Tips For Drilling Stainless Steel

[MEXICOWANDERER]

"Tips" does not denote authoritative last-word instructions, rather ideas that help folks who are first timers or frustrated second timers.

Very expensive made-in-USA (Germany / Sweden) drills are worlds apart in effectiveness and durability than Oriental drills. In fact I have had better luck with uncoated M2 drills than with so-called titanium plated Oriental drills.

Made in USA, titanium plated drills are excellent but they are prone to damage if spun at too high a speed even for a few seconds. When the titanium disappears from the point the drill is simply plain M2 steel.

Carbide drills are fragile. They are harder than any other drill but one malforned curl in the hole can chip the tip. I have no idea how to sharpen a chipped carbide drill.

Cobalt drills are solid specialty steel. Good quality cobalt drills can be a lifetime investment if they are resharpened correctly (another thread).

I do not know of a way that stainless steel can be drilled rapidly. In fact speed seems to be the big-enemy of anything used to try and drill A4, 18-8 or 316 stainless steel.

But I stumbled across a tip that really surprised me...

WD-40, cutting oil, tapping oil or whatever is not the best stuff to use when drilling stainless steel. Not by a long shot.

Make up a sprayer pump bottle, maybe a pint. Put one tablespoon of liquid dishwashing soap and slightly less than a half teaspoon if liquid clothes washing bleach in with the water and fill the bottle.

A gunsmith machinist patiently explained that "Lubrication is definitely not what the drilling process needs. It's cooling of the work area and tool. Soap makes the water "wetter" and water is far superior to oil in carrying away heat. The bleach makes the cutting action more aggressive".

I would believe there is a limit as to the capacity of the mix to cool the bitter edge of a cutting tool so lower speed is still essential to not destroying the cutting tool.

I've been using this trick for years and now I used it when drilling regular steel. It really works and in the end the far easier and more complete cleanup of water versus oil makes it a winner in my mind.

Sometimes in stainless steel I drill at 60 RPM so slow is mandatory.

You bet! Comments are welcome!

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Quote:

Thanks... any tips on thin stainless not turning blue? Is blue from heat? If so maybe go slower?
Thanks


If you are getting discoloration of the metal during drilling you are running too hot and are risking ruining the drill bit.

And you are work hardening the stainless.

[maillemaker]

Thanks... any tips on thin stainless not turning blue? Is blue from heat? If so maybe go slower?
Thanks

If you are getting discoloration of the metal during drilling you are running too hot and are risking ruining the drill bit.

[Lynnmor]

Use a speed feed chart for machining metals, just Google and select one that you find convenient. I have a tool & die shop and use a chart often even though I might already know the correct speed. There is a wide variety of stainless steels, some are free machining and a pleasure to work and others will fight you all the way.

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Housted wrote:
One other thing to consider after drilling. If you use a stainless bolt and nut you need to put some anti-sieze on the bolt because stainless will sieze and weld it self if both nut and bolt are clean. Don't ask me how I know!!!

Yes - Very important
This phenomenon is known as Galling, it is caused by the heat pressure and friction.
If you have ever tried grinding stainless you will notice the metal doesn't shear off cleanly as carbon steel does, some of the metal will just move in the direction it is being ground .

[Housted]

One other thing to consider after drilling. If you use a stainless bolt and nut you need to put some anti-sieze on the bolt because stainless will sieze and weld it self if both nut and bolt are clean. Don't ask me how I know!!!

Housted

[fourthclassC]

Agree with all above. I have to add what my son just told me, keep the bit cool by on / off pulses while drilling stainless. I think many above may use this method but I thought I would spell it out specifically.

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I have drilled a lot of stainless and found a small brad point drill bit worked best for the pilot hole.

And don't forget stainless work hardens so you want to use sharp tools and a coolant, if you are tapping or cutting threads don't let it heat up go slow and easy.

If you use a dull drill and the stainless work hardens your in for a really big hassle.

[MEXICOWANDERER]

Agree 100% about Japan and knives. But for tooling even the Czech are a fair bit better than even the Japanese. But then again NTN bearings are superior. But Korean, Taiwanese, Chinese, Filipino, Vietnamese, Thailand, and Indonesia are way behind the cut.

USA electric furnace steel alloy is the finest in the world and the priciest per gram weight. How Germany can beat the retail prices in the USA is beyond me. Maybe greed enters into this...I managed to get my mitts on one, a single drill from Lockheed. Very short like an aircraft special. Had a built in depth stop. Heaviest drill for it's size I have ever picked up. The drill was hidden in a four foot wide spool of electric wire. A man passed behind me and remarked "Don't let them see that. They have a serial number and are not allowed to leave"
Sure as heck a man in slacks with a white shirt, tie and ID clipped to his pocket walked up and said "Sorry, that 'piece' is not part of the auction".

Dang!

I did however get a roll of 19 AWG wire. Silver color throughout, not copper. But it soldered like a champ. A tad under nine pounds spool and all if I remember right. Some light-fingered @#$%&! walked off with it in the yard a week or so after I brought it back.

I used some of the cobalt Milwaukee drills I bought a couple of weeks ago. They are good quality (always suspicious of sale items from Home Depot).

[Tom_Barb]

I have found a Roper Whitney punch works better than any drill.
That said they are pretty limited as to how far they will reach, but for along the edge, they can't be beat.

Also a Multi bit works better as a step dril,l than most other drills, again run slowly

[obgraham]

Don't you think it is the quality of the tool rather than its origin that matters?

Sure, a lot of Asian tools are made very cheaply. That's why we often buy them.

But some Japanese blades can be among the finest in the world, and also among the most expensive.

[MEXICOWANDERER]

Drilling Monel is difficult. Drilling K-Monel can drive a person to drink.

I had to use 4 progressively larger drills to put 7/16" holes in the coaming for my generator shed door. Ten holes took me two days. It beat me up. On top of it all I had to use a D handle 275 RPM drill for the last stage. A D- Handle drill is especially good at staying still and having the person doing the drilling go-round-and-round.

I bought a bunch of titanium strap from Lockheed for whatever temporarily insanity reason I had at the time.

When all my attempts at welding and drilling it failed miserably, I took it to a big machine shop. No matter what I asked, the answer was "NO!"

Titanium is not "as light as aluminum" but I danged near broke an 8" Wilton vise trying to 90 degree a 3" x 3/16" strap with a hammer. I turned a torch rose bud on it which seemed to amuse it.

[Ralph_Cramden]

Earl is your friend, and just about any Earl is better than no Earl at all, even some black used motor oil...Chain saw chain oil works really well, and low speed. We use a lot of 304 SS angle for structural hangers with pre cast concrete at water and sewer plants.

[Doughydman]

Center punch hole, Drill slow, push hard, use some kind of coolant. Lots available. If hole is very big drill pilot hole (bigger than 3/8”)

[fj12ryder]

Yeah, the new style Tap Magic is more soap-type lubricant than the old Tap Magic which was discontinued. I think it had some pretty nasty ingredients. The new stuff works but not as well as the old stuff. Some stainless is not very easy to drill. Tough more than hard. If it's turning blue your drill speed is too high, and/or your drill bit is dull, and you're burning up your drill bit to boot.