Sweating a solid piece of bronze into aluminium may not be the best approach.
When it is drilled and bored it's going to grow with the heat.
Bronze is stronger than aluminium and it may stretch the bore causing the press
fit to be lost when all cools.
If I were doing that I would bore the aluminium first. Size doesn't matter much at
this point, just make it somewhere under the size of the bronze stock.
Then I would drill and rough bore the bronze .030 to .060" under the finished size
and turn the OD for .004 to .005 press on the bore in the aluminium.
High heat is not good for either bronze or aluminium.
Lay the aluminium in the sun or warm it up to not more than 250 Degrees F
while the bronze bushing spends a an hour or so in the freezer.
It will go into the bore quite easily.
Actually at size your talking about the rough bushing could be coaxed into the
bore at .005 press with a block of hard wood and a 4 pound hammer without the
sweating process. You just need to turn a 15 degree start on one end about 1/8"
long to help it enter the bore.
Theoretically you can make a brass or bronze bushing that doesn't require finishing
of the bore. If you make the bore .004" oversize and the OD to have .004" press,
Installing the the bushing brings the ID to the perfect size.
I've had the explained to me several times over the past 20 years.
I've NEVER seen it work!
Obviously it's because I did something wrong in the process... :
Rick