Drill-capable stainless steel?

I have quite frequently to drill stainless steel parts. And can say what trying, for example, to make ventilated screw from SUS304 standard screw is very low-yield task. Slightest error in feed rate of manually operated drill press, and SUS304 steel hardens, overheats, and destroy drill bit, all in a fraction of second. On the other hand, drilling a standard (iron-carbon-manganese) steel is not a problem at all. But standard steel is not corrosion resistant enough, especially inside the hole where no plating remains.

What i would like is some alloy with good corrosion resistance, but with decent workability. Internet search yielded SUS430 (4016 steel), but i am not sure if it is workable enough for my particular case (manually lowered drill press). Do anybody have some hints on how to drill stainless steel? Or on SUS430 drilling in particular?

It seems counter intuitive but slower RPMs and faster feeds so you can get the material removed before it work hardens. I use high speed steel drill bits.

What warrenb said above ^^^^^^^

Slow speeds (about 60 FPM) and a lot of feed pressure. 135° split point cobalt drill bits are my preference for 304 SS. I drill 100's of parts on 1 drill bit. 5/16, 1.125 deep.

Since I started using cobalt drill bits over standard hss I'm converted.
Everything I drill is with cobalt now.

Another vote for slower rpm and heavier feed with cobalt drills. The key is you must make a chip at all times.

You could try 303 stainless which is usually touted as an easier machining 304. I also think 316 stainless machines easier then then 304 but that's just me.

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Originally Posted by the_gentlegiant

Another vote for slower rpm and heavier feed with cobalt drills. The key is you must make a chip at all times.

You could try 303 stainless which is usually touted as an easier machining 304. I also think 316 stainless machines easier then then 304 but that's just me.

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Yes, i noticed the low speed and larger down-force produce better result of stainless. The downside is what the 1.5mm HSS bit is too easy to break with excessive force. Will try with cobalt drills though.

Use a Screw Machine or Stub Drill as they're called sometimes. Lot less prone to breaking from thrust.

Quote:

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Originally Posted by the_gentlegiant

Use a Screw Machine or Stub Drill as they're called sometimes. Lot less prone to breaking from thrust.

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Searching for "Stub drill" i have found 135-degree drills are made specifically for stainless steel drilling. May be using 118-degree bits was a mistake from very beginning..

https://www.icscuttingtools.com/Screw.htm

Tested finally SUS430 drilling with standard HSS, 2 flute, 118 degrees drills. Can make in average 15 holes 1cm deep each before drill break or become too dull. Seems machinability of SUS430 is good enough even for light-duty drill press.