Martin Eastburn wrote in news:PUzGv.194874$ne6.53439
@fx09.iad:

Heating the aluminum tube might expand it more than the thickness of the
metal. If so a hot tube might swallow a dowel and cool skin tight.

No, it won't. Aluminum expands about 12 parts per million per degree Fahrenheit. It would have
to be heated to over 800 degrees F to increase the ID by just 1% -- and that's not nearly
enough to make the ID as large as the room-temperature OD.

We won't even talk about what that would do to the wooden dowel...