Some types of steel undrillable?

[paul simonson]

New to metal working, bear with me.

I am modifying some brackets and have found to my surprise that I can't drill holes in some of them. I am using a powerful hand power drill and HSS bits, (these ones http://www.screwfix.com/p/dewalt-3mm-extreme-2-hss-drill-bit-pack-of-2/30294)

Are there types of steel that are impossible to drill into?

I'm drilling into 2mm stainless steel for example. And my drill barely marks it. Then I use the same tools on a 2mm sheet metal and go through easily.

What don't I know?

[John K Jordan]

I am a strictly amateur metal worker but I do machine and make things out of various metals. Some types of stainless steel drive me crazy - they quickly dull metal-cutting saw blades and drill bits can't touch them. Others stainless steels are manageable. I'm afraid I don't know my stainless alloys and when I run into a problem I try another type of bit, cobalt or solid carbide, for example.

As for other types of impossible steel, yes, hardened high-carbon or tool steel is impossible to drill. It's like trying to drill into a file. One thing to do for hardened (non-stainless) steel is to anneal it with heat, drill, then re-harden if needed.

Another way to cut holes in any kind of steel is with a plasma cutter. That's what I reach for when cutting stainless steel plate - mine will cut up to about 1/2" like a hot knife through butter. If the holes you need don't have to be precise, someone with a plasma cutter could burn some in a few minutes. Water jet will cut stainless too but that's way out of my league.

JKJ

[David Stine]

Yes, there are some kinds of stainless steel that work-harden. These are, generally, austenitic stainless steels, which is mostly the 3xx series of stainless steels. The most common alloys will be 302, 304, 308, 316 stainless.

OK, what does 'work hardening' entail? This means, as you're machining, or filing, or deforming (eg, swaging, bending, etc) the stainless, it will become hard, sometimes quite hard, in the area of deformation. For your application, this will mean the bottom of the drilled hole, which will then turn your HSS drill bit.

First, you need to cool the drill bit's point. You'll need

In your situation, you need your HSS bit to be as sharp as possible. You need to make sure the RPM's of your drill are not too high, and not too low. You need to be sure you're getting a high enough feed - you don't want to allow the drill bit to just skid around in the hole. You need to get the bit cutting, but not cutting too deep a chip, which will then cause very rapid hardening and probably break off the bit because the chip won't break off.

Overall, I would recommend that if you can, you drill the brackets using a drill press, and slow down the RPM's.

[John Ziebron]

Although I've heard of guys using standard HSS drill bits for stainless steel my training and experience has always been to use either cobalt or carbide tipped drills. The key is to use a slow speed and if it's a hole larger than say 1/4 inch drill a small pilot hole first. If you type in "drilling stainless steel" on YouTube you will find some helpful videos.

[Malcolm McLeod]

If you absolutely have to have holes in the particular piece causing your drilling woes, you can look for a machine shop that can do EDM (electrical discharge machining). Its been 30 yrs since I was around tool and die/molding biz, but as I recall EDM would cut any composition of steel, regardless of hardness.

[michael langman]

Center punch your hole location heavily with a good center punch. Then take a 1/16" drill and drill a starter hole at 1200 rpm minimum. Then drill your finish hole.

[Terry Beadle]

You might want to look into buying some carbide drill bits.
They will go through most hardened steels.
Expensive though.

Regards,

Terry

[Jim Finn]

Rule of thumb for drilling metal , including stainless. Pilot hole, lubrication,slow speed and lots of pressure. (Drill press) When the metal comes off in ringlets or large chips you are doing it right.

[Eric Keller]

I have found bed frames to bevirtually undrillable. I have no idea why that might be.

Really, you have to follow the proper feeds and speeds and use cutting fluid. Then most steels can be drilled. Unless you go out of your way to find something hardened or a high-alloy steel. I have some stainless that is a real pain to drill.

[david privett]

If I am not mistaken bed frame is a spring steel and some kinda hard I use a cut off wheel to cut it. I weld it ,no drilling with what I got.

[John Ziebron]

I have only drilled bed frame metal once and had no problem. But I used cobalt drill and some cutting fluid along with the proper speed of course. I can understand that all bed frames are not equal. But I can't believe none could be drilled because they can't be too hard or they would be too brittle for the application. Worst case is that you would have to use a sharpened carbide tipped bit.

[Eric Keller]

I know bed frames aren't really that bad with proper technique. However, it always seems that when I want to drill one, I only have a hand drill. That makes speeds and feeds a bit of a problem. They definitely are something other than mild steel.

[Marc Jeske]

Ditto on the bed frame drilling problems, I made a number of mobile stands using scrap bed frames, ended up buying and welding on plate casters rather than drilling.

Bed frames definitely can be drilled, but w a drill press w lottsa pressure, wearing eye/face protection.

Sometimes Thrift Stores get an overstock, and throw them in their scrap metal pile.. a great source to make "free" welded tool bases.

Cuts just fine w abrasive chop saw.


In my opinion, in OP case, I would try to high pressure hog through w a drill press. Marc

[Kevin Beitz]

Next time you have a problem drilling a hard steal try a cement bit. You might need to sharpen it a little because even new they aren't sharp. You can drill a ball bearing with one. Be careful when you get to the end of the hole because the bit will catch and snap off.

[John K Jordan]

Next time you have a problem drilling a hard steal try a cement bit. You might need to sharpen it a little because even new they aren't sharp. You can drill a ball bearing with one. Be careful when you get to the end of the hole because the bit will catch and snap off.

By "cement bit" do you mean a carbide masonry bit?

[Bruce Wrenn]

I have found bed frames to bevirtually undrillable. I have no idea why that might be.Bed frames are made from old railroad rails. When I need to drill a hole in one, using drill press equipped with a cut off 16d nail, soften spot where hole is to go. Both nail and rail will turn red, which means temper is gone. Then drill with sharp drill, and plenty of lube, preferably using a drill press. As for why bed frames are spring steel, just think about the stress they encounter with a couple 300 pounders making whoopie. On second thought, don't think about that

[Marc Jeske]

What is "Whoopee" ?

If it's "Whoopie Pies", those are made in the kitchen.

Please explain, crisp hi quality images may help.

Marc

[david privett]

two 300 pounders yuck do not want to think about it much less explain it.

[Kevin Beitz]

Any time I have steel that refuses to be drilled I get out an old cement bit.
Put a sharper edge on it and go to drilling. I drilled through a ball bearing just to show someone I could do it.

[david privett]

what do you use to sharpen the carbide wings of the cement bit? I thought it had to be something like a green wheel. And what angle do you use?

[Bruce Wrenn]

What is "Whoopee" ?

If it's "Whoopie Pies", those are made in the kitchen.

Please explain, crisp hi quality images may help.

MarcMan, you are SICK!

[Kevin Beitz]

A normal stone will do it, but it's hard on the stone.