[scrumper]

3-in-1 is pretty unpleasant, I agree. I use it as a cutting fluid for drilling steel mostly and it's not any nicer when hot. Perhaps I will try some of your gun oil.

Best smelling shop liquid I've yet encountered is Marvel Mystery Oil. It's amazing.

[topspin]

Pluses and minuses as cutting fluid. It's not sulfurized or chlorinated, like actual (and lower cost) cutting fluid. On the other hand, the vapors are non-toxic, being mostly polyalphaolefin synthetic oil, and it likely is better than 3-in-1 as cutting fluid for adhoc use, if only due to significantly lower vapor pressure and higher flash point.