Hard to buck rivet...Advise needed.

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LuisR

Well Known Member

• Sep 12, 2016

• #1

Working on the tailbone final assembly. These are the J stiffners for the side skins. Bulkhead on the left. There are 4 rivets on each side skin that lay INSIDE the J channel. Every time I try to buck it with the angled part of the tungsten bar, it bends over. Tried twice so far and no dice... Suggestions?

PS, sorry for the grainy picture....Taken with a iPhone 4 with poor lighting in the cone.

 

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Tassie

Active Member

• Sep 12, 2016

• #2

Footed bucking bar

Can't see the pictures, but I know the rivets you mean.

You need one of these "footed bucking bars":

http://www.cleavelandtool.com/Footed-Bucking-Bar/productinfo/BB30

You can get the narrow foot in under the J stiffener, square with the rivet shank. You do of course need a second person outside on the rivet gun.

Regards,

Adrian

 

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AviatorJ

Well Known Member

• Sep 12, 2016

• #3

I used the tungsten bar, had to place it in right at the edge and flatten it at you drive the rivets. Still had to drill out a few... Actually saw one the other day I'm going to drill out.

 

cderk

Well Known Member

• Sep 13, 2016

• #4

Tassie said:

You need one of these "footed bucking bars":

http://www.cleavelandtool.com/Footed-Bucking-Bar/productinfo/BB30

Y

Adrian

Click to expand...

^^^ This. I used the same one and it worked well.

 

Auburntsts

Well Known Member

• Sep 13, 2016

• #5

For that rivet I used the footed bar like the others. However, in the future you may find that you'll have to modify what you have in order to get the job done unless you happen to have a large variety of bars on hand.

 

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LuisR

Well Known Member

• Sep 13, 2016

• #6

Thanks everyone. I'll get both those footed bucking bars. Thanks for the advise. I'll move on and leave those few rivets till the order arrives.

 

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paul330

Well Known Member

• Sep 13, 2016

• #7

After endless drilling out and trying again with hard-to-buck rivets, I embraced the pulled rivet. VANS philosophy seems to be to spec a bucked rivet if it remotely possible to do so. I eventually found it so much easier to use Cherry Max instead of -4 rivets and MK319BS instead of -3 (drilled out to 7/64). For the rare occasions it was necessary, I can't see how there would be any loss in strength especially when you consider the alternative of a poorly bucked rivet.

 

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LuisR

Well Known Member

• Sep 13, 2016

• #8

I definitely considered a pulled rivet in these spots. There was lots of internal frustration, sweat, and loosing patience that I thought of putting a pulled rivet. But then I decided to post here. No way I was the first to encounter such a dilemma. I must have bent over 3-4 rivets in these areas trying a different hold with the tungsten bar.

Cleveland Tools shipped my order today with a mini bucking bar and footed bucking bar. I'll give those a shot. If that fails...then I'll do a blind rivet no question.

I'll post an update once I get the shipment.


Are the photos showing up on the first post?

 

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leok

Well Known Member

• Sep 14, 2016

• #9

There are some really difficult rivets in the forward fuselage as well. I picked up some 1" square bar and other useful looking bits (hot rolled mild steel) and used a HF $16 grinder to form some custom bucking bars. Shine 'em up and knock off the edges the on the belt sander and they do a nice job.

Most steel suppliers have a scrap bin for cut offs they sell by the pound.

 

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LuisR

Well Known Member

• Sep 16, 2016

• #10

Update:

Cleveland Tools SHIPS SUPER FAST!!!! Bucking bars arrived and worked perfectly for the hard to reach rivets in the stiffness.

Thanks everyone.

 

rdamazio

Well Known Member

• Sep 17, 2016

• #11

I used one of these for those rivets:
http://www.aircraft-tool.com/shop/detail.aspx?PRODUCT_ID=AT750P
Not easy to keep it straight without letting the thinner tip touch the J channel, but I managed.