Need to increase the ID of square aluminum tubing...

I have the following:

A) 2" OD square tubing with 0.25" wall thickness. This is 8' long.
B) 2.5" OD square tubing with 0.25" wall thickness (so ID is nominally 2"). This is just 7.5" long.

Both A and B are 6061 aluminum.

I want A to fit inside of B, but it's ever-so-slightly too big (less than 1/64" and probably closer to 1/128"). Yes, I can use a sanding wheel on an angle grinder, and shrink the OD of A to fit inside B, but that's not suitable for my particular application. Instead I want to increase the ID of B so that A will just fit inside.

The only thing that I can think of is a hand file, but that's super-de-duperly slow going, and definitely no fun. I'm just wondering if anybody has a better idea...

I don’t think it would take as long as you seem to think. Maybe you could attach a file to a saws all or wrap a saws all blade with sand paper to make a power sander.

I don’t think it would take as long as you seem to think. Maybe you could attach a file to a saws all or wrap a saws all blade with sand paper to make a power sander.

That’s a thought—a reciprocating power sander/file…

Perhaps something like this?

https://www.homedepot.com/p/WEN-Variable-Speed-2-Amp-Detailing-File-Sander-with-1-2-in-x-18-in-Belt-6307/302355174

Perhaps something like this?

https://www.homedepot.com/p/WEN-Variable-Speed-2-Amp-Detailing-File-Sander-with-1-2-in-x-18-in-Belt-6307/302355174

That’s the ticket!