Drilling hard tough steel plate

Is the material magnetic? If not, it's likely stainless, as has been already noted.

Depends on the material. Heating it will anneal it, assuming it's carbon steel, or even 300 series stainless. How quickly it cools spells the difference in annealing, or not, if it's carbon steel or one of the various carbon cycle alloys. It need not cool for 24 hours, just don't quench it. As soon as it's cool enough to handle, you should be able to work it. If you heat a specific area and not the surrounding area, the heat will be dissipated too quickly for a perfect anneal, so don't get a spot hot and move on, play the torch on the general area so it cools slowly. If it's stainless, simply heating and cooling quickly will anneal it.

You've been handed some good advice, assuming the material is stainless. Use sharp tools, don't allow them to tarry, run at a slower speed, and use a generous amount of oil. Once a drill work hardens a hole (especially in stainless), your drill goes to hell almost instantly and squeals like a stuck pig. It also makes a strange sound, grabbing and releasing quickly. Look for considerable damage to the drill margin if that happens. Simply sharpening the drill won't fix the problem, you have to push the drill back past the damage. Don't go back in the same hole if you can avoid doing so-----unless, of course, you anneal it.

Harold

What Harold said about the "instant" part. It really is that fast.

OTOH: I did a demo: 1/4" standard quality McMaster bit, 3000 rpm >

if you work harden the metal in the hole, try resharpening the bit and go back in real slow with a lot of pressure. As soon as you cut a couple of turns of the drill, pull it out and resharpen it again. Make sure the outside corners aren't worn. You can ususally get a good hole started again with the double resharpening.

John

I had a problem drilling some Mo Max - tool cutting steel one time.

What I did was use a carbide drill - a solid carbide - not the concrete drills.

You can buy them lots of places - I got mine at MSCdirect.com The drill can take the heat and cut. The one I had got red hot and bore through. Afterwards after normal air cooling the drill was just as sharp.

I didn't have the option of annealing the tool at the time - and took the easy and fast way out.

I'd suggest plenty of coolant as you drill to take off the heat. If you can't then be sure to use Carbide.

Martin

Martin Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH & Endowment Member NRA Second Amendment Task Force Charter Founder

Bob AZ wrote:

see

Uncle George

Bob -

Remember drills don't drill the center area out. It just mushes around. In soft metal, it mushes sideways and is scooped out.

Drill a small diameter pilot hole - smaller mush area :-) - and then this hole becomes where the point barely turns around in - doing nothing. The outside diameter lips cut out.

My dad taught me to work up through drills.

If your small drills can't - then use a solid carbide drill to give you a start.

Lube - lube - lube - keep it cool so you don't harden the area even more.

The carbide drill can get red hot in the drill method (like mine) - anneals the metal and starts the drilling. Let it air cool in the press - won't take long.

Once you have a hole - continue up the sizes until you get to the 1/4 you want.

Martin Martin Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH & Endowment Member NRA Second Amendment Task Force Charter Founder

Bob AZ wrote:

A trick an old-timer taught me to drill through hard steel like spring steel is to use a copper rod of the diameter you want the hole.

Mount the copper rod in your drill press and put a little plasticine (trade name for child's modelling clay in Australia) or chewing gum around the hole to make a dam and add some valve grinding paste and a little oil.

Use the copper rod to rub the valve grinding paste into the hole and keep lifting it on a regular basis to allow the removed metal to get out and fresh valve grinding paste to get in. The copper rod is soft enough to grip the abrasive particles that embed in the end.

This method works better than most people expect, and will also work for drilling glass.

Now hat I'm regarded as an old-timer, it is nice to be able to pass this on

Hope this helps, Peter

Reminded me of another use for valve grinding compound that I've used many times. If you've got a lot of very tight Philips head screws, put a little dab of the coarse compound on the Philips bit and you can put way more torque on the screw head before slipping out and ruining it. Works very well if you're stuck in a position to where you can't really put all your weight against the screw head.