Subframe rivets

[John Duden]

What rivet pattern is correct for the subframe rivets? I see the venders sell a waffle air hammer bit is this correct?

 

[Brentwood Bob]

as I reread your question I see that the subframe would use a waffle tool.
Not positive this is 100% correct.

 

[Randy in ca]

Here's a picture I took a few years ago when disassembling the remains of subframe from a roadster cowl post.


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[rotorwrench]

Ford used large hydro pneumatic squeezers to set the rivets. The waffle pattern on the anvil was likely to prevent it from slipping off during the squeezing operation. Using an air hammer is another way to try to get an authentic looking driven rivet. I prefer to drive the head with the rivet gun and buck the tail with a bar. From many years working with aircraft rivets, I've found that the bucking bar likes to bounce a bit while the set in the gun is hammering away. When using a waffle head set in the gun, it can bounce as well and make a funky pattern in the buck tail. A bucking bar with the waffle pattern would be better no one manufactures such a thing. This link shows how one person delt with this problem.
http://www.fordgarage.com/pages/bodyrivettools.htm