HSS Engraving Cutters

Hi Nitromethane,

Again many thanks. Evidently running feed rate far to high and thanks for the compressed air/mist suggestion. I understand what else I was doing wrong re the hardened chips.

Regarding this mist coolant idea (which I could use on my desktop lathe/milling machine as well) - has anybody tried to make a DIY mist coolant spray unit using a car's 12v tyre inflator unit plus some form of pitot tube vacuum supply of coolant solution. The tyre inflator unit would be quite capable of supplying the required air flow through a small nozzle (after all it has to push 40 psi and a reasonable volume through the tyre valve) and a small bottle of coolant with a hypodermic tube at right angles into the air flow tube close to the exit would provide the mist. Just thinking off the top of my head although many years ago I did make something like this to measure windspeed through a tube - the vacuum at the hypodermic tube end was used to "pull" a column of oil up a calibrated tube.