[lucaperazzolli]

Ciao to everybody !

I'm match drilling my bottom wings skin. At the main spar there are a beautiful green painted countersink rivet holes.Do I have to match drill the skin through these holes in the main spar #40, or with #41 is better, or there is a particular action to do ?

...... Arghhhh

 

[rv9av8tr]

I match drilled my QB wings with #40. I also had to re-countersink a number of the "pretty green holes" because many weren't deep enough to fully accept the skin dimples.

 

[Camillo]

Ciao, Luca.

I disregarded match drilling such holes. Your thread makes me think if I did the right choice...

 

[jmartinez443]

Ciao, Luca.

I disregarded match drilling such holes. Your thread makes me think if I did the right choice...

I didn't match drill the holes along the spar in my QB. I think you are likely to do more damage than good by redrilling the countersunk holes. I figure if the rivet fits and the prepunched skin holes match up there is no need to. I was also concerned about introducing stress risers on the spar.

This is just my feeling. I'm no expert.

 

[rv9av8tr]

Wing Spar countersinks

Keep in mind, these countersinks have to be deep enough to allow the dimpled skin to fit flush. It takes a deeper hole than what it takes for just a rivet head to fit flush.... otherwise the skin will not fit properly. Trial fit a scrap piece of the same thickness as the skin, that you have dimpled to make sure the countersink is the correct depth.

 

[Rupester]

What Mike said. Exactly the procedure I use.