Brockster
Well Known Member
I have begun the assembly of the center section and have two questions.
1, When you attach the F-904C-L&R center sections to the F-904A fwd bulkhead and the F-904D-L&R center sections to the F-904B aft bulkhead, the instructions say to install one NAS1307 bolt in the top and bottom to align everything before drilling rivet holes to size. Using a little lubricant and slight pressure I was able to do this in the forward bulkhead but not the aft. On the aft bulkhead I can fit the shank of the bolt in the 5/8" thick bar if I feed the bolt from that side or if I feed it from the web side the shank will fit in the hole in the web but stops at the 5/8" bar. (shank of bolt being the smooth portion, not the threaded part, tried all eight holes and several bolts) It almost seems like when the aft bulkhead was riveted together that it might have been misaligned by a couple thousandths. Anyone have any similiar experiance here? My thought might be to use a little emery cloth on the hole in the web portion of the bulkhead since it can be pryed away slighty from the bar to polish the hole a little. I believe this step is important because I could see how riveting the sides on to the bulkhead you could ever so slightly have the wing bolt holes misaligned making it even more difficult to install them later. A close tolerance bolt should only take a 12 to 14 ounce hammer to "tap lightly" it in. Anything more and the fit is not right in my opinion.
2. Vans says the NAS1304-50 and the NAS1307-50 bolts are close tolerance bolts. Mine seem to be standard NAS bolts. I thought a close tolerance bolt should have a raised or recessed triangle on it. Mine don't. Also the shank should be polished with no cadmium plating and a plastic sleeve on it to protect it. Mine just have some red rubber tips covering the threads. When installing these, the cadmium plating does peel slightly and the build up could definitely cause the bolt to bind once thy are installed with the wing spars. This also could be my problem in question one.
Any thoughts would be greatly appreciated.
1, When you attach the F-904C-L&R center sections to the F-904A fwd bulkhead and the F-904D-L&R center sections to the F-904B aft bulkhead, the instructions say to install one NAS1307 bolt in the top and bottom to align everything before drilling rivet holes to size. Using a little lubricant and slight pressure I was able to do this in the forward bulkhead but not the aft. On the aft bulkhead I can fit the shank of the bolt in the 5/8" thick bar if I feed the bolt from that side or if I feed it from the web side the shank will fit in the hole in the web but stops at the 5/8" bar. (shank of bolt being the smooth portion, not the threaded part, tried all eight holes and several bolts) It almost seems like when the aft bulkhead was riveted together that it might have been misaligned by a couple thousandths. Anyone have any similiar experiance here? My thought might be to use a little emery cloth on the hole in the web portion of the bulkhead since it can be pryed away slighty from the bar to polish the hole a little. I believe this step is important because I could see how riveting the sides on to the bulkhead you could ever so slightly have the wing bolt holes misaligned making it even more difficult to install them later. A close tolerance bolt should only take a 12 to 14 ounce hammer to "tap lightly" it in. Anything more and the fit is not right in my opinion.
2. Vans says the NAS1304-50 and the NAS1307-50 bolts are close tolerance bolts. Mine seem to be standard NAS bolts. I thought a close tolerance bolt should have a raised or recessed triangle on it. Mine don't. Also the shank should be polished with no cadmium plating and a plastic sleeve on it to protect it. Mine just have some red rubber tips covering the threads. When installing these, the cadmium plating does peel slightly and the build up could definitely cause the bolt to bind once thy are installed with the wing spars. This also could be my problem in question one.
Any thoughts would be greatly appreciated.