I use a Makita Compound Mitre Saw. The instructions say you can do this. Just do it slowly! An angle grinder may well melt the aluminium as it spins so fast. If you were in Sydney I'd be happy to cut it for you. See if you know anyone with a similar saw.Clear skies,Shane
Like the man said, never use an angle grinder for soft materials like aluminium. It will jam in the cut and either shatter the blade or fly back at you. Either way the consequences could be nasty.
Cutting by hand with a hacksaw needs a coarse toothed blade 12-10 teeth per inch and kero for lubricant. Petroleum is not recomended as the heat generated by the saw could ignite it.
If you are energetic take the hacksaw route. If not, sidle up to an alloy joinery sho[, the type that make windows etc, you may be able to convince someone to cut it for you.
I used to do light weight aluminium fabrication for a number of years.
We used beeswax to lube the blades.
If you have a straight edge on the piece you are cutting, that you can butt up against the back of the saw bench, use the mitre saw, otherwise use a hacksaw. Mark your cut with masking tape because pencil can wipe off.
I'd keep it down to 400rpm at most, otherwise you get a bit of "chatter and the csink looks rough. Yep, lubricate with kero, gives a better finish and lengthens the life of the countersink bit.
Also when countersinking, I have a "single flute" countersink. A normal "woodworking" one with 4 flutes will often leave a very rough finish, especially if the speed is too high. Generally with ali, slow is better than fast as it has a tendancy to "grab"...not as bad as brass though!
Is it ok to cut aluminium with an angle grinder or should I use a hack saw? I'm wondering if it will clog up the cutting disc.
I'm cutting up a Vixen-style dovetail into shorter segments and want to do a neat job, but I'm also curious about aluminium cutting in general.
Hi,
Other posters have covered the most of main recommendations. There are a few issues at work:
- Clogging a cylindrical grinding wheel with aluminium or other non-ferrous material can cause the surface layers of the wheel to disintegrate and fly around. The danger is not so acute with an angle grinder disk which usually has embedded fabric reinforcement, but it still isn't recommended.
- Using a compound mitre saw with a blade which is normally intended for wood will certainly work, but you must take it very very carefully and not press the progress of the cut at all. This is because the teeth of such a blade have positive rake angles and can 'hook' and catch the metal, jerking it forcibly away. Something usually shatters, like the carbide tooth inserts on the blade. You can buy aluminium saw cutting blades from Bunnings etc and these have different cutting tooth angles. At the very least try to arrange 2 point mechanical clamping of the job with a G-clamp or similar.
- Aluminium dust is injurious to the lungs, and can also form an explosive mixture with the ferric oxide dust produced by grinding steel. Explosions in home workshops from such a mixture of grinding residues are rare, but not unknown.
- All in all a hacksaw is recommended as our colleagues have suggested.
I've always clamped the aluminium to a piece of timber when cutting with a drop-saw - especially with Al angle - place it over a block of timber, helps to brace it while it cuts too....
Thanks again for all the info guys. I got the first cut I needed done at a local windows place, but I don't want to bug them again.
Phil the jigsaw sounds good (since I have one). What type of blade would you recommend? From the other posts I gather the jigsaw would be run at a slow speed?
the aluminium oxide that forms the skin on aluminium will clog.
Hi David,
'Fraid not, the aluminium oxide layer is very thin, about 0.05 mm max, and it is not this which clogs the teeth of a file or blade, but the parent metal. Aluminum oxide is also known as carborundum, and is not soft but very hard and brittle, and is widely used as an abrasive grit in grinding wheels and papers. Ever see a white cylindrical grinding wheel? Aluminium oxide.
All the same you have posted very good advice, a jigsaw is a great idea, very safe, and I would use a blade about 4mm pitch, or about 6 tpi. Generally you would use a coarse blade in softer metals, and don't force the cut.
Bandsaws have to have the correct settings and blades as a machine tool class, because otherwise they will throw the blade.
I once had a terrible time with a bandsaw trying to saw up a radial car tyre, I could not get the right combination, and it threw the blade persistently until we sped it right up and took the cut very slow.
nothing will give a better cut than a drop saw with a proper aluminum cutting disc, i used to cut a lot of aluminum extrusion with one, very smooth almost polished cut but the blades are expensive. i always used lanolin spray as lubricant.
a rough cut will take a long time to clean up with a file or the like and it will never look professional (before we got the cut off disc i used an electric hacksaw but the cuts looked horrible)
The pst now has its own dovetail. With a cheap mount left out on the back veranda the dovetail minimizes set-up time. For countersinking a mulit-fluted bit at low speed seemed to work best.
