A tool rep from Sandvik stopped by the shop in Wichita three weeks ago and asked why I was cutting 4140 dry on the face mill, said I was leaving insert life on the table. I ran the same part both ways and got 40 more minutes of edge life with a light air blast, which stung a little. Any of you running air blast on manual mills, or is it more hassle than it is worth?
40 extra minutes just from a light air blast? That's wild to me, I would've bet money dry was close enough on 4140. I ran dry for years on a manual mill mostly out of laziness, but that kind of gain is hard to argue with. Guess the rep earned his paycheck that day.