The history of wheel engraving on glass goes back many centuries, back to Ancient Rome and very probably beyond.
The basics have changed very little over the years. The basis is that a hard material can be cut/ground or drilled by using a soft material as a guide (in this case copper) plus a hard abrasive and oil. I believe the traditional oil was Colza oil which is made from cabbages. It does smell, I can vouch for that as we used it at ECA!. Now a days I use olive oil.
Unusually it’s the glass that is moved not the tool and to do that the engraver rests his/her elbows on two pads. The lathe is a very simple tool, really only a shaft with a tapered hollow end where the tools are inserted. The copper wheels can be bought ready-made but many engravers make their own. My own lathe is a traditional pattern but more modern lathes designed for diamond wheels are available. KMK in Germany make a portable version. Diamond probably cut faster and certainly they need only a drip of water to cool and lubricate the process.
Copper wheels need to have the mixture of oil and abrasive applied frequently. There is, however, a beautiful “feel” about engraving with copper wheels, not unlike painting with a high quality sable brush.
Touch is so important in wheel engraving; for a start most of the time it is difficult to see what you are doing. The abrasive mixture obscures everything and the glass is held behind the wheel not on top of it. It feels awkward at first but it gives a great deal of control.
Wheel engraving requires a bold approach as a diffident touch is all too apparent in the finished piece. Mrs Turner described the process as “a dancing gesture” and rhythm plays a big part in good engraving. Every touch of the engraver is recorded for ever.