making a simple gearbox

[carmatic]

i need to house 2 gears which will mesh with each other
these gears will have spindles on both sides... and i am planning on making 2 identical, sheet metal parts with holes to hold the gears by the bushings/bearings on their spindles

will i be specifying 'gear-spec' tolerance to the parts in comments to machinist?

also, do i space the holes apart such that the distance between their centers is the sum of the 'base radii' of the gears?

[Tech2]

The distance between centers is generally the sum of the two pitch diameters divided by two. If the general tolerance you select for the job is not sufficient you can use Comments To Machinist to tolerance this specific distance.