S

SteveK

I'm New Here
I am trying to use CherryMax CR3213-4, -2 & -4 rivets to secure the leading edge wing assembly to the spar of my RV-8 wing. Most of the rivets are not pulling all the way and are breaking well before fully seating.

Is this a problem with my basic rivet puller? I have ground down the tip of my puller to get it as straight as I can, but may have a very slight angle when pulling.

Any ideas on removing cherry max rivets?

SteveK
 
???

Steve, I'm curious why you chose to go with cherrymax for this part of the wing construction?
 
Removing Cherrymax

Steve,
One method of removing Cherrymax is to very carefully (underline five times) grind the center of the factory head with a Dremel tool equipped with a miniature grinder or diamond tip.

Recommend you mask off the area around each rivet using duct tape in case you slip with the grinder.

Once the center of the rivet head is almost ground off it should release the rivet enough for removal...but you may have some drilling to do in the center.

These are a pain to remove...so allow plenty of time for each rivet.

I'd go with standard rivets once you get these out.

Good luck,
Mike
 
It was the recommendation from Vans. I asked about the LP4 and he said I needed something stronger and structural like the Cherrymax.
Steve
 
Cherry info

Steve,
Cherrys can be a bit tough, but very doable.
When installing it is important that when you pull the stem, that the rivet be allowed to seat properly. If the head is tipped at all, the stem can break short. Let the rivet pull the tool inline the way it wants. I begin removal by just touching the stem with a 2 inch sanding disk to smooth off the surface, then drill the lock with a number 40. Sharp tools are a must. It is possible to get a "trophy", the lock ring as a ring. Then knock out the stem. Grinding as previosly mentioned works, but as a last resort, for me. Whatever it takes to not remove sheet material! Dimped holes will open up some every time a blind rivet is installed, so mind the hole tolerance. Also note that the dash number is the maximum grip range, they come lightly lubed and can dry out, and stems .010 high or.020 low are in tolerance. I know this from Cherry literature.
Good Luck!
 
Might Help

SteveK said:
I am trying to use CherryMax CR3213-4, -2 & -4 rivets to secure the leading edge wing assembly to the spar of my RV-8 wing. Most of the rivets are not pulling all the way and are breaking well before fully seating.

Is this a problem with my basic rivet puller? I have ground down the tip of my puller to get it as straight as I can, but may have a very slight angle when pulling.

Any ideas on removing cherry max rivets?

SteveK
Click to expand...

Others have given good advice such as drill bit size and tecnique.

My suggestion is a cobalt drill bit that is split point tip. Only drill enough to get the lock ring out.

I think that if they are not pulling right you have more problems. My suspicion is that you are using too long of a grip length. It should correlate to the full countersunk head on the outside to the pointed part of the dimple where the shop head will be forming.

The grip length of cherry-max for Flush head types includes the head, the universal head ones disclude the head. Here is a link to our tech page.

http://www.gen-aircraft-hardware.com/images/pdf/cherry.pdf

I hope this helps. Best wishes:)
 
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