J

jazzbazzfazz

Member
I've gone over the SB06-2-23 and am puzzled (I'm also new to safety-wiring).

The bulletin describes drilling a hole for the wire in the AN818-6D coupling nut, but never the orientation of the hole. Does the hole run through adjacent faces in the nut (never actually passing through to the inside of the nut, but running outside-to-outside so to speak)?

If so, does it compromise the strength of the nut much? Is there a jig available to "foolproof" the drilling procedure?

Would I do just as well to proseal the nut to the tube after it's torqued?
 
Flop Tube SB

jazzbazzfazz said:
I've gone over the SB06-2-23 and am puzzled (I'm also new to safety-wiring).

The bulletin describes drilling a hole for the wire in the AN818-6D coupling nut, but never the orientation of the hole. Does the hole run through adjacent faces in the nut (never actually passing through to the inside of the nut, but running outside-to-outside so to speak)?

If so, does it compromise the strength of the nut much? Is there a jig available to "foolproof" the drilling procedure?

Would I do just as well to proseal the nut to the tube after it's torqued?
Click to expand...

Here is what we did. Van sells the anti-rotation bracket, or you could fabricate one of your own. Hope this helps.

sbfloptube.jpg


Regards,
 
Special Drill Jig

Avery and others sell a special jig for drilling locking wire holes in hexagonal nuts and bolt heads. I cant imagine how you'd do it without one - unless you had a mill and even then the drill bit would wander. OK perhaps with some careful center punching, a vice and drill press :)

Jim Sharkey
 
You can do it

When I got the service bulletin, I was concerned about the same issues. but it really wasn't a big deal.

I first marked the flats of the tubing nut that needed the safety wire, then took the tubing off so I could clamp it at the drill press. After center-punching, I used a 1/16" drill bit--drilling perpendicular to the flat until the hole got started. Then I unclamped and reclamped the nut 45 degress over so that the through hole could be drilled. It drilled through pretty quickly and it didn't eat into the threads or break through where the flats meet (at the apex). You can practice on a spare tubing nut first to prevent screwing up the one on your fuel pick-up tube if you'd like.

If you have a jig, it would probably make a cleaner hole. But you can do it without one.
 
I wasn't happy with the fuel pickup tubes I made (internal burrs and generally poor appearance) so I bought a pair from Vans. They have a filter screen installed and the B-nut is already drilled for the safety wire.
 
I purchased the pick up tubes from Vans about six weeks ago and the B-nuts were not drilled. Not that hard to do with the right tool just go slow when drilling.
 
I installed mine post SB......

but installed the nuts with Locktite. That seemed logical to me, at the time, since I would not be able to get to them or inspect them anymore later on. I never bothered about the safetying after that.

If you still have to do your tanks, you may want to stick to what Vans tells you to do.

Regards, Tonny.

PS: use this information at your own risk!
 
D-Dubya said:
... After center-punching, I used a 1/16" drill bit--drilling perpendicular to the flat until the hole got started. Then I unclamped and reclamped the nut 45 degress over so that the through hole could be drilled.
Click to expand...

That's exactly the technique that has worked for me in the past, Although I used a #50 and didn't bother re-clamping.

However I won't be bothering - I don't want to start a war here, but the SB was as result of people not tightening their fuel pick ups. We don't safety wire any other pipe fitting and they don't come un-done, so why is this one special? As someone else suggested, Pro-seal would probably be a better technique and wouldn't be modifying a standard part in a critical location (not sure loctite would stand up to immersion in fuel).

Only my view, for what is worth.

Pete
 
For you informations, this is what came in my wing kit (bought 6 months ago)

DSC04540.JPG


I've got four of them. 2 of each model (2 model, only change is the pattern. It's rotated half a notch on the 2nd model).

It does 2 things : prevent the angle fitting to rotate and prevent the nut from coming loose.
 
Fuel Tank Tube SB

The SB says fuel tank components shipped prior to 2/23/06. My kit was shipped after this and has the hex anti-rotation brackets. Do I need to safety wire the nut?

Thanks,
 
pilot28906 said:
The SB says fuel tank components shipped prior to 2/23/06. My kit was shipped after this and has the hex anti-rotation brackets. Do I need to safety wire the nut?

Thanks,
Click to expand...

If you have the same anti-rotation bracket as me, you don't need to safety wire anything.
 
hex anti rotation bracket

I closed my right tank today. I had installed the hex anti rotation bracket and did not safety wire eventhough the vans pick up tubes had holes for wires. There is no way the nut can turn.
i did notice the hex anti rotation bracket sat a little away from the inspection cover when inserted into the nut. I had to make little plates out of sheet metal and drilled rivet holes through them and riveted the anti rotation bracket to the inspection cover with plates in the middle. Had to pro seal it all. was messy. The plate i made kept on wanting to slide off.
 
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