Wing Strut Bearing

[ackselle]

Guys,

The picture below is of the wing strut bearing...bent! So.... I think the threaded rod is welded into the strut tube, and it's just mild steel. My thoughts are to drill out the threaded rod (1/4"), tap 5/16 into the rod and replace the rod end bearing with a male bearing with 5/16 thread.

Thoughts?

[HighWing]

Sounds like a plan. A couple of thoughts, though. I checked mine and the threads on my 1992 Model IV are 5/16". The other thought would be to check the thickness of the plate covering the end of the lift strut for enough threads for strength.

[ackselle]

Thanks Lowell,

Absolutely correct..... the current threaded rod is 5/16....was thinking of going to 3/8

[ackselle]

Can anyone out there confirm if the threaded rod at the top of the strut tube is welded into the strut tube? Or can I remove it and simply replace it with 5/16 threaded rod? Currently, it does not turn using a wrench on the bearing.

[kmach]

Sorry to see your problem.

Is there a story behind this ?

[ackselle]

Kevin.... yes, there is a story. We can talk about it if I ever get to the Shoal Lake fly in!

Cheers

[Dusty]

Hi ackselle
I posed a similar question a while back due to some light corrosion and got some very helpful replies.
It appears the thread is a weld in,probably not what you want to hear:eek:
Without measuring I am not sure there is enough metal to drill and tap in a replacement thread.
An ideal solution would possibly be to carefully remove the fitting and install a threaded longer slug to convert to a male rod end,if this happened again it would be a minor repair of simply replacing the rod end.

[HighWing]

Can anyone out there confirm if the threaded rod at the top of the strut tube is welded into the strut tube? Or can I remove it and simply replace it with 5/16 threaded rod? Currently, it does not turn using a wrench on the bearing.

Not sure, but somehow my memory is trying to suggest that the threaded end is something like what is in the Aircraft Spruce Link below.

http://www.aircraftspruce.com/catalog/appages/an490.php?clickkey=3027459

[Av8r3400]

Yes, Lowell. That is exactly what we have there on the lift strut.

Is the "incident" that damaged the current strut something that will happen again? If not, maybe rebuilding the strut as designed may be easier. Drilling and tapping that strut straight, in order to use a male rod end bearing, will be very difficult.

If you get replacement 5/16" rod end like Lowell linked to, you can use this to plan some careful cutting with a Dremel type tool to remove the old one in order to replace it. The strut will most likely need to come off the plane, so doing a circular cut may not be all that bad…

(I'd suggest replacing the female rod end bearing as it is probably damaged as well.)

[TJay]

Also with out adding a couple inches of tubing a male rodend will be way to short. You could cut the end of the strut off at a fish mouth shape and get a piece of solid 4130 about 4 inches long slide down into the tube a couple inches and weld it in there, then tap for a male rod end, that would give you the length and strength you need, That is kind of what I am doing, I bought these rodends from spruce GMM-4M-675 I would think they would be strong enough for your weights. Just my thoughts

[PapuaPilot]

It might be worth calling the factory and seeing what the cost of a new lift strut is. This is one part that you can't afford to question the integrity and strength.

It may be possible to remove and weld a new rod end, again I would consult with the factory and see what they recommend.

[jiott]

If I was going to repair rather than buy a new lift strut, I really like the idea of using that Aircraft Spruce threaded weld-in rod that Highwing linked to. Carefully cut out the old welded in plug and make a new one with a hole in it to fit the ACS piece and then weld this new assembly into the end of the strut.

[TJay]

If I was going to repair rather than buy a new lift strut, I really like the idea of using that Aircraft Spruce threaded weld-in rod that Highwing linked to. Carefully cut out the old welded in plug and make a new one with a hole in it to fit the ACS piece and then weld this new assembly into the end of the strut.


How does that work, the biggest one I see listed only fits a 3/4 inch .035 tube I am guessing this guy has 7/8 .035 tubes.

[HighWing]

I think what I would do is go with the original plan with modifications. I have a lathe, so that tool greatly influences my thinking. Find a friend or local machine shop and with a piece of 4130 rod, machine, drill and tap a plug that could be inserted into the lift strut after cutting out the existing fitting. By careful measurement and machining, a bit of the strut tube could be sacrificed for ease of removal of the existing threaded rod end and the plug machined to allow exact required dimensions for welding in place.

[ackselle]

Thanks Guys.... after "listening" to all your "advice"...The strut is coming off, going to a machine shop to get the repair completed by replacing the plug and rod...back to original.

Cheers,
Ackselle

[jiott]

TJay just to clarify my post: what I was trying to say was exactly what Highwing suggested-make a new plug to fit the lift strut ID, but instead of drilling and tapping just drill a smooth hole and use the weld-in ACS part.

[TJay]

TJay just to clarify my post: what I was trying to say was exactly what Highwing suggested-make a new plug to fit the lift strut ID, but instead of drilling and tapping just drill a smooth hole and use the weld-in ACS part.

ok that makes sense to me, does anyone know if these things are Mig or tig welded in.

[Esser]

I would guess mig

[catnipp]

I have a LE stud thats not in reliable condition as well all the rest are good! i was going to drill and tap depending how thick it ends up being inside the end of the tube. The trhreaded stud in the link looks ideal to drill the end and set it weld it in all the way around the tube end. but if there is enough meat in after drilling it out a stud with a jam nut should work. they say at leadt 5 threads in for it to be strong enough. $300 for entire new strut. but cant put a price on a life and being lift strut wellll it has to be done right! so i am in the same boat! one stud is bad! should be a way to fix this without major issues.??

[neville]

Don't know what model aircraft you have but on a SS7 model the threads of the lift strut ends are M3 threads not the common depth threads, for the purpose of higher strength.

[catnipp]

mine is a KF 3 with some 4 upgrades. The strut ends are the welded in stud type both front and rear on outbound ends. They are the 5/16x24 thread, same as AN5.

[neville]

woops, I have been working in metric In excess. I meant to say the threaded end of the lift strut used in an SS7 is tapped to H3 specs not M3. Find attached a data sheet explaining tap specs.

[catnipp]

Git it all done today. Turned out nice! Flew for a while today and that plane just does so good. soft flyer. Dont know how to post pix to show what I did to fix the end.