I have some I bought for my trailer, I think they are 5/32, they might be too big for what you are looking for.
http://www.vintagetrailersupply.com/category-s/206.htm

here is a link to their buck riveting basics manual

http://www.vintagetrailersupply.com/v/vspfiles/assets/images/BuckRivetingBasicsInitialRelease.pdf

Last edited by 69Cuda; 05/30/2017 1:52 AM. Reason: added link

Mike
1955 Chevy 6400 ex-flatbed (no bed now!) sold September 2023
In the Stovebolt Gallery
1958 Chevy 6400 flatbed W/dump
In the Stovebolt Gallery
1959 Chevy Suburban Owned for almost 20 years, Daily Driver -- sold May 2016
In the Stovebolt Gallery

Sufficient unto the day is the evil thereof