Edgeflyer Posted September 17 Share Posted September 17 I'm refurbishing this old model. Can anyone tell me what the thread is on these old wing bolts? Seems coarser than M5. Also they are clearly off "vertical" due to slight warping of the blind nuts plate. I may need to insert a new plate underneath containing correctly set blind nuts in which case I may stick with M5 Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted September 17 Share Posted September 17 (edited) If your going to have to reset the nuts just go for M5 . The course threaded bokt seem to be uused on loads of artf stuff probably a english thread for the American market. Edited September 17 by Engine Doctor 1 Quote Link to comment Share on other sites More sharing options...
Jim Hearnden 1 Posted September 17 Share Posted September 17 The old thread used to be 1/4UNC Best option is to use an M6 tap & re-tap to M6 and use M6 nylon bolts. Probably easier than removing the captive nuts and replacing. Looking at my thread tables M6 tapping size is 5mm 1/4 x 20TPI UNC is 5.525mm so not strictly kosher but should be OK. Quote Link to comment Share on other sites More sharing options...
Bruce Collinson Posted September 17 Share Posted September 17 Or buy some from Modelfixings. Quote Link to comment Share on other sites More sharing options...
kc Posted September 17 Share Posted September 17 SLEC used to supply 2BA wing bolts and so it could well be 2 BA. The wing bolts are oten not vertical but slanted to allow the bolt head to be 'parallel' to the wing surface, the wing bolt plate is then also slanted to be at 90 degrees to the bolt. Quote Link to comment Share on other sites More sharing options...
Edgeflyer Posted September 17 Author Share Posted September 17 Ok thanks all. In the event I decided to see how feasible it would be to remove the old blind nuts then install a new ply plate under the old one into which I could put m5 or M6 nuts. So, what I found was, as expected, it is not too difficult to dismantle anything that's been epoxied using heat then pressure/prising. This was how I dismantled much of the oil soaked nose in the first place. First I tried inserting a metal bolt and heating that with a hot air gun at 150 Deg c. No joy! Secondly I got my old Antex soldering iron that I keep for melting foam. With no tip I could insert this into the nut and after about 30 seconds start pressing on the edge of the nut from above. Soon it popped out cleanly. So now I have made a new plate and clamped the wing in place to use a 3mm drill bit to mark the position and angle of the new nuts in the tacked in place plate posioned below the original. Removing the new plate then drilling out to 4mm then I was able to check with spare M4 nylon bolts that the new plate works (just screwing the bolts through the old holes and into tight hole in the new ply). This worked well. Now when the new nuts and bolts arrive I'll reassemble with new epoxy. Job done hopefully! 2 Quote Link to comment Share on other sites More sharing options...
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