Drilling aluminum

[mantisory]

Hi all. I am not a machinist by any means, but i have a (maybe) dumb question.
I have some 3/8" thick 6061 AL plate that i want to drill a 22mm hole through. Also, on the same center I'd like a 28mm hole halfway through, as the picture shows:

However, I only have limited tools - a handdrill, a drill press, etc...
Question: is it possible to do this with the tools i have, assuming i am will to spend a few bucks on bits or whatever? Would a combination of spade bits work? Also, it is not necessary to have it super accurate.
Thanks,
Byron

[Nordic]

Yep, woodwork tools should work fine, allthough I'd suggest getting metal drill bits

[jol50]

Also depends on how pretty it needs to be. A regular drill often does not cut a smooth surface, cutting oil may help.

[Nordic]

I guess a fostner bit would be better than a spade... good idea to use lubrication.

[Andrewbee]

For cutting Aluminium use methylated spirits as the lubricant. Failing that WD40 is okay.

I would recommend you use a drill press and buy (borrow) the correct metal bits. Better to have the correct tools and do a good job than try and do it for cheap and mess it up, plus, if you need the bits again for another job you will already have them. Bits are hardly expensive unless you want cobalt types or something.

Andrew

edit. MAKE SURE YOU SECURE THE ALUMINIUM BEFORE DRILLING, IF IT SPINS IT WILL CUT YOU BEFORE YOU REALIZE WHAT HAS HAPPENED AND WHEN I SAW CUT THATS IF YOU ARE LUCKY, IT WILL REMOVE AN APPENDAGE (FINGER) QUITE EASILY.

[Peter Daniel]

Fostner bit will not work in aluminum.

You can open the hole with a step drill or hole saw: http://www.mkmorse.com/holes.html

The halfway notch can be done with a rabbeting bit (on a router mounted to a table) working your way gradually, 1/16th or so at a time: http://www.routerbits.com/cgi-router...583741_4141+25

[jol50]

Oh yes, step drills work great if you can get the right size. But if your material is thicker than the step it can be a pain to open the lower part straight out. I would use a drill press and clamp it on there, otherwise stop by a machine shop and they might do it for a couple bucks at the right place. Holesaw then router it, that could work too.

[Cal Weldon]

I wonder what a milling shop would charge to do it.

[Peter Daniel]

There is actually even simpler way to do the notch. Get one of those rotary files, mount it on a drill press, adjust the depth an manually cut out the halfway opening.

As to the main hole, a propel drill bit or hole saw would be the cheapest tools, step drills are rather expensive.

Wear leather gloves as you never know what can happen

[Cal Weldon]

Peter,

That looks like a reaming tool. How do you get that to do the recess?