Charles Courtneys books, Volume I & II

[chubbbramah]

Diamond-pointed drills are today commonly used for drilling glass and [glazed] ceramics. They are preferably lubricated with liquid paraffin.

[4xlock]

A bit of time later I've tracked down one newspaper clipping from a much bigger article on tools of the trade for burglars. This is from 1893 Feb 16 newspaper article. I don't believe this is referring to the tip geometry. I have an add also 1892 for "the diamond drill is pointed with black diamonds". Also on an English criminal, in the US, who used diamond tipped drills for his work, caught around 1890. Somewhere there is a much older newspaper article if I can find it. It's a good number of years since I read it but I'm positive it was 1860's. I've never seen catalogues with these in for this time BUT newspaper articles pop up with these oddball things. It's quite clear that this was a well established technique. For a safe & vault opening job they'd use state of the art techniques developed through practical experience.

[4xlock]

Cutting

[Huw Eastwood]

A bit of time later I've tracked down one newspaper clipping from a much bigger article on tools of the trade for burglars. This is from 1893 Feb 16 newspaper article. I don't believe this is referring to the tip geometry

During this period the term was commonly used for the type of drill with the geometry clarified previously, the 1893 newspaper article you’ve added is another example of reference to same, and, again without any clarification that the drill was actually ‘tipped with diamonds’, ‘studded with’, or the tip or point being ‘embedded with diamonds’...

I have an add also 1892 for "the diamond drill is pointed with black diamonds"

What happened to the rest of the 1892 advert from which that extract was taken ? Especially since it would be the smoking gun that quoted that the drills were actually ‘pointed with black diamonds’ ?
Shame that, do post the rest of it up here, presumably you have it in order to have extracted that line from it ?

Also on an English criminal, in the US, who used diamond tipped drills for his work, caught around 1890. Somewhere there is a much older newspaper article if I can find it

References like this to diamond tipped drills unfortunately don’t confirm anything different that we already know, so do post up all of the adverts, brochures etc where you’ve seen them whenever you find them. Hopefully they will be more specific and actually confirm that the drill points or tips had diamonds actually physically set within them.

FWIW, The techniques of the day are not under question, nor are the fact that they would have been built on practical experience like you stated. When you say it’s clear that it was a well established technique I’m sure it probably was, but that is with the known and commonly referenced diamond point drills of the day, until of course, we find evidence to confirm otherwise.