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drilling stainless!!/ melting drill bit

I decided to drill a 5/16" hole in the end of a 5/8" piece of round stock (SS 404 i think).... it all started well , I was going at a relatively slow pace . the chips off the drill bit looked ok after i got 1/4" in i got a little smoke but i didnt think too much about it.. but the rate of drilling slowed down a bit. THEN i looked down and the drill bit was GLOWING BRIGHTLY! it melted!!! I expected stainless to be a bit tougher than regular steel but not like this! what did i do wrong? rtv

Reply to
rtv
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Reply to
JR North

i'm sorry i think i meant 304 stainless rtv

Reply to
rtv

On Tue, 09 Dec 2003 20:03:01 -0500, rtv put forth the notion that...

Gotta go slow with stainless. The hotter it gets, the tougher it gets to cut. It'll burn up HSS tooling pretty easily, even when the work piece gets red hot.

Reply to
Checkmate

I've been told some grades of SS work harden significantly if the drill dwells in the hole, forming an hardened button that can deflect the drill off axis. I have not experienced it firsthand, but the same source tells me the solution is to use drills that can take the heat and apply steady feed (if pauses are necessary, remove feed pressure completely to keep the drill tip from working the material).

StaticsJason

Reply to
Statics

--Whatcha using for a lubricant?

Reply to
steamer

Internet and trade shows only. Phil

Reply to
Phil Ordway

Slow and a small drill first.

Larger drills don't drill a center - it spins in the metal. The cutting force isn't high at the center with the radius short.

Work up through drills.

Might have to use carbide to drill a pilot now. May have to heat treat to relax it.

Martin

Reply to
Eastburn

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