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Drilling out Cherrymax

Rallylancer122

Well Known Member
I have to drill out a bunch of flush head cherrymax rivets. Yeah....ugh. I've searched it a bit and not much advice out there. I know I need to drill out the lock and then I can just punch out the stem, but that's harder than it sounds. Any tips or tricks.
 
You can remove a flush cherry rivet in 3 steps.
Usa a # 40 cobalt bit, drill in the very center. This will remove the locking collar by heat and spinning. You cannot drill the locking collar as it is high tensile steel.
With a small diameter sharp punch hit the center stem of the rivet to drive it from the rivet body.
Drill the aluminum body of the river with a # 30 drill bit for 8th inch rivet until the flush head comes off.
Then punch out the rest of the rivet.
 
depends on access, but I've had success grinding the collar off with a dremel. It isn't very deep, if you grind off approx 1/3 to 1/2 of the head height it's gone and you can then punch out the stem.
 
depends on access, but I've had success grinding the collar off with a dremel. It isn't very deep, if you grind off approx 1/3 to 1/2 of the head height it's gone and you can then punch out the stem.

My IA friend had me help replace an aileron on a C152 with the above method. (He’s trying to make an airplane mechanic of me. Good luck!) We replaced a hinge attached with Cherrymax rivets. He has a selection of .032” (?) steel shims with holes drilled in them. The hole goes over the rivet. When the Dremel slips off the rivet, less cussing happens. Cussing is directly proportional to extra work created. Shim protects the surrounding material. The different shim shapes are for getting the shim into different locations.


Edit: the Dremel slipped several times that morning. No cussing occurred. :)

My apologies for dome head rivet technique. I’ll ask if he has a flush / countersunk technique.
 
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oops- I didn't notice in the original post we were talking about flush heads- Drilling is the way to go then.
 
Just to bookend this one....

Cherry had a video on their website that recommended using a center drill to drill out the lock. This worked for one rivet but I couldn't make it work again.

I ended up using a cone shaped grinding stone in a Dremel tool. ( This stone likely came with your Dremel kit and has been collecting dust for 10 years while you wonder what it's good for. Well, its good for this.) This is delicate surgery for sure, but with a little patience you can dish out the rivet head a sixteenth or so which allowed me to punch out the stem.

If you have to do a lot of these I would find the pilot at your airport that's a dentist ( there's a dentist at every airport) as he likely does this every day.
 
Feeling your pain...I just put 38 cherry max in I need to drill out forgetting the doubler that was supposed to go on under them. After 6 it's getting a lot easier. Pretty much using that technique above as you can't punch out the center until you drill it first. The panic is starting to wear off.

Doing stupid stuff is the most frustrating thing about building.
 
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