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Countersinking Mishap... Can I fix?

danielhv

danielhv

Well Known Member
So I was working on the Z brackets that connect the fuel tanks to the spars... I was counter sinking the holes where the rivets attach the platenuts. This is on the #6 Z-bracket (6th bracket from the root of the spar). I was drilling away, and leaned down to look at the progress, and accidently angled the drill off the edge of the bracket, thus making quite a large countersink. :eek: Any way to fix this? Leave it? What can I do?

IMG_2889.JPG
 
You can drill that and the nutplate up to a #30 rivet, all though you will loose the edge distance on the nutplate, but remember for the most part that all those rivets do is hold the nut so you can screw it.

Build on,
Steve
 
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Daniel - When I did my Z-brackets I found it much easier to line up 2 of them next to each other braced on a piece of wood 1x2 when doing the last hole at each end. That should prevent problems countersinking.

As Steve said, the rivets just keep the nut from turning. Maybe it would be ok to use some JB as filler under the rivet, and allow it to harden before setting the rivet? Others may be able to better comment if JB or some other filler would be acceptable here.
 
The fastener threaded into the nutplate carries the load in this case. The rivet affected by this only serves to keep the nutplate in place when the bolt isn't there. So, from a purely structural point of view, you have no problem.

See if you can sub a 1/8" rivet here instead. It should come close to filling in the csink hole.
 
Squeeze it as is and move on. As stated earlier that rivet only holds the nutplate in place.
 
I second that...

JB weld it up, once hard, sand smooth and re countersink it.

You will never know its there after that fix....


What concerns me more than that are the chatter marks around the bolt hole... What kind of debur bit are you using?
 
As others have said, this rivet just holds the nut-plate from turning. Don't worry about it. Build on.
 
I found that using too much pressure deburring caused that. I also second the fill and redrill method, except I use blue Hysol.
 
I had tons of problems with the Avery 3 flute leaving chatter marks to the point that I stopped using it.

Bob sent me a 6 flute for free and it solved that problem. My original 2 flute also did not chatter.

The 3 flute works great on fiberglass and steel but I do not use it on aluminum due to the chattering. Chattered hole chamfers are just asking for stress risers and cracks.

danielhv said:
http://www.averytools.com/pc-73-43-speed-deburring-tool.aspx

It only seems to leave the chatter marks on larger diameter holes...
Click to expand...
 
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