Drilling hole in stainless steel

myrns, Jan 3, 4:15pm
I need to drill a 30mm hole is an existing SS sink for a new tap what would be the easiest cheapest way? TIA
tatts2, Jan 3, 5:07pm
what would be the easiest cheapest way? A drill would be a start
rich1969, Jan 3, 5:45pm
And you would need a hole saw which aren't cheap.
franken1, Jan 3, 5:46pm
Did you want to do it in the next week or wait for someones auction to close.
A plumber would use a holesaw.
If you want cheap, grab a Fuller holesaw and arbor from Mitre 10. Around $20-25 all up. Use a lubricant as you cut and do it slowly. The holesaw may be shagged after the hole is cut but the alternative is buying the correct holesaw for 3 times the cost.
I'm assuming you have a drill.
rich1969, Jan 3, 5:46pm
Haha yeah that one would be better
hammer23, Jan 3, 8:23pm
I went to M10 and purchased a 30?mm hole saw to also drill a hole in my sink top for a new tap. I purchased what I thought was a good brand but the thing only scratched the top and gave up so I took it back ,paid a lot more for another and got the job done but I must say I liked the look of the punch shown earlier.
elect70, Jan 3, 9:14pm
Can buy hole punch to fit but arent exactly cheap . . Alternative is to drill series of 1/8 " holes around the perimeter on slowest speed on drill & centre punch them first or it will go all over the place The tap will have a flange to cover the rough edge
daryl14, Jan 3, 9:15pm
Get a group of 10mm holes through it. Followed by steel cutting bit in jigsaw followed by lots of filing. A punch will just put a big dent in the bench.
franken1, Jan 3, 9:54pm
Ain't it easier just to use the right tool for the job?
rich1969, Jan 3, 9:57pm
Think they were talking about a chassis punch, which is the correct tool to put a hole in a s|s bench. It's what a plumber would use.
rbd, Jan 3, 10:55pm
Having done this a week ago I used a decent quality 32mm holesaw from Bunnings. I used engine oil as cutting fluid and kept to a medium speed with a mains powered drill. Mask the top of the bench with a layer of masking tape so the swarf does not scratch.

I used a 1/8 pilot hole, then the drill with the holesaw set, then the holesaw itself. Add plenty of oil as it gets brushed away. It only took a few minutes and no damage to holesaw. If you go too fast you will overheat the holesaw and damage the teeth.

The only issue I had was that when cutting the wood under the stainless layer the holesaw dropped through and the holesaw locking mechanism is an interference fit in the hole I just drilled. 5 minutes to drill the hole, 5 minutes to pound the holesaw out afterwards.
cabrio1, Jan 3, 11:18pm
Cheapest way is to use a 3 mm drill bit and chain drill around the circumference. On the inside of the line. The more accurate you are the less filing you will need to do.
Then use a round or half round 2nd cut file to finish off the job.
Or a drum sander, high speed grinder, depends on what you have.
Common practise in the aircraft industry to make holes.
Bit time consuming, but less than driving to mitre10 and spending money on a cheap holesaw that will be blunt half way through the job. Hehe.
https://80columnmind.wordpress.com/2012/12/31/tutorial-on-chain-drilling/
franken1, Jan 4, 12:21am
My money says your standard 3mm drill bit won't make 2 holes in Stainless Steel. I won't even ask how you get a grinder into a 30mm hole to clean it out.
macman26, Jan 4, 1:02am
I think he is talking about using a die grinder. Can use a grinding wheel or a flap mop.
cabrio1, Jan 4, 1:07am
Correct. I can drill more than 30 holes in stainless with a standard bit. Just need the correct teqnique. Low speed, high torque.
And poster is also correct, a high speed arbor in a pneumatic grinder will work a treat, depending if you have such a tool. As stated in my first post.
A file will work perfectly.
rich1969, Jan 4, 2:23am
I would have thought the aircraft industry would use the correct tools for the job, surely they would have a holesaw or chassis punch kit.
marte, Jan 4, 6:36am
Chassis punch kit.

Or buy a set of stone bits for your drill at the Asian $2 shop for $5 and small drill it out and grind it to shape.

You can use those bits to grind holes in glass bottles too.
cabrio1, Jan 4, 10:45pm
We do use hole saws and chassis punches.
OP asked for the cheapest easiest way, 3mm drill bit couple of bucks, file a few bucks also but possibly may have one hanging around.
With these cheap simple tools, and the correct teqnique this is a 15 minute job.
Probably less time than it takes to get to mitre 10.
And with 30 + years experience cutting holes on all sorts of metal I'm well qualified to argue with you. all day long.

Just out of interest Rich1969 how would you centre a holesaw with an existing large hole? Or drill the correct size pilot for a chassis punch? I know, do you?
Interested to hear your answer, may help the OP should he decide to go that route.
shakespeare6, Jan 5, 12:11pm
Hole saw, blumol brand is all we use. And to answer above if you already have a hole and want to cut it larger with a hole saw, I just get a block of wood and hold it underneath this give the bit something drill into and centre on till the hole saw cuts in.
Been done many many times, very simple.
ryanm2, Jan 6, 12:32am
Go buy either a Lenox, Starret or Blu Mol arbor with pilot drill and a 32 mm hole saw to go with it. Easy peasy. (but you will need a drill).
ryanm2, Jan 6, 12:34am
Also modern arbors have 2 threads for enlarging holes, the inside thread which is higher carries the original hole saw size whilst the larger hole saw sits a few mm below. Also quick / rapid change sets around.
rojill, Jan 7, 3:26am
This is the way to punch that sized hole through the stainless.
kenw1, Jun 17, 5:43pm
A QMax cutter is what is needed.