Tips on drilling stainless steel ?

[ferguscawley]

Guys

Am not a fitter by trade so need some of the expert help available here...

Is there a special type of drill-bit needed to drill through stainless ? I had difficulty drilling through 1mm stainless plate last night with a regular metal bit.
Is there a trick or two to do this cleanly without the metal becoming red-hot ?

Any help would be much appreciated. ta

Ferg

 

[Fanum]

Stainless will blunt a drill bit very quickly....so if you're attempting it with a used bit, you're likely to have a hard time ad it'll rapidly start having no effect.

I drill into zinc coated steel panels most days..i tried using some expensive bits and they worked and stayed sharper a bit longer but i've reverted to new cheapo metal bits and chuck them away regualrly....it actually works out cheaper.

If your drill is variable speed, try slowing it down........this helps a lot and is actually essential for using things like hole cutters or cone drills.....

Best tip i can give you is use a small drill ( 2mm maybe) to drill a pilot hole then go to a 6-8 mil drill, then up to whatever......and with the small sizes you can go to high speed without too much problem as well.

Roll on the experts..............................................................

 

[Steptoe]

Might be stating the obvious, keep the speed slow, keep it lubricated, if the metal your drilling gets red hot you'll be hardening it, just what you don't want --

 

[Frank Warner]

Stainless is fun stuff...

For most machining jobs slowing the cutting speed does no harm .. just makes the job longer. And that is a safer option for us amatures. If a work piece is heating up then so is your cutting edge... and that will take the temper out of the cutting implement .. meaning it will get softer and blunter that much quicker.. if it has got too hot then you may as well throw it away... or at least when sharpening it take the first 1/8 inch off the edge before starting to sharpen it.

However for stainless you actuall are better off at the right speed.
And you really need a sharp cutting edge. Buy your self a new bit (or 3) .. for 1 mm thick you need to back the material so it does not deform as you drill it.. use some scrap mild steel.

 

[Rob Farmer]

Once you start drilling don't stop or back off the pressure. The material will harden so you need to keep going. A sharp drill bit and the right pressure/feedrate is essential.

 

[blumeeni]

I think your supposed to use a different cutting angle on the bit I dunno what it is but I'm sure there's someone on here that does blu

 

[(RIP) Mark Dilloway]

Drill a pilot hole first then go to the size you really need. Just look at the end of a 5- 10 mm drill bit - the point will have no cutting edge hence no progress.

The same applies for drilling holes in plastic number plates.

 

[MiGSel]

I have heard that you need cobalt drill bits for trouble free SS drilling.

Haven't tried it yet, because I wouldn't know where to find 'm. Not that I've been looking very hard yet either.

Cheers,
Michel

 

[(RIP) Kaister]

we make lots of stainless stuff here .

Use a new drill for starters.
If yours got hot - its blunt - end of story - throw it away or break it in half and re-sharpen a point on it.

You can get Ti coated srills - they're the biz - but pricey

What size hole into 1mm sheet ?

Anything bigger than about 6mm and the drill will catch due to the cutting angle of the drill. - use pilot drills and good quality cutting oils

If its a large hole - bigger than 10mm - use a hole saw - starrettt yellow - see RS for quick tools

Phil

 

[Vern]

Forget the cutting angle of your normal drills, for sheet metal, you won't drill a round hole in a month of sundays with a drill like that. Re sharpen them all, into trepanning cut edges, then you don't need to pilot at all, just bang whatever size you want straight through, nice round hole every time. Easy innit

 

[ferguscawley]

Thanks

Thanks for all the info.
Just one more thing, is there any merit in using these titanium coated drill bits you see advertised everywhere - or are they just a marketing gimmick ?

Ferg

 

[MiGSel]

Re sharpen them all, into trepanning cut edges, ...
...Easy innit

Can you err... illustrate that a bit Vern?

 

[Padge]

Re: Thanks

Thanks for all the info.
Just one more thing, is there any merit in using these titanium coated drill bits you see advertised everywhere - or are they just a marketing gimmick ?

Ferg

Ferg, They're overpriced sh1te. 90% marketing gimmick.
Knowing where you work, would you not ask one of the fitters there to do it for you.
They use a lot of Hastelloy parts, especially C22 which makes SS feel soft as butter.

 

[PeterNicholson]

A trick I picked up somewhere...

If you can get the drill vertical: make a circular dam up around the hole site with BluTack or similar, and fill it with cutting oil. This keeps the drill tip immersed in cutting fluid. Also, keep the drilling speed down and the pressure on.

Regards

P

 

[GSPeP]

I have heard that you need cobalt drill bits for trouble free SS drilling.

Haven't tried it yet, because I wouldn't know where to find 'm. Not that I've been looking very hard yet either.

Cheers,
Michel

Cobalt drills are the best for SS. I've tried them and it's a big difference compared to the standard HSS drills.

A 6 mm. hole in 10 mm thick stainles steel took three and a half minutes with a brand new HSS drill, which you could throw away afterwards. The same hole with a cobalt drill took only 45 seconds, and the drill looked as if it never had been used before.

 

[MiGSel]

Hi Peter,

Can you remember where you got the drills from?

Cheers,
Michel

 

[Padge]

.. http://www.wntuk.com/ ..

Usually have good discounts.. ie. 6mm Solid Carbide drill for £6.40

 

[Vern]

Here you go, one trepanning drill, the only way to drill round holes in sheet metal