[gpraceman]

I'm looking to mill a 1" x 1/4" slot through the middle of some 80/20 1010 extrusion so I can run some wires from the front T-slot to the back one. Would it be best to drill a 1/4" hole on one or both of the ends of the slot and then mill out the middle or just mill it all out? I was thinking that drilling first would help with chip evacuation.

[mcarvey]

I don't think chip evacuation will be too much of an issue- you can always hit it with a vacuum if it looks like it will be a problem. I'd be a bit more concerned about the sharp aluminum edge cutting the wires. I would definitely be fairly generous with the post filing to make sure there are no really sharp edges.

-Matt

[GeorgeRace]

I also think the sharp edges should be avoided for wire passage.
There is a lot of "Build A Grommet" nylon strip out there that I would recommend for a protection/finish look.
George

[gpraceman]

I'll make sure to watch out for sharp edges. Once the wires are run, both sides will have T-slot covers put over them. The wires will not move around in any way.