I sell 1" reduced shank, "Made in China" bits at work for about $7 (Canadian dollars). They will work for aluminium no problemo.
You should lightly hone the cutting lips of the drill before using it to reduce its tendency to grab the material (getting whacked in the [insert body part here] hurts!)
I wouldn't bother with drilling multiple holes before the 1". Try something like a 1/4" or so, then go straight to 1". Drilling intermediate holes will cause the drill to try and screw itself into your material (because aluminium is so soft) and could result in a shattered bit or other fun situations.
Also, don't be afraid to cram the drill into the aluminium. This will prevent chatter and make your life slightly more exciting and certainly more productive. The slowest RPM on your drill press is probably good. If it's cutting really nicely, you can start going up until you can't feed fast enough to prevent chatter. For a 1" bit, you *could* run it at about 1200 RPM, but you'd have a hang of a time feeding by hand...
Cutting fluid is a must or else you will get aluminium welded to the cutting lips of the drill.
I wouldn't be quite so quick to condemn the advice from the Sears guy. The hole saw should be fine if he uses it correctly. Which means cutting fluid / lubricant, backing out periodically to clear chips, and possibly drilling relief holes for the chips.
The Silver & Deming bit should work, although the material is a bit on the thin side for that diameter.
I've done a lot of holes that I didn't have the right size bit for by using a homemade boring bar in the drill press. The key there, as with a flycutter, is to have a backup piece under the workpiece with the pilot hole through both of them, so that the backup piece supports the end of the boring bar even as it breaks through the workpiece.
Best method will vary with quantity, finish and accuracy needed, though.
Hole saws don't *always* clog -- if you prepare properly.
1) Take the workpiece, and drill a smaller hole -- perhaps 1/4" or 3/16" just inside the line of the hole you wish to cut with the hole saw. This provides a place for the chips to exit which build up between the teeth, and otherwise support the saw teeth clear of the workpiece.
2) Set the drill press speed appropriately for the size of the hole you intend to make. With 1", and aiming for 80 SFM (I should look that up to make sure that it is right) you would need about 305 RPM (or slower).
You never said how fast the drill press spindle was turning. Slow is good for a hole saw.
O.K. Looking at the tables in _Machinery's Handbook_, the slowest speed for *turning* an aluminum alloy (and we don't know what alloy you have) would be 40 SFM. That is probably a safe (if conservative) one for a lubricated sharp hole saw with one or more chip clearance holes as described above, so that would be about 150 RPM on the drill press spindle for the 1" hole saw. For many alloys you could get away with higher speeds, but this one should do for everyone.
3) Use lubrication -- *don't* cut dry. You have already gotten advice to use kerosene. If you can't find that easily, that is one of the things that a spray can of WD-40 *does* happen to be good for. :-) Keep withdrawing the saw, and spritzing the slot and the teeth with WD-40. That should make it cut a lot faster, assuming that you have the chip clearance holes described above in place.
4) As already advised -- clamp it down firmly. And to avoid screwing up the table, put a block of wood under it to support it, yet to give something which is easier to machine away than the drill press' table.
You have already read elsewhere in the thread that the name you are looking for is "Silver & Demming" drills (reduced shank drills).
For other ways to make 1" holes, the best would be a boring head in a milling machine -- but you don't have that.
1/4" is too thick to use a Greenlee chassiss punch, though 1/8" would work (probably barely). For that, all you need is about a 5/16" hole in preparation for the drawscrew. But they are slow, and take a good vise to hold the punch from rotating, and a good wrench on the head of the drawscrew. Nicer are the drawscrews with the ball bearing thrust assembly.
You could also use something called a "Roto-Bor" in a drill press, but I think that they have not been made for many years now.
Next time..drill a couple holes inside but touching the cut line, for the chips to fall through. Then use plenty of kerosene for a cutting oil, and turn it slow.
Gunner
"In my humble opinion, the petty carping levied against Bush by the Democrats proves again, it is better to have your eye plucked out by an eagle than to be nibbled to death by ducks." - Norman Liebmann
I have, in a pinch, and not for too many holes, used a fostner bit from my woodworking tools to drill very clean holse in Al. Very slow drill speed and some coolant. Not the best but it works - the bits are cheap too
You may have gotten good advice on this already, but if I needed accurate 1" holes in aluminium and only had a drill press, I would get a 31/32" Silver and Deming style drill, along with a few smaller sized including 3/4". I would step-drill up to 3/4", then go to 31/32". I would use a fairly low speed on the drill press, no more than 500 rpm for sure. Then I would ream to 1". If your need for accuracy is less that that, you could go to a 1" drill after the 31/32". If your need for accuracy is actually fairly low, I would drill to 1/2", then 3/4" then directly to 1".
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