Van's Air Force
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Size of wing root and tip screws on a 6?
- Thread starter dmat
- Start date
az_gila
Well Known Member
But a lot of folks went to 6-32 on the tip screws because they are harder to strip in service.
The plans actually call for CS4-4 rivets.
DrillBit
Well Known Member
I remember a post (haven't tried to find it) that advocated 8-32 as the minimum size screw to use anywhere on a plane. Too easy to strip the head and/or torque off the head, the poster said.
I read that, of course, after installing the 3.14 billion (give or take a few billion) 6-32 platenuts on my tips.
I always use a "sacrificial screw" or three to hold a platenut in postion when match drilling the rivet holes and installing them. Takes longer, but eliminates eccentricity of the platenut threads with respect to the screw hole, and it means the platenut has been "stretched" so subsequent screws don't endure virgin platenut torque. (Can you say that on a family forum?)
The sacrificial screws are dunked in Boelube of course...and they are "sacrificial" only in it being almost certain, reusing the same screw over and again, that the head will be stripped.
Grab another 6-32 screw when one is even slightly stripped. Life if short, screws are cheap.
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fixnflyguy
Well Known Member
What I did..
I made every single screw on my -4 the same (8-32) and used reduced 100 degree head titanium screws (Boeing BACB30VF series screw). These screws have same head diameter as a 6-32 screw but an 8-32 shank. I used the same thing for fairings,wingtips,panels,cowling, interior panels, ect. This way, I don't have to keep inventory of several sizes, and the titanium is light and corrosion resistant. I also use reduced diameter stainless skin washers on all the exterior items. Small, light and tidy.
I made every single screw on my -4 the same (8-32) and used reduced 100 degree head titanium screws (Boeing BACB30VF series screw). These screws have same head diameter as a 6-32 screw but an 8-32 shank. I used the same thing for fairings,wingtips,panels,cowling, interior panels, ect. This way, I don't have to keep inventory of several sizes, and the titanium is light and corrosion resistant. I also use reduced diameter stainless skin washers on all the exterior items. Small, light and tidy.
az_gila
Well Known Member
I helped a new RV-10 owner (non-builder) put air in is tires 2 nights ago - working in his hangar with minimal lighting.
It seemed that the 8-32 screws connecting the front and rear portions of the wheel pants easily got mixed up with the few 6-32 screws that hold on the lower gear leg fairing.
It made me decide to simply use all 8-32 screws on a single assembly, such as a wheel pant, when I get to that part of my -10 build. Using two sizes doesn't bother me much, but keeping one size per assembly is a maintenance help.
I'll take the few grams weight hit.
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az_gila
Well Known Member
I don't in normal lighting.... but I noticed the non-builder owner had a lot of trouble identifying the difference.
Sometimes little changes make things easier for the next owner of the plane you built.
PS - The later plans (-7) don't specify the Cleveland 4-40 screws, they use 6-32 screws as an option to the CS-4 rivets.
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