Golf Echo
Active Member
Dear =VAF= Brain Trust,
I had some minor frustrations in the countersinking of my first part (HS-710) to accept the 1/8" dimpled spar and an AN426AD4-6 rivet. It appears this was actually due to not squeezing the dimple dies quite enough. Regardless, I'm left with a countersink which is too deep. Deep enough to require a new HS-710? I dunno... that's a topic for another thread (and probably a question for Van's).
In any event, the "guess and test" method failed me. The Van's manual says "a couple of clicks", or "about 0.005" below the surface". I figure there has to be a better way to at least ballpark the depth the rivet should sit below the surface if dropped into the countersink. Here's my go at deriving a ballpark depth (d) based on skin thickness (t) and a countersink angle of 100?.
So, given a skin thickness of 0.032" (HS-702 spar thickness), the calculation says the rivet should sit approx. 0.010" below the surface if dropped directly into the countersink in order to get a perfect[ish] fit.
Make sense? Has anybody done/used something similar as a starting point?
I had some minor frustrations in the countersinking of my first part (HS-710) to accept the 1/8" dimpled spar and an AN426AD4-6 rivet. It appears this was actually due to not squeezing the dimple dies quite enough. Regardless, I'm left with a countersink which is too deep. Deep enough to require a new HS-710? I dunno... that's a topic for another thread (and probably a question for Van's).
In any event, the "guess and test" method failed me. The Van's manual says "a couple of clicks", or "about 0.005" below the surface". I figure there has to be a better way to at least ballpark the depth the rivet should sit below the surface if dropped into the countersink. Here's my go at deriving a ballpark depth (d) based on skin thickness (t) and a countersink angle of 100?.
![countersink%2520math.jpg](/community/proxy.php?image=https%3A%2F%2Flh5.googleusercontent.com%2F-9aZm9nRv364%2FUOCTTuTCEQI%2FAAAAAAAAACs%2FBYz9P3caa1s%2Fs640%2Fcountersink%252520math.jpg&hash=1d5b0835b490713e6f50a5020b9b1604)
So, given a skin thickness of 0.032" (HS-702 spar thickness), the calculation says the rivet should sit approx. 0.010" below the surface if dropped directly into the countersink in order to get a perfect[ish] fit.
Make sense? Has anybody done/used something similar as a starting point?