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No room for the countersink cage

OrenAir

Active Member
I'm supposed to countersink #30 the rudder stops, although there's no way the cage can fit inside that angle. How do you do this step?
 
Most people obtain a second cage and cut away one side.
Another option is to remove the cage and carefully "freehand" the countersink.
 
Everyone has that problem. You have decide what is right for you. I think I wound up taking the CS bit and putting it on my deburring tool and hand cranking that. Not show quality, but certainly acceptable. Those rivets were a little difficult to set too, can't get the head of your flush mount rivet set in there. I wound up using a flat piece of steel and using that between the rivet and the flush mount rivet set.
 
I used my hand deburring tool for these. You will find other areas where this tool will work nicely for the countersink.
 
+2 to hand deburring tool ... once I got some practice I found myself going for this tool vs the drill and cage as it was more convenient, especially on fiberglass.
 
Hand deburring like the crowd. But this might be a good time to get a 1/4" shaft single hole deburring tool. You can use it on the plexiglass later. It will leave a nice smooth, concentric CS.
 
I use a variable speed drill and a countersink bit for almost all my countersinking needs. I keep the drill speed very slow and just keep checking for correct depth with a rivet. After several, I normally can get the proper depth after a couple checks.
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Wish I saw this a few days ago. I figured out how to CS by hand with a deburring tool. Came out ok. Happy to say, i use a cage on all my other CS work.

One quick note, If you use a back rivet set on the manurfactured head of that rivet, use electrical tape on the manufactured head and push real hard. Or, your manufactured head will bulge up.
 
I've been hand drilling the countersinks in my cowl using some carbide-burr countersink bits with great results. Go slow, and check often. All have come out just right.
 
How about something like this
new-guy-001.jpg
 
Yep. I call it kamikaze counter sinking or dimpling. Free hand can liberate you from the cage :). Just be darn sure you can meet your quality assurance expectations before ruining a part. The other such operation is a dimple die in the rivet gun and it's companion in a backing buck. Do you feel lucky? :) <smily face fully implied!>

Once you get over the pressures, angles, and all the ways this could go wrong, you'll be moving right along without so much jig analysis. I know a Boeing production engineer would be squirming in his seat, but we aren't build a space shuttle here.
 
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