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Elevator riveting question...

kbalch

Well Known Member
I've been motoring along pretty well and making good progress nearly every day. One task today, however, has seen me talking to myself out in the garage as I tried to figure it out.

On page 09-18 Step 5, how the heck is one meant to buck those rivets along the rear spar?!? I have the special bucking bar, but that's intended to utilize leverage (when doing the second skin) unavailable with the assembly clamped to the edge of the workbench for this step per the plans. None of my many other bucking bars fit suitably inside the rear spar. Is it a two-person job with the special bar? It'll take two hands on that bar and I'm short a third hand to run the rivet gun...

What am I missing?
 
Not sure if the pictures below are going to answer your questions, but maybe they'll help. I clamped the skeleton down firmly and that left me two hands to rivet. Used a standard tungsten bar. It's been a while, but I don't recall having a clearance issue.

The straight edge you see in the first picture is made from 1" angle with a 2" flat riveted to one side. Used double flush rivets so it would sit flat.

Used this bucking bar: http://www.cleavelandtool.com/Tungsten-Bucking-Bar/productinfo/BBT41/

14l0jt0.jpg


eln6a.jpg
 
Not sure if the pictures below are going to answer your questions, but maybe they'll help. I clamped the skeleton down firmly and that left me two hands to rivet. Used a standard tungsten bar. It's been a while, but I don't recall having a clearance issue.

The straight edge you see in the first picture is made from 1" angle with a 2" flat riveted to one side. Used double flush rivets so it would sit flat.

Used this bucking bar: http://www.cleavelandtool.com/Tungsten-Bucking-Bar/productinfo/BBT41/

Thanks! I have it clamped down firmly, but the only bucking bar I have small enough to get in there just isn't very substantial. I think that tungsten bar is the way to go. I'll order it on Monday, though the holiday next week will delay delivery. Maybe I'll get started on the tailcone while I wait...
 
Are you aware that there is a special bucking bar that is to be used in your building of the empennage? Look for it at Cleveland tools marked as a tool for the RV -10. You need it for your build also. It cost about 40.00.
I think it is used for the elevator with the trim tab, and maybe the other too. Can't remember now.
 
Yes. As I said, I have that special bucking bar, but it’s meant to aid with the second skin, not the first. I’ll see tomorrow if I can somehow make it work and, if not, will order the little tungsten bar on Monday.
 
Ok, I built both elevators myself with no help, so I am not sure exactly what you are referring. Sorry if I spoke out of turn.
 
You can reach that elevator rear spar by hanging the edge over the work table and reaching up with a bucking bar. It's possible solo. I did it with help:

http://rv-14a.blogspot.com/2014/02/empennage-elevators-rear-and-front-spar.html

Using a tungsten bucking bar makes it easy. There are several available. For the elevator rear spar, I used this one:

https://www.yardstore.com/riveting/bucking-bar/tungsten-bucking-bars/bucking-bar-tungsten-1-66-lbs

74210.jpg


At the bottom of this page, you can see a smaller one that I later used for tighter spaces. It would also work for the elevator rear spar.

http://rv-14a.blogspot.com/2015/09/fuselage-baggage-area.html

%2524_57.JPG



The special bucking bar, outlined on page 09-17, is used at a different stage, on page 09-20. It is used when you put the second skin on the elevator (since you can't reach into the C-channel of the spar with both skins on).

For most of those rivets, I used the special bucking bar with help: http://rv-14a.blogspot.com/2014/02/empennage-elevators-rear-and-front-spar.html

For the few rivets along the spar that the plans have you buck later, I figured out one way to do it solo: http://rv-14a.blogspot.com/2014/06/elevators-bucking-final-rear-spar.html
 
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You can reach that elevator rear spar by hanging the edge over the work table and reaching up with a bucking bar. It's possible solo. I did it with help:

http://rv-14a.blogspot.com/2014/02/empennage-elevators-rear-and-front-spar.html

Using a tungsten bucking bar makes it easy. There are several available. For the elevator rear spar, I used this one:

https://www.yardstore.com/riveting/bucking-bar/tungsten-bucking-bars/bucking-bar-tungsten-1-66-lbs

Thanks for the links and confirmation that the little tungsten bar is the way to go. Yardstore is a new one for me and a great find. I've just ordered the bar from them.
 
For me the section with the trim tab hinge was the hardest. Used a steel bucking bar and got acceptable results, but they are the ugliest rivets I have bucked so far. You have to buck by feel. I also made a couple of smilies in the skin. Not happy about it but it will suffice. Not going to redo the skins because of it
 
Do you really need this special bucking bar for riveting the second skin or can you use the tungsten bar for this also?

EDIT: Just ordered a piece of steel for a few bucks. It's quite narrow near the trailing edge and I'm a bit fearing for my fingers.
 
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I've been motoring along pretty well and making good progress nearly every day. One task today, however, has seen me talking to myself out in the garage as I tried to figure it out.

On page 09-18 Step 5, how the heck is one meant to buck those rivets along the rear spar?!? I have the special bucking bar, but that's intended to utilize leverage (when doing the second skin) unavailable with the assembly clamped to the edge of the workbench for this step per the plans. None of my many other bucking bars fit suitably inside the rear spar. Is it a two-person job with the special bar? It'll take two hands on that bar and I'm short a third hand to run the rivet gun...

What am I missing?

I just arrived on page 9-20, figure 1 where that special bucking bar comes in. I have the special bucking bar, but that looks like a wonderful way to screw up my elevator. The blurb above the callouts for the special bucking bar indicates that an MK-319-BS is acceptable for solid rivets anywhere this bucking bar is to be used.

My question: Has anyone else tried using Cherry's in the rear elevator spar? In the hinge portion of the left rear spar, I actually riveted it vertically, as the thought of driving down into the spar directly gave me pause.

I am leaning towards using Cherry's rather that the MK-319-BS's.

I welcome feedback from the group. THanks!
 
It is simple with the special backing bar

The special bucking bar makes quick work of the rear spar rivets. You need to let part of the bar hang off the edge of the table. You push down on the portion of the bar hanging off the table, the bar pivots on the edge of the table, then shoot the rivet. I clamped the part to the table so it didn?t move around. I don?t know how you would get in there with the tungsten bar (I have one and use it ?always?), but in this case the special bar is the way to go. - Jason
 
My tool box contains various old bodyman's hammer heads, various smoothed off chunks of bar stock, a old railroad spike, bars drilled to accept various squeezer sets, whatever works. Sometimes necessity requires creativity. Oh, I have a whole collection of usual Tungsten & steel Bucks too.
 
Sometimes necessity requires creativity.
Ralph is correct. That is the exact reason that the special bucking bar was designed.
The first prototype elevator was built using a 1/4 “ thick piece of steel plate about 3 “ wide by 18” long. It worked but not as well, and it required careful planning of the riveting sequence to avoid interference from previously installed rivets.
The custom bucking bar makes it easy because it focuses a lot of bar mass on the rivet which is important since you have to fulcrum the bar to hold it against the rivet. This excess mass makes the rivets set very easily.
 
One option is to use a bar shaped bucking bar or the rv14 Special bucking bar create a fulcrum under the bar and place the end of the bar on the shop head with the rivet gun driving the bar.

I created some diagrams on my "wiki" plans page just after the page in question. See my signature line.
 
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