[WATERJET71]

Hi,


I need some help what kind od drill bit a need to drill .039 (1mm dia) on 304 sst is it even possible or do I need to make a fixture jig (bushing jig).

I have a Haas mini mill can i get done or not?

Thank you

[fizzissist]

piece of cake.

Split point, 135deg, screw machine drills, 90deg spot drill for starters, and flood coolant. Peck if you're going beyond 2 diameters, and make sure that when the drill comes down for the subsequent pass it starts feeding just above where it left off, in case there's any chips left in the hole.,,,, Usually isn't because the stuff is stringy.

I know what the numbers say, but I'd start it in the neighborhood of 4000rpm, and feed at about .001-.0015/rev feed. I've run a lot of .013 holes at that rate with success in 304L.

[wizard]

piece of cake.

Split point, 135deg, screw machine drills, 90deg spot drill for starters, and flood coolant. Peck if you're going beyond 2 diameters, and make sure that when the drill comes down for the subsequent pass it starts feeding just above where it left off, in case there's any chips left in the hole.,,,, Usually isn't because the stuff is stringy.

I know what the numbers say, but I'd start it in the neighborhood of 4000rpm, and feed at about .001-.0015/rev feed. I've run a lot of .013 holes at that rate with success in 304L.

The problem is the need to break through any work hardening that will be there after the peck cycle. There are so many stainless drilling theories out there that I don't know whom to believe anymore.

One thing that I do know is important is to use good quality drill bits. You hinted to this above but if the original poster has many holes to drill they should consider talking to their tool supplier to come up with the best options.

[fizzissist]

Work hardening comes from rubbing the tool against the work.... and if your machine retracts the drill efficiently, that won't happen. You cut, and get out, then get back in without ever dwelling. Dwelling is another spelling of death for tools.

It's a nightmare with something like A286, but not 304.

In any case, when deep hole drilling with a conventional twist drill, you're forced to peck when you get past so many multiples of dia for the chips to clear.

Looking back at my earlier post, I'd back the feed off a little for that dia., to around .0008-.0012/rev.