Removing blind rivets with stems broken proud

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Removing blind rivets with stems broken proud

Postby SP1 » Sun Aug 18, 2019 12:48 pm

Any thoughts? The drill will wander if I try the standard way
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Re: Removing blind rivets with stems broken proud

Postby NWade » Sun Aug 18, 2019 1:39 pm

The easiest solution is to get a small punch and use a hammer with the punch to drive the rivet stem down below the rivet head. If the rivet pulled through the material the ball at the end of the rivet stem may allow the protruding bit to swivel - so be careful as you tap with the hammer. Try to strike the stem straight on (perpendicular to the rivet head).

Enjoy,

—Noel
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Re: Removing blind rivets with stems broken proud

Postby scotttro » Sun Aug 18, 2019 2:10 pm

If it's on a "delicate" surface that might deform with hammer taps, I found it's easy to cut an "X" right in the center of the stem with an ablative wheel on the Dremel. Takes the stem down a bit, and gives the drill bit a guide. Head of the rivet will protect the surface. Obviously, just a touch.
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Re: Removing blind rivets with stems broken proud

Postby SP1 » Sun Aug 18, 2019 2:33 pm

Thanks
Sort of a similar technique i tried is to use a clamp to squeeze the stem down. Having multiple methods in the quiver is a good thing to have though. Appreciate the advice.
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Re: Removing blind rivets with stems broken proud

Postby Bryan Cotton » Sun Aug 18, 2019 2:54 pm

I just used Noel's technique. The punch can be as large as the rivet to get it flush. Then use an old mandrel to punch it out completely. If you can have someone hold a bucking bar on the back makes it super easy. Bucking bar not required if there is thick structural stuff in the stack.
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Re: Removing blind rivets with stems broken proud

Postby DCASonex » Mon Aug 19, 2019 8:17 am

A light duty automatic center punch will give a quick sharp rap on the mandrel stem, much less likely to result in denting the aluminum surface than plain punch with hammer. May take a couple of knocks to dislodge the mandrel stem.

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Re: Removing blind rivets with stems broken proud

Postby Bryan Cotton » Mon Aug 19, 2019 9:00 am

The one plus of a large punch to get the stem flush is actually two plusses. First, the punch doesn't tend to slip off the mandrel. Second, the rivet head protects the aluminum as the wide face doesn't tend to slip off the rivet. Of course you can hit it hard enough to dent it with the rivet head.
Bryan Cotton
Poplar Grove, IL C77
Waiex 191 N191YX
Taildragger, Aerovee, acro ailerons
dual sticks with sport trainer controls
Prebuilt spars and machined angle kit
Year 2 flying and approaching 200 hours December 23
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Re: Removing blind rivets with stems broken proud

Postby sonex892. » Mon Aug 19, 2019 9:08 am

I knocked out countless proud mandrels in the leading edges. A pin punch worked a treat, sharp light whacks, not big heavy thuds, using electricians pliers as the hammer.

I've never tried the automatic centre punch, but it sounds like a good idea.
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Re: Removing blind rivets with stems broken proud

Postby Sonerai13 » Mon Aug 19, 2019 9:30 am

I've used a dremel with a carbide tip to grind the mandrel down till the drill will center.
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