Garage method of enlarging hole in brake rotor?

so the rotor i want to use has a smaller center diameter than the axle has. Aside from the obvious lathe or mill, neither i have, is there a good method to do this, or should I what and try to pay a machinist sometime in like Winter when I'll have the funding.

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First Rally: 2010 First RallyX: 2004 (a bunch)
Driver (0), Co-Driver (7)
Organizer (3), Volunteer (3)
Cars Built (2.5), Engines Blown (2) Cages Built (0) # of rotations (3.5)
Last Updated, Apr 9, 2023

How much bigger does it need to go? Is the rotor a tighter fit onto the studs, or is there a lot of slop?

Need to drill the pattern too.

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First Rally: 2010 First RallyX: 2004 (a bunch)
Driver (0), Co-Driver (7)
Organizer (3), Volunteer (3)
Cars Built (2.5), Engines Blown (2) Cages Built (0) # of rotations (3.5)
Last Updated, Apr 9, 2023