Bought a Unibit yesterday..

[chptunes]

Great tool.  It's a bit costly, but very nice when drilling die-cast enclosures.  I think mine has 12 stepped sizes.. it drills very round holes.

Wish I'd bought one sooner.. beats changing multiple bits and filing/deburring.

[KazooMan]

Yep, they are great for drilling enclosures.  Even the cheap ones you can get at Harbor Freight will do a good job on the aluminum.  One thing to watch for is any build up of aluminum on the inner edge of the cutting surface.  If you leave it on the bit you can generate quite a bit of heat when drilling and you may dull the edges.  You can pick the residue off with a small screw driver or a utility knife.

[rousejeremy]

Spray a little WD40 on the bit and it will fly right through the aluminum without too much aluminum building up in the cutting surface.

[chptunes]

Thanks for the tips...

[pappasmurfsharem]

  Yeah I bought the harbor freight set of 3 for 12$

The most useful one with nearly every size needed for a stomp box is now useless and I seem to be unable to scrape off the aluminum residue after about 5 boxes.  oks almost fused now.

I'll definitely have to give WD40 a try when I buy a replacement set

[chromesphere]

I use a chizel and scrap along the cutting surface.  It also removes any burs on the drill bit.  Ill have to try a bit of wd40 as well!  I have drilled, countless, enclosures with my current set (australia -> bunnings 3 piece set)
Paul

[R.G.]

There are customized aluminum cutting fluids that machining pros use, but kerosene works - and WD40 is part kerosene. Swiping the cutting edges with a wax candle or parafine (US usage: translucent wax harder than beeswax) works well too. So does almost any oil, like 3-in-1, motor oil, etc.. Almost any hydrocarbon on the edges is better than cutting dry.

If you have a built up edge, push the buildup off with something softer than the bit. Hardened tools like files and chisels may chip the cutting edge. Brass is a good one. A hardwood stick may work if you have lubricated it before drilling.