A Simple Method to Cut Aluminum Extrusion

This instructable describes how to use a miter saw to cut aluminum extrusion.

This is not meant to be a exhaustive survey of methods for cutting aluminum extrusion, it is simply a description of the method we use.

Cutting metal with power tools is dangerous and should be attempted only if you know what you are doing. So proceed at your own peril.

There is a lot of information available on the internet and you should try and read it all to help you decide if this method is right for you.

Lastly, wear safety equipment. Ok, let me say it again, WEAR SAFTY EQUIPMENT. At a minimum, a good pair of safety glasses, some ear protection and a face mask. A full face shield is not a bad idea either. There is going to be a lot of little chips of aluminum flying around and they WILL NOT go where you expect them too. They will go everywhere. The "standard" dust collection systems are not well suited to this type of material.

An electric miter saw.

A saw blade for Aluminum and Non Ferrous Metals

https://www.amazon.com/gp/product/B0012YMVBE/

Install the non Ferris cutting blade on the saw. Make sure you true the blade. (We have a cheep miter saw dedicated to cutting aluminum so as to not have to do this step every time we do a cut.)

Set the saw up in a clean, open, area with enough open space to move freely around the saw. For large pieces you may want to set the saw up on the floor. Connect the saw to a shop vac or other dust collection system. Do not plug the saw in.

If you like to sweep, use a shop vacuum and have a large collection of different size brooms you feel the need to exercise, you can ignore this step. For the rest of us, pay attention. Cutting aluminum is messy. If you have a vacuum attached to your miter saw exhaust port, it will not do much. The chips will go everywhere. They are sharp and they conduct electricity. The picture above is from a single cut of an 8020 series 10 extrusion. This is what was left inside the beam. the rest was scattered around the floor.

Improvising a dust collector will make your life easier. It can be improvised with anything. For large projects, we hang up tarps a couple of feet from the saw. For smaller projects we build a temporary box around the saw with cardboard angled to push the chips down to the floor at the base of the saw. Yes, we do like to use our shop vacuum and even with improvised dust collection, it gets a workout. That big, ugly shop broom is a great tool to have around too.

Measure from the end of the piece to where you want the cut to be, and make a mark. With a speed square or a machinist square, make a cut line on the extrusion at the mark. Measure your line again. You can mark your cut line with your favorite marking tool. We use a sharp pencil.

This is the most important step in the process. The teeth in the blade are offset. You need to find the longest tooth on the side of the blade that faces the part you don't want cut. ( The saw is still unplugged, right? ) Line that tooth up with the side of the cut line where material is to be removed. Clamp the workpiece into place. Check it against the tooth again. Move the blade and insure that you used to align the blade was the longest tooth. Check it again. Check the measurement to the line again.

Look at the workpiece and ensure that it is square to the blade. Any material left on the stage can skew the workpiece.

The cutting process is straight forward.

With your hand OFF the trigger, bring the blade down to the extrusion and check that nothing shifted when the work was clamped.

If you are happy, plug the saw in. Now with your hand on the trigger, make your cut. The cut should be slow, letting the blade do the work. Don't force the blade down, a gentle pressure is all that is needed.

Unplug the saw. Unclamp the work and measure it.

If your are going to do another cut, clean up the chips that are on working surfaces of the saw. This is good practice between every cut as a single aluminum chip can throw off the alignment of the cut.

Ok you're done with the cutting. Clean up everything. Give the broom a good workout. Vacuum off the miter saw. Vacuum off every nook and cranny on the miter saw. Turn the saw over and vacuum it again. Clean up the floor around the saw and whatever you were using as a saw support. Remember, sharp and conductive.

Now its time to move on to drilling and tapping, but that is another instructiable.