Still, if your heart is set on a mill, who are we to stand in the way? But even as it is, this tool gets the job done, and doesn’t break the bank like a mill purchase might. Adding some quick-throw toggle clamps would be a nice touch, as would extending the MDF bed and fence a bit for longer cuts. We love the simplicity and utility of this jig, but can see a couple of areas for improvement. Check out the video below for a peek at the build details.

A fence and clamping system holds the extrusion firmly, and once trammed in, the jig quickly and easily squares extrusions that have been rough cut with a miter saw, angle grinder, or even a hacksaw. ’s mill-less solution uses a cheap Harbor Freight router as a spindle for a carbide endmill, riding on a laser-cut acrylic baseplate fitted with wheels that ride in the V-groove of - you guessed it - aluminum extrusions. But without square cuts, any frames built from them can be seriously out of whack, leading to misery and frustration down the road. There’s no doubting the utility of aluminum extrusion in both prototyping and production builds, nor that the versatile structural members often add a bit of class to projects. Sadly, it’s much more cost-effective to build this DIY squaring jig, and search for your tool justification elsewhere. If you’re looking for the perfect excuse to buy that big, beautiful Bridgeport mill, we’ve got some bad news: it’s not going to be making perfectly square end cuts on aluminum extrusion.

3d printer t slot extrusion