best drills for stainless steel

[TMC]

Hi all

yet another question

will be fitting a stainless steel panel behind a hob need to drill approx 8 x 5mm holes

Are the Heller cobalt drills the best bet and is the cooling fluid better tha using ordinary light oil

Regards

Tony

[Andy Dingley]

This depends on the precise alloy used, however I wouldn't expect a decorative panel that's also presumably quite thin to be a problem.

Yes. You can do it without (most grades of stainless aren't the nightmare that some can be), but these are good. It's worth having a set that you keep for special jobs.

Yes. The main thing though is to use _something_. RTD cutting fluid does just work better - it's thicker and stays put better for one thing. If you're desperate, then I've even been known to use chainsaw oil (also made stickier).

[Jules Richardson]

I've wondered about used engine oil before (I always seem to have some kicking around awiting disposal). It would have "some life left in it" because it's not like it magically stops doing what an oil needs to do at the point where it gets changed for fresh - but perhaps there's a good reason that it's still a bad idea :-)

cheers

Jules

[Andy Dingley]

Well if you _want_ to fling black, used oil around...

[Jules Richardson]

Well, I wouldn't exactly call new oil "clean" - in the sense that it still makes a mess if it gets where you don't want it :-) (although there doesn't ever seem to be much flinging going on at typical metal-drilling speeds)

cheers

J.

[Scott M]

I've got a spray tin of cutting lubricant from Toolstation but I also have an olde-worlde oilcan that I've got (fresh) 10w-40 engine oil in (or whatever I have left over from oil changes on cars.) Both are better than nothing when drilling or turning on the lathe. The oil is stickier so stays put longer and the oilcan makes it easier to apply.

At the OP: for a few small holes in SS I'd just use the HSS ones I've got (and I'm ever looking for an excuse to buy some cobalt ones!)

[TMC]

thanks for the replies have ordered the small heller set

Regards

Tony

[Rick Hughes]

I just drilled a whole load of holes in stainless steel ... ranging from 3mm to 5mm plate, in various diam up to 9mm

Just used standard twist drills with some cutting lubricant .... unless you are planning on hundreds no need to buy special drills.

Usually better to apply more pressure than you normally would, it then cuts cleanly, rather than heating up .... in my case swarf came off as one long spiral, so drill must have been happy enough.

[Dave]

With a 2 fluted drill, on thin metal, you might end up with a triangular hole. Use a scrap piece of mild steel behind the hole, clamped to the SS

Dave

[Dave]

I am in total agreement with what you wrote.

If the drill doesn't bite right away, then you need to get the twist drill sharpened.

Dave

[Jules Richardson]

Well, I tried it out earlier - it works well, but the fumes that aren't particularly pleasant (and probably not very healthy, either). So, perhaps relegated to one of those "in an emergency" situations...

I just bought some the other day, but didn't get a chance to use them until earlier. "like a knife through butter" is probably an apt description - they cut so much better than my HSS bits. Not particularly expensive, either.

cheers

Jules

[Dave Plowman (News)]

AOL. I have a good supply of small drills so junk them when blunt. Larger ones I sharpen. Thus I don't think the cost of a tungsten would be justified - unless doing lots and lots.

[Scott M]

I've found it does smoke but not noticed fumes; you must have got it pretty hot then. Not enough axial force or running too fast?

Right, that's it. I'm getting a set! :-)