Drilling thru stainless steel?

[Rt3]

OK, I'm trying to fix a rifle magazine and I've got one big hurdle...I can't figure out how to drill holes in the mag body, which is only about 1/8 inch thick. Someone mentioned that it's probably stainless steel...

I've tried everything: hand drill, drill press, HSS bits, cobalt bits, carbide bits, drilling with cutting oil, drilling dry, "pecking" (had to look that one up)...nothing is even making a dent in that steell!It's frustrating as heck.

The only thing that's even helped a LITTLE bit is using a Dremel with a diamond burr; that at least put a bit of a dent into the metal, but unfortunately the burr tip is too large for the size hole I want (1/16").

The most recent thing I've tried (suggested by someone else) is heating up that part of the mag body with a propane torch, and then let it air-cool, which was supposed to soften the metal enough for the drill bit ti "bite"....but that was another failure.

So...really...anyone...what's the secret to drilling thru this thing? A $20,000 cutting laser? Explosives? Is it even possible with home tools (inexpensive drill press), or is that an impossibility?

Rt3

[Long Tom]

I'm not aware of a stainless that CARBIDE won't cut. You must've work-hardened it in the early going rubbing HSS against it with too little pressure to start a cut...

How are you fixturing it?

A diamond tip masonry bit might be the easiest solution at this point. Available in various sizes at you local home improvement store.

[Rt3]

Sorry for my ignorance, but a diamond-tipped masonry bit...I see those advertised on Amazon...they are blunt-tipped, correct? As opposed to the "hammer-type" masonry bit, which is spade-shaped?

[earlgo]

Bob Brownell's Gunsmith Kinks II has several pages on spot annealing, but none address a stainless steel magazine. The suggestions may be helpful though.
I have found that there are a lot of suggestions on how to get out of sticky wickets in his books, vols I,II and III.
F. Brownell & Son, Publishers, Montezuma, Iowa, 50171, USA 1983
If you are a starting-out gun repair guy then I'd suggest these books as a great start.
They might be available at your local library, assuming you get there before they are stolen... I mean permanently borrowed.


--earlgo

[oldvan]

EDM would not care about the hardness of the material, and some folks have come up with thoroughly impressive homemade sinker EDM machines.

Here is a video of one.

[stevec]

Long Tom,I've never seen a 1/16 dia. diamond tipped masonry drill.
Rt3, I don't know why you suspect it's stainless, is it just because "someone mentioned" it.

My question is, what speed were you turning the 1/16 drill? If too slow it could "work harden" the steel before cutting it.

I don't know exactly what speed to recommend for your application but someone on here knows.

Harold, jump in here please.

[Rt3]

Bob Brownell's Gunsmith Kinks II has several pages on spot annealing, but none address a stainless steel magazine. The suggestions may be helpful though.
I have found that there are a lot of suggestions on how to get out of sticky wickets in his books, vols I,II and III.
F. Brownell & Son, Publishers, Montezuma, Iowa, 50171, USA 1983
If you are a starting-out gun repair guy then I'd suggest these books as a great start.
They might be available at your local library, assuming you get there before they are stolen... I mean permanently borrowed.


--earlgo

earlgo,

If I was going into the "business" of gun repair, I wouldn't mind spending the bucks on those books (they sound interesting anyway), but I'm not into gun repair. I'm just a guy who wants to fix a rifle magazine without spending a bunch of money. Unfortunately, now with purchasing all the other drill bits recommended by the local hardware store, I've gone over my gun-related budget for the next month. So it looks like I won't be able to do anything with this for at least another month.

[Rt3]

Long Tom,I've never seen a 1/16 dia. diamond tipped masonry drill.
Rt3, I don't know why you suspect it's stainless, is it just because "someone mentioned" it.

My question is, what speed were you turning the 1/16 drill? If too slow it could "work harden" the steel before cutting it.

I don't know exactly what speed to recommend for your application but someone on here knows.

Harold, jump in here please.

stevec,
I didn't think about it being stainless until I mentioned to someone about the problems I was having. Then when they said it was probably stainless, that did make sense to me, since it would be a part that might get wet (carrying it in the rain, for example), but you wouldn't want it to get rusted. But, yes, that is still an assumption.

When I first tried drilling it (with the other drill bits I mentioned previously), I tried both slow and fast...I couldn't tell you what speed I was using in my hand drill, but on the drill press, I'm pretty sure it's set around 2500 rpm.

So, if it's been work hardened, is it impossible to drill it with my simple home tools? After heating it up with the propane torch, shouldn't that have softened it back up? Or am I totally out of luck now, without finding someone with an "edm" machine?

[Russ Hanscom]

A few observations. If the part has work hardened, it cannot be annealed unless the spot is heated to red heat then cooled slowly. I doubt you got it that hot so it still probably as hard as ever. Also, heating it up is going to damage the finish and possibly do other bad things.

A test with a magnet will partially answer the stainless question. I know zero about guns but if you post a picture or the make and model of the one in question, probably someone knows the specifics.

For a 1/16" hole, the bit should be turning well over 2500 rpm - but 2500 should work.

Recently I had some extremely 1/16" dia hard screws to remove, a quality HSS bit would not touch them. I had an assortment of small carbide drill bits use for circuit boards. I put one in the Dremel and with a modest speed setting, had no problem drilling out the screws. Since I was hand holding the Dremel I broke a bit or two but they were expendable. Go to ebay and look for carbide bits and burrs - ones with a 1/8" shank and about 1/16" cutting end are in the under $2 range - originally used for drilling PCBs. Typical ebay item #161420412689.

Not sure about your local hardware store, but none of the ones I frequent would have a clue about drilling hard stuff.

Hope this helps.

[Glenn Brooks]

If it is stainless and is work hardened you may never get through it with tools at home. I tried drilling some 1/2" stainless plate, that was polished and burnished till it shone, and eventually took the work to an industrial grade machine shop. They ruined many bits trying to drill the requested holes in two 12" long pieces. May be simpler to buy another magazine.

[Rt3]

Go to ebay and look for carbide bits and burrs - ones with a 1/8" shank and about 1/16" cutting end are in the under $2 range - originally used for drilling PCBs. Typical ebay item #161420412689.

Not sure about your local hardware store, but none of the ones I frequent would have a clue about drilling hard stuff.

Hope this helps.

Thanks for the info about the ebay bits, I'll give that a try.

Yup, I've come to the same conclusion about my local hardware store

[Harold_V]

Long Tom,I've never seen a 1/16 dia. diamond tipped masonry drill.
Rt3, I don't know why you suspect it's stainless, is it just because "someone mentioned" it.

My question is, what speed were you turning the 1/16 drill? If too slow it could "work harden" the steel before cutting it.

I don't know exactly what speed to recommend for your application but someone on here knows.

Harold, jump in here please.

Too many variables to provide reliable guidelines.
Some things to ponder.
Stainless is not generally hard, although once work hardened, it can be way too hard to machine with HSS. A file should skate over such a piece without removing anything, aside from teeth from the file.
It would seem ulikely (to me) that any grade of stainless beyond one of the 300 series would be used if corrosion resistance was the purpose. None of them are magnetic, but that doesn't preclude the possibility of them being hard (work hardened).
I took note of Russ' comment in regards to annealing work hardened stainless. Assuming it's one of the 300 series, how quickly it cools plays no role in hardness. Red hot stainless of the 300 series would actually benefit by rapid cooling after annealing, as that limits intergranular corrosion, to which these alloys are subject between the temperatures of 800°F and 1,500° F. These alloy does NOT heat treat, as it is too low in carbon to do so.

I fully expect that a carbide drill, short, run at considerable speed, would drill that stainless, even if it was work hardened. I'd avoid heating, as that is likely to distort the item, rendering it useless.

No, I am not a gunsmith. Just a machinist/toolmaker!

Harold