Cherry Max rivet not fully seated

[bertschb]

I used Cherry Max rivets for the first time recently and one of them didn't seat flush to the material on the "factory" side. Not sure if I should drill this one out. The gap under the head is .006". Thoughts??

Update: Just read this in Section5: "Base of manufactured head should be tight against surface of material being riveted." Time to remove my first CherryMax...

 

[fixnflyguy]

Welcome to the miserable world of cherrymax removal! It would likely never come loose, but what is it actually holding together? Seems there are solids right next to it. To remove a cherrymax, you must carefully drill down the stem with a bit same diameter as a stem to be able to pop out the incinel lock ring. After that happens, you can pin punch the anvil back out and drill the head off..carefully. You don't want it to spin. When reinstalling , make sure it's fully seated before pulling.

 

[bertschb]

...It would likely never come loose, but what is it actually holding together?

It's part of the RV-14 lower longeron assembly (page 29-07). I pretty much knew I needed to drill this one out but was hoping somebody would say something otherwise because I read somewhere that removing Cherry Max rivets was not fun. I didn't want to make things worse. I also know there is a reason there are six Cherry Max rivets in this area along with six AD4's. I've drilled out plenty of solid rivets but I've actually never needed to remove any kind of pulled rivet yet.

 

[agent4573]

If you have access to the backside, it might be easier to sand off the anvil and retainer, knock the stem out the front side, then drill the head off and punch it out. If you sand 80% of the backside off with a Dremel, all the retaining features will be gone and it should act similar to a standard pulled rivet for the rest of the removal.

 

[Brantel]

If you have access to the backside, it might be easier to sand off the anvil and retainer, knock the stem out the front side, then drill the head off and punch it out. If you sand 80% of the backside off with a Dremel, all the retaining features will be gone and it should act similar to a standard pulled rivet for the rest of the removal.

Remember that CherryMax rivets also have a locking collar on their manufactured head side.

 

[Dr_Dave_MT]

I would take some scrap parts, install several cherry rivets and practice removal of them all on the scrap. Once I felt pretty comfortable, I'd take a shot of bourbon and remove the real ones....

 

[Ron B.]

I would take some scrap parts, install several cherry rivets and practice removal of them all on the scrap. Once I felt pretty comfortable, I'd take a shot of bourbon and remove the real ones....

I used Cherry Max rivets for the first time recently and one of them didn't seat flush to the material on the "factory" side. Not sure if I should drill this one out. The gap under the head is .006". Thoughts??

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I would think this is a high stressed area ( engine load) and it should be set correctly. You either didn’t have the rivet fully into the hole when pulled or something was stopping it from sitting tight.

 

[bertschb]

I would think this is a high stressed area ( engine load) and it should be set correctly. You either didn’t have the rivet fully into the hole when pulled or something was stopping it from sitting tight.

It is a high stressed area (hence the call for Cherry Max rivets) and I do plan on removing the rivet.

I'm wondering if I need to lubricate them? I read about that in section 5. It says to lubricate them if the mandrel breaks off prematurely. Is this what happened here? Pretty darned sure it was fully seated in the hole prior to pulling the rivet. I've pulled at least a couple hundred rivets (not all Cherry Max) and this was the first that did this.

 

[bertschb]

Update:
I just removed and replaced the rivet. The hole was in perfect shape when I removed it. I then lubed the replacement rivet and pulled it. Looks perfect now! Thanks for your feedback guys.