NorthernRV4
Well Known Member
I am ready to countersink the skin rivet holes in the main spar flange on my -4 spars and I'm going in circles on whether to machine countersink or dimple countersink the holes. Tech Support said it wouldn't matter from a structural standpoint to do it either way. I've already dimpled my aft spar flanges with good results but I can't really comment about possibly distortion since I have not mated my wing skins (yet to be dimpled) to them again.
I'm leaning toward dimpling the main spar flanges (.040") with my pneumatic followed by a hand squeezer to crisp them up. If I need to touch them with a microstop after that to remove a thousand or two then I can. The main reason I'm leaning this way is that I find the skin dimple nests into a dimpled substructure better than a machine c/s even when machining .006-.007" deeper than flush as per Van's instructions. The newer kits are all thicker flanges so dimpling is out of the question and there is many a thread about machine c/s these.
Anyone have some advice?
I'm leaning toward dimpling the main spar flanges (.040") with my pneumatic followed by a hand squeezer to crisp them up. If I need to touch them with a microstop after that to remove a thousand or two then I can. The main reason I'm leaning this way is that I find the skin dimple nests into a dimpled substructure better than a machine c/s even when machining .006-.007" deeper than flush as per Van's instructions. The newer kits are all thicker flanges so dimpling is out of the question and there is many a thread about machine c/s these.
Anyone have some advice?