As I mentioned previously, the outboard rib-to-spar rivets are extremely difficult to access (Update 31-Mar-20, see below): . With the manufactured heads on the spar, the face of your rivet set is too large to seat on the universal rivet's head properly. Conversely, with the shop head on the spar, you need a very narrow bucking bar to get into the space between the outboard hinge brackets A-1006-1A and A-1006-1B (in fact, you're better off not riveting A-1006-1B to the main rib until after bucking the rib to the spar, which is contrary to plans).
Measuring the space between the outboard hinge brackets yields it to be precisely 0.5". Turns out, I have a bucking bar with just that width. Admittedly, it's poorly shaped for the task and fairly light to be bucking AD4 rivets, however I managed just fine with some planning.
Covering it with tape to prevent it from marring and removing the primer from the inside of the outboard hinge brackets, I was able to push it in to meet the shop head of the AN470AD4-4 rivets (the top-most rivet was instead easily buckable with the tungsten (wolfram) bucking bar as the taper of the brackets meant access was no longer impeded at that rivet). Here it is seemingly floating as the friction presented by the brackets hold it in place.
Then I used my 10.5" long straight 1/8" rivet set to clear the length of the top skin.
An example of how everything lines up is shown below. Obviously, I need to hold the bucking bar when actually riveting.
You can see here how awkward this approach is below. It took planning, rehearsing and great care to make sure the bucking bar wouldn't slip (even with all the friction holding it between the brackets, the violence of riveting moves the bar around and in doing so it can contact and ruin the shop heads of the set rivets previously completed) and that I wouldn't lose control of the rivet gun with the leverage inherent in using that long 10.5" set.
I would have been better off with a 13" long set since I was forced to put a slight smile into the rib flange at the top-most rivet. This was due to the 10.5" set requiring a very subtle angle to clear the skin. This is even after I removed the spring from the gun to give more clearance. However, the minimal marring was sanded out and spot primed over. Below are the manufactured heads with the slight smile on the rib flange sanded out, prior to spot priming over the area.
Here are the shop heads. The primer around the heads flaked off following expansion of the spar. This has actually been a very rare occurrence in the build overall.
Excellent. On to riveting the bottom skin to the spar, then the trailing edge wedge. Need to get the latter right this time as it didn't go well last time.
Update 31-Mar-20: Six-and-a-half years later, I decided to build another set of ailerons since I wasn't happy with how the trailing edges of the set came out. As part of having accumulated experience in construction, there is another way to buck the rivets outlined in the post above such that the manufactured heads are on the outside. See below.
Grind down a side of an offset rivet set (the tape is to prevent marring of the aileron).
Measuring the space between the outboard hinge brackets yields it to be precisely 0.5". Turns out, I have a bucking bar with just that width. Admittedly, it's poorly shaped for the task and fairly light to be bucking AD4 rivets, however I managed just fine with some planning.
Then I used my 10.5" long straight 1/8" rivet set to clear the length of the top skin.
An example of how everything lines up is shown below. Obviously, I need to hold the bucking bar when actually riveting.
You can see here how awkward this approach is below. It took planning, rehearsing and great care to make sure the bucking bar wouldn't slip (even with all the friction holding it between the brackets, the violence of riveting moves the bar around and in doing so it can contact and ruin the shop heads of the set rivets previously completed) and that I wouldn't lose control of the rivet gun with the leverage inherent in using that long 10.5" set.
I would have been better off with a 13" long set since I was forced to put a slight smile into the rib flange at the top-most rivet. This was due to the 10.5" set requiring a very subtle angle to clear the skin. This is even after I removed the spring from the gun to give more clearance. However, the minimal marring was sanded out and spot primed over. Below are the manufactured heads with the slight smile on the rib flange sanded out, prior to spot priming over the area.
Here are the shop heads. The primer around the heads flaked off following expansion of the spar. This has actually been a very rare occurrence in the build overall.
Excellent. On to riveting the bottom skin to the spar, then the trailing edge wedge. Need to get the latter right this time as it didn't go well last time.
Update 31-Mar-20: Six-and-a-half years later, I decided to build another set of ailerons since I wasn't happy with how the trailing edges of the set came out. As part of having accumulated experience in construction, there is another way to buck the rivets outlined in the post above such that the manufactured heads are on the outside. See below.
Grind down a side of an offset rivet set (the tape is to prevent marring of the aileron).
Now the manufactured heads will be on the outside.
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