Thread: Cutting Aluminium Extrusions

We used kero as a cutting lubricant for aluminium when I use to work for an engineer firm, much better then the wax

As for cleaning the blade

The correct lubicant for cutting/machining aluminium is indeed, kerosene. This actually reacts with the metal, cant remember in what way, but you can tell it does by the aroma produced when cutting. Clean the blade thouroughly and use the kero for cutting. To remove the aluminium from the blade, you could try soaking the blade in a weak solution of caustic soda. This stuff disolves the metal while you watch. Do this outside as lots hydrogen gas is formed. The caustic soda wont hurt the saw blade but it can eventually etch it after many hours if it is a strong solution.

If you want to get a great finish on an aluminium frame or strip, drop it in a stronger solution of caustic soda for about a minute. The result is a beautiful silky surface that can be dyed somehow. Dont leave it for more than a minute or it will disapear. Wash it with lots of water and dry the part. It looks great and is easy to do. I think the surface is also slightly hardened in the process similar to annodizing.

Kody

I have used a drop saw on aluminium with success on components ranging from tubing to 75 x 25mm bar.

When cutting aluminium you need to be firm with the cut pressure or very very light. It seems to depend on what you are cutting. Somewhere in between and the blade gums up.

I use wax as a lubricant and it works fine. Sometimes a squirt of WD40 on the material helps as well.

I would be a little careful using kerosene near a drop saw, kerosene is afterall a combustible liquid with a flash point around 40 degrees and easily exceeded reached when cutting amuminium. That coupled with the motor producing small sparks could put you in an interesting situation.

Warren

Just my two bobs worth...and I'll probably get howled down for suggesting this.......

I cut a bit a fair bit of Al rod - mostly between 5 to 80mm diameter stuff......I don't possess a drop or band saw and got sick of hack sawing and using various blades in the straight and angle grinders - they all clog up and don't work well........to get relatively square and angle/ mitre cuts to length for mounting up, I now use a tc tipped blade in my bench saw and take it slow feed for the larger stuff ...dry cut, no lube..same for angle cuts....I might add a proviso here that my bench saw is pretty big and the motor well insulated and clutched because sometimes the cut will bind and you need to withdraw and re-feed etc....same as with wood....like everything, you need to take it slow and see what works best with what you have at hand......

To dress and work the aluminium in the lathe I use metho or kero as previous posters mentioned......for me, metho works better as it evaporates with no residue.........you use a bit more but it keeps the mozzies away .have found with Al you still end up with some crud on the HSS tool tip no matter what lube you use, only way to avoid that is by altering the tip shape and angles..chip breakers are even worse for me.....it is a trade off with the standard of finish or type of cut you're after and the composition of the Al.

The cutting speed of my saw blade is similar to that required for 2011 and the issue with using a saw blade is the set on the teeth.......tc tipped blades are not usually set as much so there is less rip.

I would certainly not recommend this method of cutting to work length with just any bench saw....but tc tipped blades will cut just about anything if you need - due care and diligence!!!!....the swarf is the problem and as the blade is usually mounted over the motor in bench saws, you have to know what your doing....sawdust is more forgiving than metal swarf around electric motors!!!

I now only work with Al 2011 IRD and the above method on 2011 seems to work OK for me.......I picked up a copy of the spec chart from Capral Aluminium last week on the various Aluminium Alloy IRD chemical compositions - which ones they recommended for turning etc...it's basic stuff but handy for knowing what they have - can post it if anyone's interested.........

Hope that helps...Lee

For the past 5 years I have worked for an engineering company and one of my duties is to daily cut 6.5m aluminum window extrusion in both large & small section to lengths for window & door installers .
No lubrication is used and I use a 110 tooth TCT aluminum saw blade. The cuts are nice and clean. I have encountered no problems with blade clogging etc.

i have a festool kapex drop saw i use wax and alter the speed of the machine but i use a timber scrap behind thin angle as it still can grab on short cuts because it does not go from fence to fence i hate the wax build up in the saw any ideas how to remove it?
i remove ali stuck in the blade by cutting a few scraps of hard wood

I agree with Mulgabill.

Your blade doesn't look like like a dedicated aluminum blade. I have two blades for alum, and both are negative rake, with many plenty teeth. No lubricant is required, and cuts are very neat. I also agree that straight kero is the lube of choice for machining aluminum in a lathe or mill, but not required for light stock cut off in a drop saw.

Inox is also great for cutting aluminium. Very good for tapping.

bollie7

All interesting helpful advice. Thank you

Originally Posted by Fossil

IYour blade doesn't look like like a dedicated aluminum blade

It is a Bosch Al Blade, not that it means it is a good one though. I have a couple of other Al blades, I'll have to compare them.

I was also wondering about the speed, perhaps my little crappy cheap drop saw is too fast, or too slow.

Looking at your pic it looks like the blade is the wrong way around. Is the pic taken looking at the front of the saw as if you were going to use it?
bollie7

It isn't just the # of teeth that make a dedicated aluminum blade. Both my ali blades have what's called "chipper teeth" from memory. Every second tooth has 45 degree bevels cut from the each corner at the top of the tooth. I tried to take a piccy, but my battery is dead.

The blade you have will cut aluminum at a pinch, but it is not a dedicated aluminum blade. By the way...... my aluminium blades don't cut timber well at all.

I have cut a lot of aluminum and never had a problem, but I always
used a metal cutting band saw.

Like:

Originally Posted by bollie7

Looking at your pic it looks like the blade is the wrong way around. Is the pic taken looking at the front of the saw as if you were going to use it?
bollie7

That's what I thought. I'm pretty sure that blade is back to front Neil, which would account for the slag and the rough finish.

I used to make aluminium windows and flyscreens and all we used was the TCT saw blade that came with the drop saw. No lubricant. Perfectly clean cuts in any thickness.

I agree with Silent and Bollie. That's the first thing i noticed but only because i tried to put a negative rake Aluminium blade on my drop saw on the weekend. I put it on with the writing on the blade facing out as usual but noticed that the teeth were facing the wrong way. I had to reverse it so that the writing was facing the inside of the guard. Looks like you have done the same thing.

(I ended up having to use the normal wood blade, because i didn't have the correct arbour reducing washers on hand, and it cut the aluminium mitre track beautifully. )