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Dimensions of #6 screw countersinck

WVM

Well Known Member
Hi,

What are the outside dimensions for a #6 screw countersinck? For the #8 screws on the wing spar I found a value between 0.365 and 0.375 inch in various blogs and posts. This worked out fine (used 0.370 inch).
An very old post on this forum mentioned less than 0.3125 inch for a #6 screw countersink hole based on a discussion that followed on the first RVator release. But I cannot find confirmation for that value. For your information I am countersinking the #6 screws for the wing inspection plates on an RV-9.

I just wonder why VANS is not listing those dimensions in the manual because to me this is much more accurate than saying "use a test piece and see if it fits". Measuring is always and everywhere the same. If you drill to deep it will also fit with that test piece technique... but it is obviously not good.
 
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Thank you Mudfly! Clearer than this is impossible.

I once asked VANS during a Q&A at OSH if they plan to implement improvements from the RV14 into the earlier models. Their answer was: No. But if I see this manual of the RV14 I am really jealous! This would saved me hours of searching and reading to get confirmation on this silly problem.
 
Interesting -- I've never measured a CSK per se and don't understand why you feel the need for a numerical value. Initially, using a microstop, I'd dial it in by starting shallow and using a screw to check the depth. I bought multiple used mircostops from the Yard Store (around $15 each IIRC) and set them up with different CSKs (#8, #30, #40, etc) so I only had to get the depth set once. Truth be told, on the rivet CSKs I did so many that I eventually I could just eyeball it like I could for the rivet shop head and know it was good.
 
Interesting -- I've never measured a CSK per se and don't understand why you feel the need for a numerical value. Initially, using a microstop, I'd dial it in by starting shallow and using a screw to check the depth. I bought multiple used mircostops from the Yard Store (around $15 each IIRC) and set them up with different CSKs (#8, #30, #40, etc) so I only had to get the depth set once. Truth be told, on the rivet CSKs I did so many that I eventually I could just eyeball it like I could for the rivet shop head and know it was good.

Not everyone is the same. I prefer a number that I can measure, you prefer to do it on feeling. This is what makes us unique. But I feel, based on the many topics on this and other forums and blogs, that the older plans need an update. It may be obvious for some, but it isn't for others. In addition I don't have access to all these different tools as we use a metric system. Buying and shipping it expensive (add 25-30% + shipping). A simple copy paste from the RV14 plan to the RV9 plan of this CAD drawing would have saved me hours that I could have used on building my aircraft rather than surfing the internet. :)
 
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