I thought that I had given the old simple measurement when it all could have been done on a Columbus gauge, See Spaparey's the Amaturs Lathe book.
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After looking at a video by a crtain 'ClickSpring', I realised just how different my fumblong description was in comparison.
Sparey (and I) were creating a a flat surface whereas Clixkspring was creating what was/is an engraving cutter.
Again, George H Thomas writing in Model Engineers Workshop Manual ( and in his section on boring tools) shows some tools similar to that of Leaonard Sparey.
I suppose that it is a matter of choice. Neither is wrong.
What is interesting is that old Sparey has also modified an ordinary twist drill to create a flat bottomed surface.
It's all a BIG topic and hearking back to the humble homemade Quorn , it is possible to cut a hss or high carbon steel tool on it whereas the Deckel SO and its clone was actually designed specifically for a multitude of engraving citters in the engraving business.
However, using the method which I described will , if the large flat is ground FIRST does not need to use the azimuth rings for that operation.
However, I shudder to think that the front of the cuttingnose grinding PRECEDES the much simpler and larger ;flat!
Maybe you might mentiom in more detail your intentions
But I hope that this helps somewhat
Norman