Counter sink angle?

I wish I could find the reference to 82 degree angles for Countersink but I cant and following a discussion with the good people at Cleveland tools I understand that ALL aviation countersinks are 100 Degrees. In assembling the Vertical Stabilizer the plans call for counter sinking the stiffener. I did that but using an 82 not a 100. is this an issue?
Thanks

You should be able to countersink it with a 100 degree now to bring it to the right angle without over-countersinking it.
It needs to be 100 degree to match the angle of the flush rivet heads.
However, If you countersunk it using the 82 degree until the rivet was flush and if you now try to do 100 degree then the hole will be over-countersunk

Countersink Angle

Bob Avery sells 82 degree, 100 degree, and 120 degree countersinks. The 120s are used with the Avex pulled countersunk rivets.

Jerry Folkerts

110 deg

In watching an old WW2 rivetting lesson on youtube the Instructor stated that the bottom sheet must be dimpled to 110 deg to receive the 100 deg dimpled top sheet. Same if you were dimpling top sheet and countersinking bottom sheet. Anyone else seen this and does it still hold true?

salto said:

In watching an old WW2 rivetting lesson on youtube the Instructor stated that the bottom sheet must be dimpled to 110 deg to receive the 100 deg dimpled top sheet. Same if you were dimpling top sheet and countersinking bottom sheet. Anyone else seen this and does it still hold true?

Click to expand...

Yes and no. The issue is that no dimple is a perfect V, and the top and bottom of the dimple are not always parallel, there is some radius of curvature near the edge. So in principle the bottom dimple or CS neads to be a bit wider. For RVs, with relatively thin skins, using the same dimple tool top and bottom works okay. For thicker pieces where you might want different sizes top/bottom, RVs usually go to countersinking the top piece.

110deg

Thanks Bob plenty of evidence out there that supports what you say.