Some advice for cutting aluminium tube. I always just use a hacksaw but would like a neater solution. I have a dremmel tool but the cut off disks seem to get their pores clogged.
A saw is the traditional method, that said there are a zillion different kinds of saw blades. When you say “neater” does that mean surface finish? The carbide blade in my table saw has a 3/32" kerf and cuts aluminum cleanly and quickly. It was expensive (As I recall it was about $40 when I bought it) for a saw blade but it made cutting aluminum pretty straight forward.
Use an u-profil just a little bit smaller for fitting your tube!
For 12mm tubes i use my tool and a hacksaw.
Simple plumbing copper pipe cutter will give you a clean cut …,
I spent a few years working in a fabrication shop and the best cuts in aluminum (milling excluded) were always with a high tooth count rotary saw. I personally use a 10" 80-tooth carbide tipped blade in my miter saw. If I take time to square up the saw I can get surprisingly clean and accurate cuts.
Nobody’s mentioned lubricant? You’ll get a smother, cleaner, easier cut if you properly lubricate the blade. I’ve used 3-in-1 oil for this. This is also one case where it is acceptable to use WD-40 as a lubricant. There are special cutting fluids for aluminum that should be even better.
I use a hacksaw and leave a mm or so excess. Then I use my grinding wheel to smooth the end and then put it at a 45 and run the edge in a circle. Makes for nice rods.
Relton makes a very effective alum cutting fluid called A9. Used it for years with great results. 10" mitre is best! http://www.relton.com/cutting_fluids.html
boelube if you can find it.