[Av8torTom]

With regard to the front spar of the vertical stabilizer - are people dimpling or machine countersinking the holes. Material seems kinda thin to countersink...

Thanks,

Tom

 

[agirard7a]

Dimple

Hi Tom. Not sure about the spar. But dimple
when you can much stronger on shear load.

Al

 

[Av8torTom]

0.032

Hey Al,

I just measured the thickness and it's 0.032 It dimples easily, but I'm concerned that the skin dimples won't nest together nicely without a slightly deeper dimple in the spar material.

T.

 

[videobobk]

"...slightly deeper dimple" translates into using a tank die (0.007" deeper) or a light turn with a single flute countersink. The tank die does wonders in some applications!

Bob Kelly

 

[aarvig]

Absolutely DIMPLE!!

I dimpled mine and they came out perfect. On .032 you can countersink but why? If you accidently go too deep with the countersink you have holes that are too wide. A dimpled joint is usually a safer bet when the metal thickness is on the margin. In fact, I called Vans and I was told to dimple those holes instead of countersinking them as well as to dimple the skin, spar, rib connections (three dimples stacked together) on that front spar. The rivet line is beautiful.
Have fun.

 

[Av8torTom]

VANS agrees

Dimple it is...

Thanks everyone.

Tom