To install a hot rivet you need the hole oversize for the rivet, otherwise you can't get it together in a hurry, in addition to the rivet expanding with the heat.
The hot rivet should swell up and fill the hole when you set it/form the head on the other end.

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-