Re: Cotton Waiex 191 - N191YX
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So here is my technique for drilling the critical 1/4" tail hold down holes. First I took out the rivets at the front corners of the shear panel (by the green arrows).
![Image](http://i198.photobucket.com/albums/aa72/Aerowerk/BCF7AEF9-6E94-44E6-B59E-7372AC82F1CE.jpg)
Then I clecoed down my tail mount angle, put a scrap piece of angle behind, and clamped them together:
![Image](http://i198.photobucket.com/albums/aa72/Aerowerk/145D6068-BAB0-4300-86C9-FE8D4DDD583B.jpg)
Brought the two angles over to the vise and transferred the holes using my 3/16" HF transfer punch:
![Image](http://i198.photobucket.com/albums/aa72/Aerowerk/3AEAF4D2-9E1B-4832-BF90-6AF3D7C14B4C.jpg)
I shot those 6 holes on the drill press, clecoed the angles back together, and clecoed them down using the two holes that want to become 1/4" tail hold downs. I then transferred the holes from the spots where I removed the rivets. That scrap angle now becomes a tool to hold the lower tail mount angle:
![Image](http://i198.photobucket.com/albums/aa72/Aerowerk/CADB82EF-E331-49FF-A6E0-D24B68A22087.jpg)
Here are all the clecoes in:
![Image](http://i198.photobucket.com/albums/aa72/Aerowerk/24F8B91B-58CD-4B93-A1AB-B0B16E2F09E8.jpg)
Now I bring up the hole in the block and angle to the next size. In this case I am going from #40 to #30:
![Image](http://i198.photobucket.com/albums/aa72/Aerowerk/CAB09112-0AAA-4CB0-B68C-8BF7D7DA3ADC.jpg)
The block and angle now act as a 1" thick guide block to drill the longeron, shear panel, and the angle underneath.
![Image](http://i198.photobucket.com/albums/aa72/Aerowerk/EBE8461A-4B00-4936-BD14-88CC6B8D5474.jpg)
It's almost too easy. For all these holes I have been averaging one hour per hole to final size. Much better than rebuilding the tail. Almost forgot to mention, I used some aluminum pops to rivet the shear panel to the angle underneath temporarily. The angle is clecoed to the verticals underneath. I will take the angle out to deburr then it goes back in for keeps.
![Image](http://i198.photobucket.com/albums/aa72/Aerowerk/BCF7AEF9-6E94-44E6-B59E-7372AC82F1CE.jpg)
Then I clecoed down my tail mount angle, put a scrap piece of angle behind, and clamped them together:
![Image](http://i198.photobucket.com/albums/aa72/Aerowerk/145D6068-BAB0-4300-86C9-FE8D4DDD583B.jpg)
Brought the two angles over to the vise and transferred the holes using my 3/16" HF transfer punch:
![Image](http://i198.photobucket.com/albums/aa72/Aerowerk/3AEAF4D2-9E1B-4832-BF90-6AF3D7C14B4C.jpg)
I shot those 6 holes on the drill press, clecoed the angles back together, and clecoed them down using the two holes that want to become 1/4" tail hold downs. I then transferred the holes from the spots where I removed the rivets. That scrap angle now becomes a tool to hold the lower tail mount angle:
![Image](http://i198.photobucket.com/albums/aa72/Aerowerk/CADB82EF-E331-49FF-A6E0-D24B68A22087.jpg)
Here are all the clecoes in:
![Image](http://i198.photobucket.com/albums/aa72/Aerowerk/24F8B91B-58CD-4B93-A1AB-B0B16E2F09E8.jpg)
Now I bring up the hole in the block and angle to the next size. In this case I am going from #40 to #30:
![Image](http://i198.photobucket.com/albums/aa72/Aerowerk/CAB09112-0AAA-4CB0-B68C-8BF7D7DA3ADC.jpg)
The block and angle now act as a 1" thick guide block to drill the longeron, shear panel, and the angle underneath.
![Image](http://i198.photobucket.com/albums/aa72/Aerowerk/EBE8461A-4B00-4936-BD14-88CC6B8D5474.jpg)
It's almost too easy. For all these holes I have been averaging one hour per hole to final size. Much better than rebuilding the tail. Almost forgot to mention, I used some aluminum pops to rivet the shear panel to the angle underneath temporarily. The angle is clecoed to the verticals underneath. I will take the angle out to deburr then it goes back in for keeps.