Drilling angular holes in hardened steel?

Question

I have to drill a hole in the side of a hardened steel cylinder.

Let's say I have a solid hardened steel cylinder on a datum axis A with one face mated to a datum plane B. Here's a rough portrayal of the datums:

B

|

|--------------------A

|

Now let's say I cut out a cone from the face that was constrained to B. The base diameter of the cone is the same as that of the cylinder, and the total angle of the cone at its point is, say, 40 degrees. The cylinder now looks something like this:

\**********I

/_______|

My design requires me to get a hole of around 1/8" diameter into the side of the cylinder placed as close as possible to plane B while not going within 1/4" of the surface of the cone. It should be drilled blind up to the center of the cylinder. I'm a sophomore in college, I'm not yet familiar with machining and manufacturing. So my question is, how steep of an angle can you drill into hardened steel, if you can even drill angles at all?

Answer 1

I realize this might not help you. I'm not an engineer. I'm a hobbyist. I'm a computer guy. But I like to make things.

I'm goal oriented. So I read up on things and then jump in and try things out hands on. I'm probably lucky I'm not dead yet. You never forget that smell of burnt meat when you realize you just singed off your own finger prints on a piece of hot steel.

So remember to wear gloves and safety glasses.

You can drill holes in hardened steel. You can drill them at any angle.

You need the right drill bit or grinding bit. A drill press and a drill press vise set at the angle you want to drill. You put some oil on the bit to help keep the heat down. You have to go slow. You need to stop and put water on the piece every so often to keep the heat from changing the metal. If you can get a machine that sprays the oil and water on the piece, thats even better. But I only see them at the factory where I work.

I didn't really understand the thing about heat until I started breaking things.

Thanks for asking this.

I'm really curious to see what professional machinists have to say.

I love this stuff.