to the edge and score out to the edge by hand.


Apologies, Richard. I started engraving with the diamond point in situ and then it was no longer there and engraving was not possible. Looking at possible causes, it appears that lack of lubrication may well have presaged the event. I have a lot of WD 40 on hand so will try that when I next attempt to engrave glass. Thanks for your input.

Yep, I had thought the speed of the feed was ok. It did not appear to be placing undue stress on the tool or the glass. I had pretty much no plunge speed at all and only from a height of 1mm. Less than 4ipm was my chosen plunge speed.

I now see that the take home here was that I should have used some lubricant. I had ensured that the pattern I was engraving was 10mm inside the edge of the glass so no falling off the edge when engraving and I had set a retract height of 1mm.

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Kero works great (as well as WD40)…but wow did it stink up my shop…unlike WD40…which is…well…a photo is worth a 1000 words:

Screen Shot 2021-07-09 at 10.57.25 AM


Ahhh, I was using bio-kero, does not smell like the fossil kero.

When engraving plastic is lubricant required, or is that soft enough to not require it? Starting some plexi engraving in the near future.

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Hey we all have to learn. Will you try to get the tool warrantied, I would. Sounds like you did everything right. Maybe the diamond was never bonded well.

I learned from this post to use soap and/or lube. I think it was MadHatter who suggested the soap for granite/stone so you dont pollute the stone. Granite for kitchen counters get ugly with grease where manmade surfaces dont seem to mind grease.

This forum is a great source for learning. I got the two mcetcher bit but have not used them yet. Good info.

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I may try that, Guy. I note that RDZ do supply replacement tool inners. I have not had much luck with trying to find out how to change the centre. This means a contact message is in my inmmediate future to see what, if anything can be done. Some spare tools are also in my future. The MC Etcher set is out of stock for now and no suppliers outside of the USA are showing them at all.

There was a shipping error with the MC Etchers I received for the magnet competition - they sent two sets by mistake. I’ve offered to return one set, but was instructed to keep it.

I’m happy to pop one of the spares (90 or 120 degree) in the post to you gratis, @Jepho. Just PM me your address if you are interested.


Only one heart possible here, Gerry.
What a generous and very welcome offer. (accepted!)
PM sent with alacrity. :grin:

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Update to my stupidity:
I contacted the RDZ company via a web contact form and explained how I had broken their well constructed tool. The company advised me about their replacement inner core and I now understand that the holding hex screw can sometimes be a little tight to move.

They will sell me a new inner and are adding a replacement core gratis. They have also offered to find the cheapest shipping option too. Incredibly helpful, kindness beyond necessity and great customer service. So here is my shout out to RDZ…

If MC Etcher is out of stock, give these people a try (if you are in the USA) because they went the extra 10 miles for me. Thank you for the suggestion to explore the warranty, @gdon_2003. It was an excellent suggestion, Guy.


No lubricant needed for acrylic or plexi.