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Mandrel for pop riveter dimple dies

skelrad

Well Known Member
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I have the close quarters dimple dies from Cleaveland. They came with a few copper mandrels, but I’ve found that on anything other than super thin sheet, those just aren’t up to the task (they stretch and break). I’ve always heard that you can just use a finish nail as a mandrel instead, but I can’t find a nail with a head size that works. For the right nail diameter that fits through the die hole, the head is just barely larger and pulls through the die when squeezed. What’s the trick?
 
Don't know what nail you are currently using but I use the 6D 2" finish nails and they work fine. The brand is Grip Rite (smooth shank). Don't know if this makes a difference?
Hope this helps.

Arnie
 
Don't know what nail you are currently using but I use the 6D 2" finish nails and they work fine. The brand is Grip Rite (smooth shank). Don't know if this makes a difference?
Hope this helps.

Arnie

I bought a box of 6D nails thinking that was correct, but the heads are just too small. If that’s the right size, I’ll try another brand to see if the head is bigger. Thanks!
 
Agree, the copper pins shipped with the dimple die kit are useless for our needs.

I also moved away from finishing nails during my build and now exclusively use a standard nail with a flat top. There is some distortion in the metal around the head area where the grip groves are stamped into the nail .... so just a little dressing on a Scotch-Brite wheel just under the head of the nail and the nail will slide all the way into the dimple dies and sit flat on the die. The standard nail is reusable many times unless you put the Kung Fu grip on your rivet puller... give it a go, bet you will not go back to a finish nail.
 
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Agree, the copper pins shipped with the dimple die kit are useless for our needs.

I also moved away from finishing nails during my build and now exclusively use a standard nail with a flat top. .... The standard nail is reusable many times unless you put the Kung Fu grip on your rivet puller....

John,

I've not had any such luck, the heads snap off.... Are you using any particular brand?

Thanks,
Mike
 
Sorry Mike ... can't tell you the brand, as the nails were purchased many years ago when I was building.

Most of the RV-12 metal I was dimpling was .020 ... if you are dimpling much thicker metal, perhaps that is why you are having a different experience than I did.

Is it possible you are over squeezing the hand rivet puller? The dimple forms just as the hand puller really tightens up .... squeezing much harder beyond that point does not do much more dimple forming. Try making dimples in some some scrap by taking the hand puller to the point it gets tight, give it just a little more tension and then check the results ... you may find it is good enough.

Also, it has been my experience that hand formed dimples using close quarters dies with hand rivet pullers are typically not quite as pristine as dimples formed with a pneumatic squeezer.
 
My close quarter's dimple dies came with nails in addition to the copper mandrels. I'm not sure what they are but they have a large flat head. You could probably give Cleaveland a call to find out what they use.

When I first started using the dies the nail heads would often break off but I've since learned that it doesn't take much force on the squeezer to form the dimple and it will fully form long before the nail will break. It just takes a little practice.
 
I too moved to nails, and found a brand whose head was just barely big enough. Actually, it's still too small because with many uses the holes in the die are all messed up.

The other problem is the grooves on the nail. Maybe my rivet tool's teeth are super aggressive, but after a handful of dimples, the only way to get the dies to slip off the nail is to grind the nail down with a grinding wheel.

In summary, I too am hoping someone else replies with just the right mandrel, because I haven't found it yet, and I've tried several kinds of nails.

Also, one person above mentioned using a Scoth-brite wheel to grind down the grooves on a nail. I also read elsewhere that you don't want to use the same Scotch-brite wheel on both steel and aluminum as the steel gets into the material and will transfer to the aluminum later. Don't take my word for it, though, as I'm no expert.
 
Back to copper studs...

~20+ odd years ago, I started with the copper mandrels (aka. draw pins) that came from Bob Avery. I didn't like that they would stretch after a few holes and had to use a new copper mandrel.

As the original close quarter dimple dies only came with 4 or 5 of these things, it was necessary to find a longer lasting replacement. Enter the Home Depot finish nail; the finish nails lasted forever, imparted a (relatively) clean dimple, but were a bit too hard for my blind rivet puller's jaws.

After rebuilding my pull rivet tool, I went back to the draw pins -- but I had found a source (auto body supply shop in town) -- 500 for <$20. Dimples are acceptable, and the don't mess up the jaws in my hand puller or pneumatic puller.

Of course YMMV.
 
Built more than a few airplanes using only pop-rivet dimpler and vice-grip dimpler. If you have a pneumatic rivet puller, practice on scrap. Turn the air pressure almost off. Keep increasing pressure until you have a good dimple. I can typically do an entire wing skin with maybe 3 nails. You will have to stop every 20 - 30 holes and dress down the nail where the puller grabs it.
 
Pop Rivet Mandrels

Disclaimer: This may not be for you - as you can lose a mandrel each time you make a dimple IF you use a pneumatic/cordless puller. If you don't pull to "break" - you're good to go until you do.

What the pic shows:

.025" 6061-T6 with 1/8" x 120* pop rivets & -3 x 100* solid rivets. I "harvest" the mandrels from Pop 5/32 SS rivets w/SS mandrels (.094" dia.).

As noted on the photo, I pull them to "break" to insure maximum and repeatable performance every time.

Yes, it's a bit more effort, but if you only need them once in a while, it does give the best results.

Note: It's possible the holes in the dies may be slightly undersized - if yes, then just drill them out.

HFS
 

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Nails

I take the dies to the local aviation supply (hardware). They have a bulk bin. I just dig and test to make sure they fit. Handful lasts forever.
 
I measured the head diameter of the (smooth shank) Grip Rite nail I mentioned in post #2 above and it is .134. Lowes or the Depot has that brand.

They work great.

Arnie
 
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