Drilling stainless steel

[TNhobbyfarmer]

I will be starting a project in a few weeks that will require me to drill stainless steel. Couple of questions; will I need any specialized drill bits? What is the best liquid lubricant to spray during the process? I remember seeing one recommended by several on TBN but can't remember the name. Thanks for any and all advice.

 

[Industrial Toys]

I did some stainless work. All stainless is different. I used a special cutting fluid for stainless. Guys here can tell you what speeds and so forth.

I ruined a nice 6" Bimetal hole saw almost immediately trying it on SS, even with the cutting fluid.

 

[mrmikey]

will I need any specialized drill bits

No, good quality but not necessarily specialized unless you're doing a large amount, sharpened at a bit pointier angle. Carbide would be better if you're doing a lot but easier to ruin.

What is the best liquid lubricant to spray during the process?

I've used water based, oil based and had better luck with oil. Sulpher based is recommended but I never noticed any difference. Make sure your either keep it flooded or dry, one or the other, constant heating and cooling will harden the ss and ruin the bitt.
Don't let the drill bit bear without cutting, it'll surface harden the ss and then you're SOL. if the bitt's touching the steel, it should be drilling Go slower rpm wise than what you would comparable mild steel. Some older machinists had even gone so far as to state to use a three cornered centerpunch so you don't spot harden the surface with a conventional round centerpunch........Mike

 

[Industrial Toys]

The heating and cooling is very interesting. I never heard that and certainly didn't think about it. Always meant to get a magnet mount air nozzle. Good idea or not?

 

[Oldpath05]

If I was drilling SS, I'd get cobalt............... https://www.amazon.com/Cobalt-M42-D...t&qid=1561155036&s=gateway&sr=8-1-spons&psc=1

 

[dstig1]

Drilled a lot of 304 SS for my railings the past year and more to go this year. It is far easier to do in a drill press or mill than by hand. You need to apply significant pressure to do it, and that is just plain hard to do by hand as you often don't have the leverage. Regular HSS works fine, and I have been using Tapmagic oil which seems to work Ok also. The point about not letting the bit spin without cutting is good, and one of the difficulties with hand drilling. I bought a bunch of bits from Mcmaster in the short length to allow more pressure without deflecting them so much. They had a price break at like 12 bits, so i did that. I think i am still on my first or maybe second after a few dozen holes.

 

[spitter]

Working in a food plant that's all we do drill SS . When you have to hand drill Like Mrmicky said good sharp bit lubricant slow speed lots of pressure . If you don't see any chips or shavings STOP !!!! get a new bit . Once it gets work hardned You are in a world of sh-t private pyle.:drink:

 

[gsganzer]

I drill stainless all the time. Definitely use a drill press if possible. I use plain old tap/die lubricant from Home Depot or Lowes. If you're drilling a large diameter hole like 1/2", do it in steps (e.g. 1/8", 5/16", 3/8" then to a 1/2") Work hardening is the biggest issue.

 

[void777]

^^^^^ If it was me i would take oldpath05 advice even thin stainless will melt none hardend drill bits.

 

[oosik]

A sharp bit - go slow - most any kind of cutting oil. Speed & heat are your enemy.