I have just started on a Kossel Mini (variant) build from scratch,

I have just started on a Kossel Mini (variant) build from scratch, and I’ve run across a very basic problem:
What is the best way to accurately cut aluminum extrusion at home? I bought several 1 meter pieces, not knowing what I would end up using them for, and now I need to cut them to size.
I live in an apartment, so I don’t have bench power tools like a cutoff saw. I tried with my Dremel and a cutoff wheel, but it’s hard to get a clean cut through 25mm extrusion (thus, the variant). A hacksaw seems equally difficult to cut straight. I’ve also looked, and not found any hackerspaces near me.
Any suggestions from those who have done this before?

I have used a skill saw, the accuracy is not the greatest but it works.

Great question Carlton. I too live in an apartment and face the same problem. I’m considering asking if I can use the “wood shop” at a local Private K-12 school if I can use their shop but otherwise at home… the thought of a hacksaw… well… maybe its better than going to the gym…

@Wayne_Friedt Thanks. I’ll keep that in mind if I don’t find a truly accurate method.
I suppose the ends of the extrusion on a Kossel don’t have to be perfect, as long as the distances on each of the sides is equal. Or, am I wrong there?

I built this printer using the skill saw method on some 20x20. I would say you are correct.


I have a Lathe that has a spindle through hole big enough to take the extrusions. You can bed borrow or steal someone locally that is equipped (any local Makersheds in your town?)…the alternative is designing the printer so that extrusion length doesn’t dictate precision. My 3DR can have extra extrusion length just stand up above the rest of the printer…each corner slides down over the extrusion…and all that matters is that each leg is equal in length…so three pieces can be 310, 320, and 315 in length, but the distance between top and bottom printed parts can be measured to 300mm.

Miter saw with aluminium cutting blade. Easy enough to use in a kitchen, just have to vaccuum the debris afterwards. I got a craftsman one at ace hardware for $90. $18 for alum blade on amazon.

Miter saw is a good idea. If you want the lengths to match, I would also recommend lining them up together, binding them with masking tape, and cutting all three at once.

If you try to use a dremel, don’t use a cut-off wheel. Those are abrasive cutters, and they’re good for steel, but for aluminum you want an actual saw blade.

My method:
$15.00 and use a hacksaw with a fine blade.

Measure out, leave a little extra and use a bastard (hand file) to finish. When I laid out all pieces that are to be the same length, I could lay a straight edge across both ends and was accurate enough for me… And the machine :-).

I think that may be the winner.

@Brandon_Satterfield about how long does it take to go through one?

I just ordered a hacksaw (better than the one I have), 32tpi blades, and an aluminum miter box. Thanks for the advice!

The miter box is the right answer (or a miter saw which includes the saw in the configuration). You can “fake it” since you’re only making perpendicular cuts with some clamps and a hacksaw. If you are going to do a lot of fabrication with extrusion it can be helpful to make some holding jigs that are pre-set to hold it.

I think I saw a saw fixture in http://thingiverse.com precisely for this purpose.

@Carlton_Dodd glad I could be of assistance!

@John_Baronian I was cutting through 20x40, and having a cold one… Time wise not sure but cut 4 ends in one beer…:-). I would estimate with a new blade 4-5 min per.

Another thing I am remembering I put a C-clamp on the extruded Al to the miter box, this great increased accuracy and greatly reduced frustration.

@Carlton_Dodd very interesting post since this question has been on my mind for a while too. I finally went the same direction and got a miter box, though I only found plastic ones.

This also looks like a nice tool though the shipping might be a deal-breaker for me;

It sure is a constant struggle to make stuff without the space/place to use good power tools.

Very nice find, thanks! If I needed more than a dozen cuts, this might be worth the cost.
Looking at the design, though, maybe we could make something similar using inexpensive 8mm drill rod for the guides and a sturdy printed base. I have some extra rods laying around; I might try this.

Just received the aluminum miter box and hacksaw I ordered. Made three cuts, lengths are within 0.5mm of each other and very close to 90 degrees by my eye.
Thanks for everybody’s help!

@Carlton_Dodd I found some other sources of inspiration for a DIY mitre box that’s interesting in their own ways;