Drilling aluminum

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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:
An externally hosted image should be here but it was not working when we last tested it.

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
 
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.
 
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.
 
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 ;)
 

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As others have noted, you might need different techniques to make a pretty hole than an ugly one.

An ugly hole like this could be created with a hole saw. Drill the pilot hole, then halfway through with the smaller size saw bit, then all the way through with the bigger one. Because of the extreme kerf/set of the teeth, those things tend to leave a pretty rough surface.

If it were me, I'd drill it out a little undersize with a hole saw. Then, using a rabbeting bit in a router and a metal template (which you'll have to make) as a guide, enlarge the hole. A small sanding drum chucked into the drill press can be used to clean it up if need be.

This will be about as good as you can do in a small shop without any kind of milling capability. You can get it to the point where it's pretty clean, as for a recessed volume knob, for example, but it won't have thise nice parallel mill marks that you would get on a mill with a fly cutter. That kind of precision is pretty much impossible on a drill press unless you've got a custom-made cutting tool, and even then...

--Buckapound
 
I did that opening with a hole saw. IIRC I used sanding drum to smooth it out a bit, but all in all it came out pretty nice anyway, considering existing anodizing: http://www.diyaudio.com/forums/showthread.php?postid=493493#post493493 The knob was done by hand too, on a drill press using disc grinder.

In a previous suggestion, I believe the large size saw bit should be used first (halfway through), then drill all the way through with smaller one.
 

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