Thread: Trying to drill Very hard metal

Get yourself a brand new tungsten carbide (masonry) bit.
Use slow (<200 rpm) speed and lots of lube.
Ideally you need a high pressure such as you would get via a drill press and use very steady pressure.

That's exactly what I was going to say.......

A ball headed diamond burr will do it.

It will be very slow, but it will go through it, no problem.

The other option is to anneal it, drill, then reheat and quench to reharden.

Rob

It looks to me that only a small dia hole would be required and the masonry bit would need to be sharpened
as per a normal steel cutting drill bit to drill it, a standard masonry drill bit doesn't really drill as such, it more
chisels with the impact from the drill.
Why not weld something to it that you can feed the wire through, or buy/make a sump plug out of softer
material.

What about a solid carbide drill bit of the appropriate size. I'm guessing you want something like a 2mm hole?

Solid Carbide Drill BIT 2 0mm Diameter Drilling | eBay

I'd take a bit of time with getting a nice rigid setup, as small diameter carbide drills break easily.

Regards
Ray

Probably case hardened so the head can withstand the constant doing up and undoing without rounding it off...

Originally Posted by woodfast

I am trying to drill a sump plug have tried using Sutton cobalt drills all they did make a small mark on the plug what else could I try to drill this through so it can be wired as it's on a aircraft motor

Braze or weld a tab to it?

what bob l said it works.

Try using electric arc pitting or boring

Years ago I wanted to make a 1.5mm hole through a 4.0mm ball bearing without annealing it, I made an EDM more as an excercise to see if it was achievable. Worked fine.
Now to try & add a pic.

If it is case hardened a masonry bit will work till you get through the skin, then it will dig into the softer metal and that's the end of the bit, then use an ordinary twist drill till you reach the hardness on the other side then change to another masonry bit.
DAMHIK
Regards

I was surprised that the cobalt drill didn't touch it... then I read "Sutton". I have standard HSS drills that cut through 304 and 316 cleaner than Sutton cobalt. And don't go blunt in the process. Unless your drills were already blunt in the first place...

Try getting some decent branded cobalt drills like Dormer or SKF from abroad. Or some carbide tipped twist drills designed for hardened steels (not masonery bits). McJing sell these: look about a quarter of the way down the page. Steady pressure, speed and feed rated for the drill bit material and diameter; and lots of lubricant/cooling/both.

Saying that though; I stiil think you're going to struggle to drill it in it's present form. Are their no markings to indicate the grade of steel used? If you can identify the steel you can soften it, drill it, and re-harden + temper it using carefully controlled heating as Nearnexus says.

Hi tinkera,
you'd better explain the workings of that piece of equipment in a bit more detail - please.
You have my full attention!

Hi Joe, I thought that might get some response, Since posting I have found about 8 more pics, I will try to post details with pics, but not much time at the moment, (Lake Goldsmith is calling) Also I will print the pics & it could make a good conversation piece when I'm in Bendigo in a couple of weeks. Apart from the useable things like "G" clamps, I tossed everything else in a cardboard box, could reassemble easily.
Ian.