good metal bits

[Harry Goodwin]

We were having trouble drilling out stainless steel screws in an old warehouse that didn't respond to various screw extractors, drivers and left hand bits. They ate drill bits we currenty had. Anyone with a suggestion of a brand of good stuff. I think carbide would shatter. Harry

[David Keller NC]

Stainless steel is too hard to be drilled with much of anything other than carbide. Back in the day when I worked in a machine shop, that's what we had to use when someone insisted on SS 316 as a material. Even hardened high-speed steel would fold over if shown to SS. Carbide end mills and drill bits will work, but they also don't last all that long with stainless.

Were it my job, I'd be thinking of drilling out the screws by drilling out the wood around them with something like a small hole saw.

[Dave Rose]

Have you tried using cobalt bits and cutting oil?

[harry strasil]

yeah, bits with cobalt in them and a cutting fluid called, tap Magic and slow speed.
The best screw extractors are these. http://www.acehardware.com/product/index.jsp?productId=1290707&cp=&sr=1&kw=screw+extractors&origkw=screw+extractors&pg=1&parentPage=search&searchId=38028925054

so called Easy Outs are actually Hard Outs and should be file thirteened.

[Cliff Rohrabacher]

Stainless steel is too hard to be drilled with much of anything other than carbide. Back in the day when I worked in a machine shop, that's what we had to use when someone insisted on SS 316 as a material. Even hardened high-speed steel would fold over if shown to SS.

Hmmmmm I used to work SST and other exotics like Hastalloy, Monel, HS88, and others making parts for aircraft jet engines. Conventional tooling was mostly what we had. I recall very few carbide tools save for lathe work and I didn't like 'em so much as the carbide we had back then was a tad grainy and wouldn't take a fine edge. So carbide cutting was mostly VIA pressure.

Of course, speed, feed, and coolent were very important. We used a lot of weird coolants like lard oil, 7-11, and some water based coolants.

[John Callahan]

Ditto cobalt and cutting oil recommendation. In a previous life I spent days drilling 318 SS. Even at that plan on going through a few expensive bits.

[harry strasil]

I often had to drill and also use hole saws on SS, I cheated with both by.

1. using the hole saw to drill thru a sponge, left the core inside the hole saw and loaded it with tap magic, as it cuts it self lubricates the hole saw teeth.

2. when using drill bits in SS, same deal a piece of sponge with a fender washer at the drill chuck with a piece of sponge loaded with tap magic over the drill bit, same deal self lubrication.

Note- The clear cutting oil does not work as well as the dark cutting oil. The dark stuff has Lard Oil and sulphur in it for superior cutting action.

[Bruce Page]

You do NOT need carbide to drill stainless steel! I have found that a good industrial quality HSS bit (non Borg) will drill through any of the 300 series stainless from 302 to 321 as long as it is sharp and you are using proper feed & speed. In most cases, quality SS fasteners are of the 300-302 variety and are comparatively soft. I would use the cobalt/M-42 drill bits & end mills when I machined 304L, 316 & 321, mainly because the cobalt/M-42 cutters will hold a sharp edge longer.