MSP-42 mandrel

[stigaro]

I was building my aileron torque tubes on the weekend for my -14A. This calls for blind riveting the threaded rod ends to the torque tube using MSP-42 blind rivets. I used a pneumatic blind rivet puller for this and had 3 mandrels pull completely through the rivet. All the others broke off as expected. Since I can't see the backside of the rivet, I can't tell if the back "mushroomed" as expected.

I drilled one out and replaced it, but I wonder if I needed to? These are not trivial to drill out. Is it essential that the mandrel shank remain in the rivet after pulling? Any idea why the mandrel would have pulled out?

 

[noelf]

The mandrel can pull through the rivet if the drilled hole is too large. As an experiment, try pulling the blind rivet in free air without inserting it in a hole.