Drilling stainless firewall *HELP*

[jamesmil]

ACC has a product just for drilling stainless, it’s called Boelube part # 09-01734

[ykachuro]

What works for me is no cutting oil, centerpunch to create more surface for the drill to bite into, pressure on the drill bit just short of breaking it before the drill starts rotating, then slooooow rotation with the hope of seeing chips starting to come out almost right away. If no chips within a second or two, then I know I am in trouble as the SS at this point is starting to work harden, which makes it much more difficult. And very good backing on the other side. Once the #40 is drilled, updrilling it is a piece of cake in comparison.

[ynkster]

I had same problem, Dan advised that I should use #30 bit. I never had a problem after that!
Bill Mosher, Panther 46

[woolleys]

John, I used #40 cobalt bits from McMaster-Carr in Atlanta. Chucked them up in my air drill, with moderate pressure put a pilot hole in the SS. Then I use a good quality Unibit from Lowes or Home Depot at slow speed to finish the hole. Wobble the Unibit around in the pilot hole and once you get the first step in the Unibit will cut fairly easy.

Just be aware that you will use a few bits and dull the Unibit.

[Jaushnicu]

Hi Everyone,

I am having a hard time getting my firewall match drilled. I am using Avery cobalt #40 drill bits with ""off the shelf"" Home Depot cutting oil. Further, I'm using my cordless drill on very low speed with quite a bit of pressure. After monkeying with this for well over an hour, I have one hole and about 6-7 trashed drill bits https://mechanicguides.com/best-cobalt-drill-bit-sets .

My question for those who have already completed this step.....

Exactly what brand, type of drill bit did you use?
Exactly what type of cutting oil did you use?

Any help on this would be fantastic!

Thanks!