Drilling Aluminium

The cutting face, or flute, which forms the cutting edge rake angle, is what should be stoned. Stoning the edge to reduce the angle will reduce the inclination to hog. If you're confused what should be stoned, you'd be better off to seek assistance so you don't end up screwing up the drill. If you feel you understand, don't go negative, and try to keep the alteration of each side the same. You might have better luck with a wheel instead of a stone, assuming you have good hand grinding skills.

It likely goes without saying that this job would be far better done under controlled conditions (not by hand) to insure you don't wallow out the holes, nor lose relative position. That being said, it can be done by hand, it just offers more risks, as you've discovered.

Harold

First off, put some lube in there. Secondly, don't push. Keep a firm grip on the drill so that it doesn't want to get ahead of you or away. Spin it up fast before you enter the hole and don't push when it's in a spot where it wants to bind up. Let the drill bit clip off the burr that comes from getting too big a bite then go in easy. If you can step up in size to where you want to be you'll get a good clean hole with less binding as will happen from a single drill bit.

That's a pretty big hole to try and drill by hand because you are feeling the torque caused by those tips as they cut the aluminum. Unless you have 19" biceps and press 500 pounds, I doubt the result will be very pretty. As for "stoning" the bit, IMO that sounds like advice from someone who spends a lot of time stoned. Without some experience, anything you do to the modify bit is likely to make it worse not better.

Forget the air drill. Take the wheels off and drill them on a drill press with plenty of lube and some clamps.

M> Hi All

Stop!

Perhaps you should consider your options. If each wheel has 5 lug holes and you bugger one up how much has this exercise in frugality cost you? Or worse, consider if you have wheels that are buggered and you get into a wreck?

Take the stinking wheels to a machine shop and let them drill out your holes.

About the only way I would attempt this with a hand drill is to make a special bit with a 5/8" pilot and one cutting lip like a unibit. Also I would think an air drill is too fast, an electric might be better.

...

What a wonderful walk down memory lane. Went "up" to index and seen lots of posts by "Teenut", Robert Bastow. May he rest in piece. I didn't see my personal favorite "Teenut" post, the six million dollar bionic drill sharpener, or how to hand sharpen a drill bit.

Karl

Dare I suggest using an expandable hand reamer? It will do a neat job without the risk of 'bellmouthing' the holes. Bugs

I didnt read it all-standard drill modification for drilling brass applies in this kind of case is all.

When your hand drilling to enlarge a hole only a tad bit then your positive rake due to the flute helix is mostly a hindrance...better method would be to use a straight shank reamer or core drill.

The "stoning" is to reduce the angle of the tip of the drill so that when it grabs (and it WILL) it won't screw itself so far into the hole that you can't get it out easily. You also want to stone the edge off of the sides past about the first tenth of an inch of the flutes so that they won't grab in the bore. It would be a lot better to put the wheel in a drillpress or, better yet, a mill to do the drilling as you will be keeping the drill bit straight and can control the cutting rate a lot better. Also, you can use a lower speed which will help control things a lot better than a bouncy air drill which will kick sideways as the drill bit sinks into the metal. Considering the amount of material that you need to remove, you might also want to consider using a reamer instead for this job as you're taking less than 1mm of material off the wall of the hole.

-- Why isn't there an Ozone Hole at the NORTH Pole?

Take the wheels off and get an appropriately sized bridge reamer. Get some other kind of drill motor that goes slower. You really need to hold things still and in alignment. Otherwise you will probably be sorry about the result.

Pete Stanaitis

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M> Hi All

Hi All

I need to enlarge the mounting holes in a set of cast aluminium wheels from

I'm finding the drill is grabbing quite badly in the soft aluminium. I found in a search that you can 'stone' the drill to stop this happening, or at least make it better. I'm curious about which part of the drill should get this treatment though. The cutting lips, or ???

Thanks, Trev.

It sounds like might be trying to adapt a set a wheels to a different hub type. Be careful here, the center hole of the wheel is what locates it accurately on the hub, not the wheel studs, they just clamp the wheel to the hub. You need to make sure that the hub center is the same diameter on both the new hub and the old hub or these wheels will shake and vibrate and eventually come off.

Paul T.

Correction, I had meant to say "straight flute"...not "straight shank"...