Hi Fred
Vans in an RVator article gives authority to use MK 319 BS in place of AN426AD3-3 and 4 solid rivets. In a seperate email Vans said I could use them on the trim tab in place of the CS4-4's. I couldn't find too much about these rivets so after some experiments I found the following:
1. If you know you are going to use these in advance drill/match drill to 7/64" and dimple with a 3/32" die. The die enlarges the 7/64" hole and permits the MK 319 BS to fit.
2. If you DECIDE AFTER you've drilled/match drilled to 3/32" and dimpled with a 3/32" die then drill out with (in order of availability) a 3mm, 1/8" or #30 drill to permit the rivet to fit.
Personally I have no qualms about using these, particularly those out of sight (under the trim tab, flap etc) as it saves a lot of hassle. No doubt the purists will be spitting blood at the very thought!
Hope this helps?
Bob Ellis
RV-8 Fuselage in progress
www.rv-8.co.uk