Drilling through Stainless Steel

[ArtS]

Thanks Barry.

ArtS

[Trevor]

Hi there

All you need to do is make sure that

1. Your drill bit is sharp.

2. The drill needs to be made from "High Speed Steel" marked "HSS" on the shank.

3. Be aware of the heat that the drill will generate which could damage the leather.

Good luck

Trevor

"Way Down Under"

[GampasShop]

The #1 problem most people have when drilling thru SS is the drill speed. Keep your drill RPM's low and any bit will drill it. If you just pull the trigger all the way you will go thru bits faster than you can chuck it up. When drilling SS you want your RPM's somewhere in the 350-500 range, which if using a 3/8 drill most of them are geared in the 1500 rpm top range. Just take it slow and when it is removing chips good, DO NOT GO ANY FASTER.

Many years of working as an electrician in meat packing facilities has taught me this. Many of the guys I worked with never did catch on.

[Art]

Hi Art,

Big blocks of stainless should be normalized or annealed before machining, but when I have had to tackle heat treated stuff, I go to a company named Guhring for bits. I get bits and end mills from them that are made of micro fine carbide and coated with a multi-layers of titanium nitride and titanium aluminum nitride. These things are run at high speed and feed rates and without coolant (air jet cooling is ok though), this is opposite to what we learned for HSS bits. I haven't bought in a while and am sure they have improved even more. They also produce PCD (polycrystalline diamond) bits, but I have never wanted to drill a hole in carbide. Down side is the cost, an 1/8" jobber length bit costs around $50-$60, however will last thousands or holes in thin stainless, and they can be resharpened (by Guhring). Run 'em fast, no liquid, it is a little scary at first, especially when you are abusing the crud out of a $60 bit or $200 end mill. Don't do anything over HRC 90 (I'm serious), yes, I did type ninety. The folks at Guhring tech support are good too.

Art

I put a piece of stainless steel between the layers of leather in some of my holsters. The problem that I have is drilling a hole through it. It's a thin piece of strapping, maybe 1/16 inch thick. I just wear out drills. There must be something I'm doing wrong. I dip it in water every so often to keep it cool. I need some advice please.

Help please.

ArtS

[ArtS]

Thanks. I see one thing I was doing wrong right off - I was drilling too fast. I was cooling with water but I'll get some cooling oil or fluid.

The $60-$200 are too steep for me but I'm going to go get a cobalt bit. I only need the one size for the snap shaft to fit through. I found a Fastenal near me.

Thanks again everyone.

Art

[Davy]

I drill ss every other day . Its no big deal if you go with Trevors instructions , he was bang on with what he advised . Dont worry about coolant unless its thick gauge steel . Should only take half a sec to drill through 1.5mm ss .

[WilliamWood]

OK. First of all, you will have to slow the drill down as slow as it will go. (For a 1/8", I'd advise no more than 200 RPM.) Use a good quality High Speed Steel drill bit that is very sharp. Use a fair amount of feed pressure (how hard you push it into the work). Practice on a scrap of the Stainless. Stainless steel comes in many grades. If it is thin sheet, it probably is Grade 302 or 304. That is type used to make stainless steel food prep tables and equipment. 302-304 Stainless is stainless (actually it is stain resistant - ALL steel will corrode or rust under the right conditions) because it has a very high percentage of both nickel and chromium. Those two metals also make it very susceptable to a condition known as "work hardening" if the drill is allowed to rotate on the surface at enough speed without removing metal. As it spins on the surface, it gets that spot hot from the friction. The metal under the drill bit actually gets harder than the bit. DO NOT try a carbide tipped or a "Diamond" bit as the stainless in these grades is so "gummy" it will actually break down the carbide and "snatch" diamond dust out of the drill bit. It will ruin one of these hideously expensive bits instantly! Usually, if several holes are needed, I'd advise a punch of the type used in sheet metal fabrication. (A good Air Conditioning and Sheet Metal shop can help out here, and it's a bargan at almost any price. Otherwise, just remember: SLOW RPMs, Heavy Feed , Sharp HS Steel drill bit. (How do I know? 30 years as a Tool and Die Machinist and Gunsmith.) Also: Clamp the piece down firmly when drilling. The drill bit WILL grab the piece when it cuts through. Use a drill press if possible and clamp down tight on the table. If a hand drill is used, get a variable speed, run slow, and put the piece in a padded metalworking vise.

I try to avoid 302 or 304 if possible........... too old for that kind of stress and frustration....

[fire]

I've had good luck using step bits for stainless.

[Sharpshooter]

My shop is attached to a knife company... they drill all different sorts of stainless steels after heat treat so it is possible.

Drill speed is critical... also with very thin materials it will grab the bit as you poke through. 1/16" is pretty thin and you MAY be better off punching through like we do with leather. I don't think you mentioned the hole size...

The Knife shop uses Carbide Bits, not carbide tips, carbide bits. If you can't find a specific size, let me know and I'll find the source for you.

Damn.... I'm pretty spoiled with my setup... none of these things are problems for me so long as I

m willing to walk a whole 30 feet. Let me know if I can help.

[ArtS]

Thanks everyone for the advice and help.

The Major took care of me as far as the bit and now I'm going to make myself a holster for my Makarov .380. So I'm going to try it out and also a new design for the thumb break.

Well not a new design - just new for me but old for the Ross Company.

I'll post it when finished.

Thanks,

Art