How do I do this?

aarvig

Well Known Member

• Apr 23, 2015

• #1

I am countersinking the main spar for a 426 rivet that mounts flush on the front of the spar and holds a tank attach plate nut on the aft side of the spar. My countersink won't fit into two of the plate nut holes as they are to close to the main spar flange. How do I countersink those holes?

 

YellowJacket RV9

Well Known Member

Patron

• Apr 23, 2015

• #2

I did it (very carefully) without a countersink cage, using the right angle drill attachement.

 

rmartingt

Well Known Member

• Apr 23, 2015

• #3

 

wirejock

Well Known Member

• Apr 23, 2015

• #4

Countersink

Put your countersink cutter in your deburring tool and turn it by hand.

 

aarvig

Well Known Member

• Apr 23, 2015

• #5

Thanks all y'all! Jobs done!

 

RV7A Flyer

Well Known Member

Patron

• Apr 23, 2015

• #6

I cannibalized a countersink cage, cutting off one side for situations which required close-in countersinking. I believe you can also buy smaller diameter cages, but the one-sided cage always worked fine for me. On a few occasions, I did countersink (carefully) with no cage (and as noted, usually with the angle drill adapter).

 

claycookiemonster

Well Known Member

• Apr 27, 2015

• #7

Also...

Most of these replies have implied it, but: if you're using a countersink without the usual support, a high speed air drill probably won't be your friend! It can develop a tragic wobble before you realize it. Go slow here, either hand turned or the old school electric variable speed drill you put away

 

Wunderon

Well Known Member

• Apr 28, 2015

• #8

handheld 6 flute slow

http://www.averytools.com/prodinfo.asp?number=79025