Drilling Steel?

[gez]

How the hell do you drill sheet steel??

I drilled some today (I recut the bracket of a top-snare mechanism to improve the sizzle).  Only thin stuff (0.7mm or 0.5mm, can't remember which), but my drill bits, all for metal, barely made a dent in it with my trusty power drill!  After a number of minutes of drilling the dent was deep enough to have thinned the metal enough to drive a nail through, and then it was easier to drill through it.  Once the hole was opened up enough to get a varibit in there, it was plain sailing; but how to drill the initial hole?  The bits I was using (both now blunted) were 3mm.  Is (slightly) smaller better, or should I have used special bits?

How do the big boys do this?  Punch holes rather than drillng? Or do I need one of these:



Managed to get the job done in the end, but what a bleedin' palava...

[OscarMeat]

Seems strange...was the metal just plain steel or maybe "rust-free" stuff? That won't budge with a normal drill bit.
I would buy one or two special bits for steel sheet. I have couple of bits made of volfram, so they cut easily thru even 1.8mm sheet.

I've made a few stomboxes of 1.25mm steel sheet, bent and drilled, then enameled. Makes a tough little box

[Nasse]

Dunno if it was your problem but big boys told me drilling certain types of stainless steel is very troublesome or almost impossible, and I think they did not lie to me. We had a very good drill press at the workshop at those days and they told me to use cooling/lubricating liquid and not burn the drill bit by doing it too fast or with too much pressure. Those thick things were zinc-plated Fe 37 B and not stainless steel, but it needed a steady hand anyway. Talking about drill bits I bought a supercheap set for woodworking, and they were totally crap, not useful at all.

[gez]

Seems strange...was the metal just plain steel or maybe "rust-free" stuff? That won't budge with a normal drill bit.

Ah, that might be it.  It's 'mirrored stainless steel'.  I've widened holes in steel enclosures before, but never had to cut them from scratch.  I didn't think it was going to be that difficult!  Well, the upside is it's incredibly strong so I don't think I'll ever need to replace the bracket!

[OscarMeat]

yep, stainless steel    is hard stuff to drill. I've used laser cutting at my work if I needed more than one hole to a plate.

[dschwartz]

i ruined most of my drillbits drilling steel studs..
i used to make deep indentations on the surface with a hamer and one of those big nails for marking drill poins..if the drill didn´t cut in, i would deep the indentation more and more, till the bit passed thru

i remember the effort, brutality and danger that drilling those things are..i really don´t know how i still have my 10 fingers complete...

[Mick Bailey]

Mild steel drills easily, though thin sheet can grab as the drill breaks through. Clamp the work and back it up with a piece of timber, MDF, ply or chipboard to support both the work and the emerging drill.  A little lubricant helps, but isn't essential if you're only drilling a few holes and are using HSS bits.

Some materials are very prone to work hardening, especially if the drill skids or drilling pressure is too light to maintain an effective cutting action. Some stainless steels and certain bronzes can be quite difficult to drill because of this. I've recently done a job involving drilling hundreds of 3/8" holes in thin stainless sheet that required the bit to be resharpened every 5 holes and the swarf came off red hot.

You can buy special drills for difficult materials with different geometry, alloys and coatings - the reference is the 'Dormer Twistdrill Handbook' which goes into a lot of detail on the subject. I've always managed with standard HSS drills and have modified the cutting angles to improve drilling too-soft or too-tough materials with a great deal of success.

[drewl]

Get a turret press!
Bad memories from when I was running a machine shop......I was doing CAD and they needed someone to run it.
Damn, I could have run off enough amp chassis' and boxes to last me a lifetime If I'd only known

[The Iron Chef]

Get a "split point " drill bit. (do an image search) This style needs much less pressure to start pulling a chip. Stays centered better too. Use a drill press if you can and be carefull.  The drill press is the most dangerous tool in the shop. imho
-Keith

Ah, make sure your drill spindle is not running in reverse. im not kidding.

[gez]

Get a turret press!

Unfortunately they seem to be very expensive.  However, this punch looks like it should do the job:

http://www.toolsnstuff.co.uk/product_info.php?products_id=3774

As I said above, once I can make a hole big enough for the varibit it's all plain sailing so I think a punch would be the way to go.  Having said that, the job is done; but, because one of the holes ended up askew, the snare wires run at a slight angle.  Makes no difference to the performance of the drum - it now sounds incredibly good (huge improvement with the new fixing attachment) - but knowing that it's slightly askew is giving me sleepless nights ( ).  I might re-cut it (I still have spare sheet steel); if I do the above would be the cheap way to do it.  Unless it's a false economy?  Anyone used one?

[5thumbs]

Dunno if it was your problem but big boys told me drilling certain types of stainless steel is very troublesome or almost impossible, and I think they did not lie to me. We had a very good drill press at the workshop at those days and they told me to use cooling/lubricating liquid and not burn the drill bit by doing it too fast or with too much pressure. Those thick things were zinc-plated Fe 37 B and not stainless steel, but it needed a steady hand anyway. Talking about drill bits I bought a supercheap set for woodworking, and they were totally crap, not useful at all.

Nasse brings up a very good point about lubrication, drilling pressure and drill speed.  I've drilled a lot of holes of a wide variety of sizes in all sorts of steel when repairing farm equipment and other stuff.  I've found the speed guide inside the lid of my shop drill press to be very useful in determining a good speed for a given hole size on a given material.  Spinning the bit too fast with too much pressure burns up the drill bit, as well as can make the bit jump a lot and/or grab the work piece and bind up.  If the bit is working properly and properly lubricated, you don't need much pressure to maintain drilling progress.

Lubrication and patience are very important.  I use thread cutting oil, but I imagine plain old mineral oil in a pinpoint squirt bottle would be just fine.  I use a center punch to get a starting dimple.  If I'm drilling a larger diameter hole on a thick piece, I'll usually start the hole with a 1/8" bit and drill at least 1/4" into the work piece.  I apply a drop of lube to the starting dimple and drill until either the lube dries up or starts to smoke.  Every time that happens, squirt more lube between the tip of the bit and the work piece, then continue patiently drilling.

I've drilled up to 1/2" holes in 1"-thick galvanized, cast, hot-rolled and cold-rolled steel using this method and it works fine.  I developed this methodology after burning up a couple of bits in a drilling experience very similar to yours.  Hopefully it will prove useful for you as well.

Good luck!

[R.G.]

Steel is not just steel.  There is a simply incredible variety of steels. Some are so soft,  they are hardly structural at all. Some are so hard that they are difficult to cut even with solid-carbide tools. Some steels turn to butter when you get them red hot. Some tool steels retain their strength so well at high temperatures that they can be used to bore holes in files by friction - the heat melts the file under the bit.

Stainless steel is an interesting one. Even when it's annealed to as soft as it can get, it work-hardens so fast that if you drill it too slowly, it hardens under the bit itself and will blunt the bit. So if you drill stainless, don't dawdle.

Saying "steel" is a little like saying "rock". There's a lot of variety.

[gez]

Saying "steel" is a little like saying "rock". There's a lot of variety.

Yes, this little 'detail' is slowly sinking in!   

[Paul Marossy]

I had a steel amp chassis given to me from some parted out cheapie SS amp that I used to make my Octal Fatness. I had to drill a few holes in it for the tube sockets, and some spade bits made for wood worked just fine, I just had to go slow. Then I have had some other enclosures that I thought were mild steel, but they ended up being some of the hardest things I ever tried to drill!

[timotet]

most stainless steels will work harden , as in the surface hardness will increase as you try to drill it especially with a hand drill.
when this happens you can kiss your drill bit good-bye!
with stainless a low rpm (spindle speed) with a heavy chip load (cut) works well with coolant or cutting lube.
make sure your part is held in a vice or clamped to a solid work surface.
it sounds like a small bench top drill press would be a good investment for you! so you dont break your wrist with dreaded hand drill hook up.(ouch)

just my 2 cents

[gez]

it sounds like a small bench top drill press would be a good investment for you! so you dont break your wrist with dreaded hand drill hook up.(ouch)

I have one, but it's only for a hobbyist-type-drill (similar to dremel in size).  Great for PCBs, not so great for the aforementioned job. 

I think the punch is what I'm looking for: if I was able to drive a nail through the stainless, then a punch should work.

[FisTheGoon]

Good topic man.
I have experienced such thing.The bit just won't drill thru the steel.Found out that u must start with the smaller bit n gradually  change to bigger bit.Also the speed must not be fast cause it done nothing to the steel.Lubricant is a must to reduce friction.And 1 more thing the drill bit will sure to be blunt after drill and need to be sharpen.Even 1mm thick is a pain in the ass to drill.  

[petemoore]

  Lube runs down drill shaft, even gets waylayed by...cotton taped there to slowly release a little oil...doing a lot of drilling ? put an oil wick on it.
  Slow and dern stiff pressure +1.
  paper cup for water cooling is an option, hopefully between the oil and the steel cut the heat of the blade is dissipated, but bits soften when temperature exceeds a certain amount.
  For wood, sharpening is an option, for SS, especially for starting, a new bit is the best and only option, new doesn't last very long though...perhaps diamond?..just to get a scratch started?
  I had a pretty good record of bit rate at work, 1 don't break it by bending, 2 use the new bit to get a scratch started, 3 use the good bit to finish the rest of the hole, and oil wick.

[AL]

Drill press, some kind of coolant and a lot of patience. Yep.

It's a major PITA drilling with a hand drill. I used to work in a shop and I can't tell you how much fun it is when your electric hand held catches as it goes through... and jerks your hand around with it. It's a miracle I didn't break my wrist. I hated drilling steel.
AL

[Paul Marossy]

It's a major PITA drilling with a hand drill. I used to work in a shop and I can't tell you how much fun it is when your electric hand held catches as it goes through... and jerks your hand around with it.

I use a hand drill for stuff like that, don't have a drill press. I have learned how to predict that catch when it starts to punch thru and how to deal with it. I've had my wrist jerked a few times before that, too!