Michael Burbidge
Well Known Member
How did you get a bucking bar on the 4 top-skin to rear spar rivets adjacent to the W-907-C doubler? The edge of the doubler overlaps the rivets shank about in the middle of the shank.
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Skin to rear spar rivets near W-907-C doubler...
- Thread starter Michael Burbidge
- Start date
Skin to Rear Spar Rivets
Just did those last week. Yes, they are tough to reach with the doubler plate and rivets in the way. Cleaveland sells a "Footed Bucking Bar" part number BB30, that has a wedge end that will slip in between the doubler plate and rear spar flange. Those 4 rivets aren't the prettiest in my wing, but they will do.
Just did those last week. Yes, they are tough to reach with the doubler plate and rivets in the way. Cleaveland sells a "Footed Bucking Bar" part number BB30, that has a wedge end that will slip in between the doubler plate and rear spar flange. Those 4 rivets aren't the prettiest in my wing, but they will do.
This is one of those points where it's helpful to remind yourself that ANYthing can serve as a bucking bar. All you need is a piece of metal with some mass behind it, that can serve as an anvil to the rivet guns hammer. I've used a piece of iron rebar from concrete work, I've used the edge of a back-riveting plate, once I even used the handle of a crescent wrench. Tight quarters make for interesting riveting, but the goal is always the same - smash the rivet. I'm good at finding new and innovative ways to smash stuff. 
I don't know if you have one yet, but the small tungsten bucking bars are just about the best thing since sliced bread and canned beer. There is enough mass to buck any size rivet, and they are small enough to fit in (almost) any space.
I don't know if you have one yet, but the small tungsten bucking bars are just about the best thing since sliced bread and canned beer. There is enough mass to buck any size rivet, and they are small enough to fit in (almost) any space.
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I'll second the tungsten bucking bar. I originally thought, who in their right mind would pay $100 for a lump of metal when nearly any piece of steel will do? Well the wife loves the smaller bar, it's easier to hold for her and anything that keeps her happy and helping in the shop is money well spent! Seriously, it is worth the money. We never reach for any other bucking bar any more and it fits in the smallest of spaces.
I got mine off Ebay from http://www.tungsten.com/bucking.html, specifically the BB-7 model. 1x4 with one angled face that's about 5 degrees. That little angle has really come in handy.
I got mine off Ebay from http://www.tungsten.com/bucking.html, specifically the BB-7 model. 1x4 with one angled face that's about 5 degrees. That little angle has really come in handy.
mculver
Well Known Member
Old thread, but relevant to a question that I have. Am riveting the W-907-C in place on the 9's rear wing spar. Per the question in this thread about how hard it is (later on) to buck skin rivets around the top of the W-907-C, wouldn't this be an easier job if the round-head rivets were instead flat-head rivets countersunk into the doubler?
Of course my question has nothing whatsoever to do with the fact that I "thought ahead" and accidentally countersunk these holes already. But upon reflection, I just might have done good.
Any thoughts from others? I am essentially saying that the doubler would be 100% countersunk rivets instead of a row of round-heads at the top. (I have to drill this out no matter what, because I also forgot to dimple the flange.)
Of course my question has nothing whatsoever to do with the fact that I "thought ahead" and accidentally countersunk these holes already.
But upon reflection, I just might have done good.Any thoughts from others? I am essentially saying that the doubler would be 100% countersunk rivets instead of a row of round-heads at the top. (I have to drill this out no matter what, because I also forgot to dimple the flange.)
Mike, I accidentally did the same thing. When the countersunk hole is not knife-edged (countersink depth extending all the way through the part), a countersunk fastener is actually stronger in shear than an equivalent-sized universal-head (AN470) fastener. This is because the joint actually sees a little benefit from the average fastener area being increased.
In tension, the countersunk fastener would not fare as well as the universal-head fastener. But this is a shear application, and tension is not normally the critical loading condition for rivets on our RVs.
The thickness of the doubler makes this absolutely nothing to worry about. In fact, you're exactly right about your "mistake gone good" comment. You did the structure a favor by countersinking.
Not sure I'd continue to deviate from plans for 100% of the rivets there, however, but only for the simple reason that I found it no problem to buck the skin rivets with my small tungsten bucking bar. If you don't have one of those yet, you'll be amazed when you try one.
In tension, the countersunk fastener would not fare as well as the universal-head fastener. But this is a shear application, and tension is not normally the critical loading condition for rivets on our RVs.
The thickness of the doubler makes this absolutely nothing to worry about. In fact, you're exactly right about your "mistake gone good" comment. You did the structure a favor by countersinking.
Not sure I'd continue to deviate from plans for 100% of the rivets there, however, but only for the simple reason that I found it no problem to buck the skin rivets with my small tungsten bucking bar. If you don't have one of those yet, you'll be amazed when you try one.
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