Wing spar question

JohnR · Post by **JohnR** » Thu Mar 30, 2006 1:05 am

Well I started on the right spar tonight and got all of the nutplates for the tank attached. I'm going ot use Vans method of countersinking the #8 screw holes with the nut plate as a guide. I tried one and it seemed to work great.

The question is that I have seen where the countersink should be .365-.375 in diameter when done. I ran my test one in .370 and it seems really deep. I double checked my info and the numbers are correct. Just thought I would get a little input from the group here.

captain_john · Post by **captain_john** » Thu Mar 30, 2006 6:41 am

I think people dwell into this minutia too deeply. I never measured mine. The standard method of making a sample skin the same thickness of the tank and inseting it into the recess seemed to do just fine for me.

I have seen that Van has fueled this confusion by publishing specs on how this countersink should measure up. I think this is fine, but the bottom line is the skin needs to fit into the recess of the countersink.

Make a sample dimple and fit it to the countersink.

CJ

JohnR · Post by **JohnR** » Thu Mar 30, 2006 8:04 am

Thanks CJ, that is what I decided to do. ALways good to have another voice tell you it is the right thing.

jim_geo · Post by **jim_geo** » Thu Mar 30, 2006 12:28 pm

I had the same question about how deep to counter sink for a dimpled skin to fit and the tech person at Vans told me that they were adopting the spec that you counter sink until the rivet fits flush or just slightly below the surface. The tech actually quoted some number of thousandths suffice it to say slightly.

Dan A · Post by **Dan A** » Thu Mar 30, 2006 8:44 pm

Why make such a fuss over the diameter of the hole? All you need to do is take a piece of scrap aluminum sheet of the same thickness as the skin and dimple it with a #8 dimple die and use it as a template. When the template will set flush on the spar the hole is the correct size. Make all the others the same and your tank skin will fit flush.

Dan

jim_geo · Post by **jim_geo** » Thu Mar 30, 2006 10:24 pm

Really......Flush?

Wicked Stick · Post by **Wicked Stick** » Thu Mar 30, 2006 10:26 pm

Dan A wrote:Why make such a fuss over the diameter of the hole? All you need to do is take a piece of scrap aluminum sheet of the same thickness as the skin and dimple it with a #8 dimple die and use it as a template. When the template will set flush on the spar the hole is the correct size. Make all the others the same and your tank skin will fit flush.
Dan

Dan and the Capt'n are right on here.. The key word is using the same thickness on the dimple template that matches the skin that will go into the countersink.

JohnR · Post by **JohnR** » Thu Mar 30, 2006 11:09 pm

After thinking about it I realized I had missed the obvious and just needed to dimple a piece and make the dimple fit. As mentioned above.

I didn't get a chance to work any today and won't be able to tomorrow but hopefully this weekend will be able to get back to it.

Thanks eveyone for the replies.

RivetBangers.com

Wing spar question

Wing spar question

Thanks all!