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Rod end edge distance?

planejus

planejus

I'm New Here
Today I constructed the pushrod for the elevator on my RV-7. when checking for the edge distance for the rivet holes on the rod ends, I realized that I don't recall doing that for the aileron pushrods that I fabricated a long time ago. Now I am wondering. From my build log I had primed the inside of the rods one day, and later riveted the ends on. I am wondering now If I ever pulled the ends out and looked at them after drilling, or just stuck rivets in them as I drilled. I don't remember measuring for edge distance on the end; just tucking them the the tube for a slight lip like depicted on the drawings. I really can't remember, but I want to know that my rod ends are secure. The ends are tucked inside the tubes just a little, but is it enough to have good edge distance on the rod ends that I can't see now. The edge distance on the tube is right at double the rivet diameter. I probably centered the rivets in the flat portion of the rod end. Does anyone have theirs out and have looked at them? Do these look like they are tucked in enough? Do I make new ones just so I know? Or am I being too critical? This is my first build and I am figuring it out. Thanks!
Here is a pictur from by build log when I drilled them.
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I know the feeling.. To assure yourself that you have the correct edge distance, make a tool using safety wire with a small 90 degree bend at the end. Insert the wire into the rod end and find the edge of the insert. Mark the safety wire and remove it from the end. Lay it on the outside. Now you know where the end of the insert is and you can measure your edge distance.
 
Not trying to add fuel to the fire, but this reminds me of something one of our EAA Tech Counselors shared with us. He was inspecting a plane that was almost finished and he thought those main pushrod ends didn't look right. He gave the pushrod a tug and the end fitting pulled right out. The rivets weren't even partially in the fitting. While that doesn't appear to be the case with yours, your concern is valid. From what I can tell, yours looks right.

Bill suggested a good trick to measure that depth. But because of the way that part is machined, you may have trouble grabbing the internal lip of the fitting and getting an accurate measurement. Maybe someone can measure the overall length of that fitting on their kit that hasn't been assembled and report back..
 
Those are fine. As I recall, the cylindrical portion of that rod end is about 1/2' long. Might want to have somebody who has one on the shelf measure to find out exactly just for your own comfort level.

The actual issue will be if you cut the tube length to the dimension on the print there's a good chance they will be too short to get the minimum required depth on the helm joints when you go to install them. The dimensional callout on the print for that thing doesn't take into account any tolerance buildup or sticking that cone in too deep when you rivet it. to the tube.
 
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From the edge of the tube to the end of the cone measures 1.125". Rivets are .25" back from edge. Yours look good. I agree with Terry above, there should be 1/2" inside the tube so hopefully someone can verify for you.
A
 
From what I remember, "flat" part of the aluminum fitting (VA-111) is exactly 1/2". So if you place it right at the edge of the tube, and drill a hole at exact 0.250" edge distance from the edge of the tube, you will get exact 1/2" edge distance on the fittings.

Two things that work in your favor:

1. If you push fitting slightly inside of the tube (like you did), and locate holes 0.250" from the edge of the tube, you gain some edge distance on the fitting.
2. The minimum edge distance for these rivets (don't trust me on this one) is 0.219" -- you can search the forum (see this, for example) & also ask builders support.

P.S. My pet peeve is how non-human friendly RV-7 plans sometimes are. They would specify an angle with something ridiculous like 24-5/32" just because CAD calculated this length with exact 0.250" edge distance at each end (well, this is my speculation)... Just make it 24-1/4", trim if doesn't fit :D Same for pushrods -- you can absorb some extra length simply by screwing fittings in, so why not err on a side of making them longer?...
 
idubrov said:
From what I remember, "flat" part of the aluminum fitting (VA-111) is exactly 1/2". So if you place it right at the edge of the tube, and drill a hole at exact 0.250" edge distance from the edge of the tube, you will get exact 1/2" edge distance on the fittings.

Two things that work in your favor:

1. If you push fitting slightly inside of the tube (like you did), and locate holes 0.250" from the edge of the tube, you gain some edge distance on the fitting.
2. The minimum edge distance for these rivets (don't trust me on this one) is 0.219" -- you can search the forum (see this, for example) & also ask builders support.

P.S. My pet peeve is how non-human friendly RV-7 plans sometimes are. They would specify an angle with something ridiculous like 24-5/32" just because CAD calculated this length with exact 0.250" edge distance at each end (well, this is my speculation)... Just make it 24-1/4", trim if doesn't fit :D Same for pushrods -- you can absorb some extra length simply by screwing fittings in, so why not err on a side of making them longer?...
Click to expand...
I agree with you on that. After making the ailerons, I made my elevator tube longer. I want to know I have a lot of threads inside the rod 😎
 
Bill.Peyton said:
I know the feeling.. To assure yourself that you have the correct edge distance, make a tool using safety wire with a small 90 degree bend at the end. Insert the wire into the rod end and find the edge of the insert. Mark the safety wire and remove it from the end. Lay it on the outside. Now you know where the end of the insert is and you can measure your edge distance.
Click to expand...
Great Idea! I will do this.
 
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