[stovepipesteve]

302 stainless steel.Running VF3 mill
im drilling holes thru a web.i ve tried standard drills,adjusting speeds and feeds for stainless.*
What happens>* the drills do not last long. As they dull, it starts to bend the first wall i drill thru(which is about .25),then it rapids down to the second wall, by then the drill is walking. This aint gonna fly.
Ive purchased 1/2''colbalt TiN coated drills and 3/8 TiN coated drills to work the holes. i have yet to try them.Does that sound like what i need? What speeds and feeds to start? I also need to drill a .090 hole and a #20 hole. The .090 hole is given me fits also.*any suggestions that might produce would greatfull.

[PBMW]

You haven't told us a thing about your speeds and feeds....
Machinery's tells us to drill (HSS) at 20 to 40sfm. With your half inch drill that would be 153 to 305 rpm. feed is .007 to .015 per rev.
Your .09 drill ought to go 1273 rpm and feed about .007.
302 will work harden so I would not peck it. If I had a choice, I'd be using something like Moly Dee on it.
You may have to split up this op into two drill ops one from the opposite side ...
Sucks but that's why we get the big bux...

[HuFlungDung]

If it is something that you cannot index to drill from either side, perhaps drill undersize, then correct the hole position by redrilling (at a careful feedrate) with a long endmill with the correct diameter. Carbide tooling is stiffer and may resist walking better.

[automizer]

You may want to look at Drill point endmills, far less likely to walk away on you.