Dimpling rear wing spar top flange

I am working on the rear wing spar and have gotten to the point where they have you dimple the holes on the top flange adjacent to where the doublers are. Because of the angle the top flange is bent, it interferes with the dimple die/yoke, and causes the flange to bend open a bit. As far as I can tell, it looks to be about 4 degrees or so difference.

Any suggestions on how to prevent this? I have the tight fit dimpling tool from cleaveland that should work, but was really hoping to use my tank dies to get a little bit deeper dimple.

Steve,
You can grind one side flat on dies.
Will use a lot like that.

Dimple and then check piece with square.
Normal if it bends out slightly.
Just keep checking square.
Hand seamers will also work getting piece back to square.

Hope it helps.
Boomer

I thought about that but it might be the yoke that's touching. Will take a closer look in the morning

My vote is that it is the yoke that is touching, which you could theoretically grind the corner off. It is important that you get this flange back to the correct angle, otherwise once you have put the skin on and then discover that it needs tweaking, then you have to cut a slot in a piece of hardwood and use it as a tool to bend the flange. It is a slow and time consuming process compared to getting it right before you put the skin on. Don't ask me how I know this...
Cheers,
Tom.

You're not alone

I had a similar issue. I agree, Its the yoke that interferes.

Ideally it would be best to have a sacrificial yoke to grind down, but they are quite expensive. For my wing, I used my vice grip dimpler. I made a few passes, it took forever and my hands hurt. But considering that the plans want you to ever so slightly machine countersink the dimple, it worked pretty good. (not as good a the pneumatic squeezer though)

http://garetsrv.blogspot.ca/2016/07/little-more-debur-countersink-and.html

I just finished riveting the skin/rear spar and it looks fantastic by the way!

OK, thanks guys. Fortunately I have only dimpled the 3 places adjacent to the doublers...on one spar. Guess I will use the tight fit dimpling fixture for the rest of them.

Quick update: I ended up grinding down the nose of the yoke...just enough to clear the spar web and keep it from touching. Worked great!

On the first spar, I used seaming pliers to bend back to original position, and that worked fine also.