Forum Index » Make Your Own Gear » Having trouble drilling Aluminum


Display Avatars Sort By:
Tad Englund
(bestbuilder) - F - MLife

Locale: Pacific Northwest
Having trouble drilling Aluminum on 04/14/2013 11:27:53 MDT Print View

I was given a sheet of 1/8" aluminum (don't know the make up) and I am using it for snow saws.
The problem is when trying to drill the teeth for the saw I can't get the 3/8" drill bit to fully penetrate the saw blade. It worked on the first couple of holes but then the bit of the drill press would bind and stop turning. I changed bits and the other bit did far worst.

Is there a special bit for some aluminum's? I didn't have this trouble with the last saws I made (more than a few years ago).

Edited by bestbuilder on 04/14/2013 11:29:16 MDT.

David Scheidt
(dscheidt) - F
Re: Having trouble drilling Aluminum on 04/14/2013 12:39:50 MDT Print View

sharp bits, slow speed, slow feed, use a cutting fluid. Most aluminum is easy to drill holes in.

jerry adams
(retiredjerry) - MLife

Locale: Oregon and Washington
Re: Having trouble drilling Aluminum on 04/14/2013 13:19:57 MDT Print View

Clamp piece of wood on both sides, drill through wood, through aluminum?

That's good for sheet metal

Hoot Filsinger
(filsinger) - MLife

Locale: Pacific Northwest
Re: Having trouble drilling Aluminum on 04/14/2013 13:21:03 MDT Print View

Tad,

Your drill chuck spindle may be lose in your drill press. Most are easy to fix. Check out this video on YouTube for procedures.

http://youtu.be/KbI_7IHAsyw

Elliott Wolin
(ewolin) - MLife

Locale: Hampton Roads, Virginia
RE: Having trouble drilling Aluminum on 04/14/2013 15:35:54 MDT Print View

There are special bits for drilling sheet metal, the end of the bit is almost perpendicular to the shaft of the bit, very shallow cutting angle. They almost look like an end mill. Sometimes machinist make them out of regular bits. If you have a lot of drilling you might look for them, otherwise clamp well, oil, slow feed, as others have mentioned.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Having trouble drilling Aluminum on 04/14/2013 15:42:08 MDT Print View

Hi Tad

?????????????????

If you said you were having trouble drilling high tensile steel I could understand it, but aluminium, of any sort?????

I think you must have a problem with either the chuck jamming open or the pulley belt slipping. Even a dull drill bit should go through.

Question: does the drill spindle also stop, or does the bit slip in the chuck?

Cheers

Roger Dodger
(RogerDodger) - F

Locale: Wess Siide
Re: Re: Having trouble drilling Aluminum on 04/14/2013 18:35:35 MDT Print View

There is a possibility that it is not AL or not pure AL. Trying running a magnet,
Aluminum is non-magnetic.

James Marco
(jamesdmarco) - MLife

Locale: Finger Lakes
Re: Having trouble drilling Aluminum on 04/14/2013 19:18:17 MDT Print View

I suspect your drill press is not running correctly, as others have said, if the bit is up and just stopping.

If you have a mill press, often the chuck will use a morse taper, #1 or #2. On occasion, this may get a bit rusty, especially if it has been unused for a while. Clean and reseat it. They, the male/female seats, *should* be fairly bright with no oil on them (well, maybe a light rustproofing film.)

This *can* slip even if the motor and pully's are functioning normally. You may need to clean the rust and reseat it. I didn't see where this was mentioned.

Aluminum is a very sticky metal. Often, it will build up around a less than perfectly sharp bit. The heat will actually fuse shavings to the sides of the bit making the bit VERY difficult to penetrate to any depth. The metal will expand with heat, then contract around the bit, rather like a vise. Normally these are both symptoms of a dull bit and/or too high of a turning speed. Slower is often better. Pressure can do this, too. Really a bit of an art.

The first 1/4" may be worn a little and the upper portions are still the correct diameter, also. This has happened with bits that have been resharpened 8-9 times, too. With deeper cuts, you end up cutting a LOT of metal. Old belts sometimes develop a glaze and slip very easily. Take it off and try scrubbing it with some alcohol and a fine wire brush. It might need replacing if it is really bad and has notches in it. It's very hard to regulate speed and pressure with a bad belt/inconsistent belt pressure. Check the tension, while I am thinking about it. Aluminum should cut easily but it has some quirks. Like brass, it will often dimple around a hole slightly anyway. (Brass is not quite as sticky, though.)

Oil, or, cutting fluid (often soda water) will help, but was mentioned.

Not real complicated, the splined shaft should not be dropping below the seat, of course. And the motor should spin. Not much else to go wrong and freeze up.

Tad Englund
(bestbuilder) - F - MLife

Locale: Pacific Northwest
Re: Re: Having trouble drilling Aluminum on 04/15/2013 10:20:15 MDT Print View

Thanks for all the info. Roger, I too was surprised that The drill had trouble, never did this before.
I'm using a Delta
Drill Press

Here is what the belt looks like (I tried it at 2400 RPM, 3100 RPM, 1750 RPM) the belt is about 10 years with very minimal use
drill belt

Here are the drill bits I useddrill bit 2drill bit 1

Here is what I'm trying to drill, see the one with the elongated hole, that is what the last two did also. Could it be that I'm trying to drill a 2/3 hole in the side of the blade and the bit is just binding?saw blade 1

Edited by bestbuilder on 04/15/2013 10:21:29 MDT.

Kevin Beeden
(captain_paranoia) - F

Locale: UK
Edge drilling on 04/15/2013 11:20:04 MDT Print View

I think you may have identified the problem; trying to drill a partial hole at the edge.

I'd be tempted to drill complete holes and then trim (guillotine) the edge off to get the partial holes you want. It will waste a bit of metal...

How are you clamping the workpiece? It looks like it's drifting, because I don't see those big bits moving much (although they're pretty long).

Tad Englund
(bestbuilder) - F - MLife

Locale: Pacific Northwest
Re: Edge drilling on 04/15/2013 11:45:41 MDT Print View

Thanks Kevin, I am free handing it (no clamps- trying to save time).

Any Ideas on how to do it with out drilling a full hole? I don't want to make the blades to narrow

Dustin Short
(upalachango) - MLife
Re: Re: Edge drilling on 04/15/2013 12:27:59 MDT Print View

You're going to have to clamp for sure otherwise you'll get too much chattering and vibration free hand. I'm not sure but I'd assume you'd also have to lower the rpm as much as possible (similar to milling operations).

brent driggers
(cadyak) - MLife

Locale: southwest georgia
edge drilling on 04/15/2013 14:15:58 MDT Print View

that is probably the issue.
If you have enough of the metal left to try it again you can move your hole over until it clears the edge and then cut the metal through the hole. I use that technique to get this type of top edge on my stainless steel wood stoves.

sp600 3

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Re: Re: Having trouble drilling Aluminum on 04/15/2013 18:16:10 MDT Print View

Hi Tad

Fine drill press, OK drill bits. Although stub drill bits would be better.

WRONG place to drill hole however. I would never attempt to drill a hole that close to the edge of sheet metal. It WILL go wrong. The tapered point on the drill means it relies on having metal ALL around it to stay centred. If the drill bit is unsupported on one side the metal will walk.

You have two ways to do this. The first is to drill the row of holes with about 5 mm of untouched metal left on the outside edge of the saw. Then, with all holes made, you cut off the excess along the edge. A good guillotine is best for this, but tin snips can be used. So the blank you start with has to be wider than you want.

The second method uses a square-ended 2-flute slot drill or milling cutter. This lets you 'drill' right on the edge. However, for this you MUST have the job firmly clamped down for every hole. Even so, it is a bit of a chancy business, and is not recommended.

I suggest you start again. Make the blank over-size. Fix a guide to the table for the back of the saw to press against. Drill all holes, then cut off the XS.

Cheers

Edited by rcaffin on 04/15/2013 18:16:56 MDT.

Bob Gross
(--B.G.--) - F

Locale: Silicon Valley
Re: Re: Re: Re: Having trouble drilling Aluminum on 04/15/2013 18:27:26 MDT Print View

I'm not trying to break up a perfectly good MYOG project, but I guess you know that these aluminum snow saws are commercially available. The teeth even have an alternating crosscut pattern. With the MYOG version, I think you will end up with rip pattern teeth, even if it works.

--B.G.--

Craig W.
(xnomanx) - F - M
Re: Re: Re: Re: Re: Having trouble drilling Aluminum on 04/15/2013 18:34:20 MDT Print View

You might also try clamping the aluminum between two ~1/2" pieces of plywood. The wood can help keep everything aligned, your bit from slipping over the edge, and prevent the metal from deforming in the process.

jerry adams
(retiredjerry) - MLife

Locale: Oregon and Washington
Re: edge drilling on 04/15/2013 18:59:27 MDT Print View

Take a piece of wood on both sides and clamp it all together. Then drill through wood, metal, wood. The wood will keep the drill centered. Doesn't matter you're on edge of metal.

(This may or may not work)

oh - Craig beat me to it - except I mentioned it above too : )

Edited by retiredjerry on 04/15/2013 19:01:26 MDT.

Samuel C. Farrington
(scfhome) - M

Locale: Chocorua NH, USA
bits on 04/15/2013 20:16:16 MDT Print View

The top one looks very dull and worn at the point, and the only ones I've ever seen that look like the bottom one were for wood, not metal.
Try a fresh HSS bit.
You can also get HSS Forstner bits in 3/8 that might work better in this application.

The work should also be tightly clamped to wood underneath, and you'll have to move the underlayment a little and reclamp for each hole to there is solid wood underneath each time.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Alternate approach on 04/15/2013 22:16:16 MDT Print View

Sometimes I get too close to the problem.

Hunt around and find a cheap hole punch for sheet metal. This WILL work just fine at the edge of sheet metal. eBay is the obvious place to go. Try
'1 Ton Aviation Power Punch Kit Sheet Metal Hole Puncher Compound Leverage Tool'
as a perfect example - but note limited hole size, up to 9/32".
Q-max punches also wortk very well.

Do NOT try to use a punch designed for paper! It will not work.

Cheers

Tad Englund
(bestbuilder) - F - MLife

Locale: Pacific Northwest
Re: Alternate approach on 04/15/2013 23:17:15 MDT Print View

Roger, will the unit you recommended punch through 1/8" aluminum?

That looks a lot easier then clamping wood on both sides for each hole x 12 holes per saw x 4 saws.

I figured out that on my old saws I made I did drill first then cut. I was in to big a hurry this time, free piece of metal and trying to get as many out of the sheet as I could.

Bob, I have used the "commercial" saws and they are a nice toys- they are way too small to make a correct sized block for igloos, you need at least an 18" blade. There is only one on the market now that I've seen that come close and at $55, I'll stay with my MYOG. Plus with the Scouts as the main users, I need something that I don't have to keep an eye on while in use.