Forums: Skydiving: Gear and Rigging:
Locktite on reserve links

 


baronn  (D 22387)

Aug 17, 2013, 5:53 PM
Post #1 of 10 (2093 views)
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Locktite on reserve links Can't Post

On the last 4 Sigmas I opened, all had loose screws on the reserve L bars. It was a 182 operation. I think locktite can solve this issue. UPT is telling me no, they don't endorse it. They tell me because they can't open them up if needed. 1st, the blue locktite comes undone. 2nd, even if it didn't, isn't that a good thing? Even if I had to take bolt cutters to them, I don't care. I would rather do that than risk having it come undone when I needed it. Can't think of a much scarier situation having 1 or more risers release on a reserve especially on a Tandem. Thoughts?


councilman24  (D 8631)

Aug 17, 2013, 8:26 PM
Post #2 of 10 (1944 views)
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Re: [baronn] Locktite on reserve links [In reply to] Can't Post

What's your definition of loose? 1/4 turn, 1/2 turn, 2 turns? The screws don't take the load, unlike a french link. They hold the halves of the l bars in place and the tenon in the hole takes the load. (The tapered nature of the tenons probably does transfer some load to the screws but nowhere near the whole load.) Unless they were at least a full turn, maybe two loose I wouldn't consider it unusual. I usually can take a 1/4 turn or so in most I open. Including ones I tightened last time. Both screws would have to be substantially out for an issue to develop. Have you ever TRIED to take one apart? with screws out it takes a hammer or link separator. Not that I'd want the screws out but little risk if the screws are essentially in.

With the nature of the taper of the tenon and hole 'tight' will depend on temperature.

If something less than one turn, don't worry about it. They're not going anywhere.

You should ensure they are the right screws but I'm not even going to try to explain that here.

Medium loctite would probably be okay but why do something the MANUFACTURER doesn't recommend? Pulling the reserve off for maintenance or repair should not require extra effort.

This is a problem only in your imagination. But good to ask.

BTW it being a 182 operation probably means they have MORE time to do maintenance and certainly doesn't imply the Rigger is any less diligent.Unimpressed Lose your prejudice.


baronn  (D 22387)

Aug 17, 2013, 10:47 PM
Post #3 of 10 (1862 views)
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Re: [councilman24] Locktite on reserve links [In reply to] Can't Post

Finger nail loose. I opened a rig up and in just stretching the lines out, discovered the left rear link was bent. How did that happen? Upon urtherinspection, it had a ride on it from 7 yrs before. No data cards on the rig (yeah, what was with that) however, I knew most of the riggers that had touched this. At least 2 repacks per year. It had less than 1 mm of the barrel in the whole. Extremely unlikely to have survived even a non terminal opening IMO. Finger tight screws. It scared me. The risk/reward here seems obvious. Why take a chance? Lock it down.


riggerrob  (D 14840)

Aug 18, 2013, 2:08 PM
Post #4 of 10 (1599 views)
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Re: [baronn] Locktite on reserve links [In reply to] Can't Post

L-bar links frequently loosen due to expansion and contraction during heating and cooling cycles.
Re-tightening them - at every inspection - is standArd procedure, but if you have to tighten them more than a quarter turn, the last rigger did not do his/her job properly.


councilman24  (D 8631)

Aug 19, 2013, 12:00 PM
Post #5 of 10 (1292 views)
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Re: [baronn] Locktite on reserve links [In reply to] Can't Post

baronn wrote:
Finger nail loose. I opened a rig up and in just stretching the lines out, discovered the left rear link was bent. How did that happen? Upon urtherinspection, it had a ride on it from 7 yrs before. No data cards on the rig (yeah, what was with that) however, I knew most of the riggers that had touched this. At least 2 repacks per year. It had less than 1 mm of the barrel in the whole. Extremely unlikely to have survived even a non terminal opening IMO. Finger tight screws. It scared me. The risk/reward here seems obvious. Why take a chance? Lock it down.

I don't understand your description. "Finger nail loose" wouldn't be a problem if screw essentially fully seated and l bars seated. "Bent" link? I can't for the life of me see how an L bar would bend. If assembled it should be more than strong enough. If not assembled I'd assume it would separate before bending. I guess at a rating of 3000lbs Ts (12,000 breaking) it could if loaded singly at terminal but in 33 years I've never heard of a bent L bar.

"It had less than 1 mm of the barrel in the whole. Extremely unlikely to have survived even a non terminal opening IMO. Finger tight screws. " This doesn't make sense. Not sure what your calling the barrel. If you mean the long end of the l bar in the round hole the screws couldn't be finger tight for it to be only 1 mm in the 'whole' (sic). Just to start the screws there is about 2mm of what I call the tenon in the hole.

If the screws were about to fall out lock tite wouldn't have helped. This is a rigger error. They do not come loose like that in service. As above they may loosen a 1/4 turn or a little more but any more was packed that way.

Since it was bent I assume you replaced. Can you post a photo?

To you original question, if assembled corrected they do often loosen slightly but doesn't compromise the strength. Loc tite not needed. If screws nearly fully out a rigging error (screws should be checked every pack job) and loc tite wouldn't help. They just don't back out that far in use.


hackish  (No License)

Aug 19, 2013, 8:06 PM
Post #6 of 10 (1127 views)
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Re: [baronn] Locktite on reserve links [In reply to] Can't Post

Keep in mind UPT sees, assembles and repacks more rigs than any one rigger will ever work on. When they say they don't recommend it to me it means don't do it because when properly assembled it's not a problem. Personally I've always checked the l-bars on 15-20 odd rigs and have never found a single one that had a loose screw.

-Michael


baronn  (D 22387)

Aug 20, 2013, 10:08 AM
Post #7 of 10 (1018 views)
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Re: [councilman24] Locktite on reserve links [In reply to] Can't Post

This is the thing that just gets me more than anything in this Sport/Business. 1st thing when I post these is I get questioned on the validity of the post. Or I get schooled in what is obvious. I don't do this for that reason. It's to show what I am finding and hopefully avoid anyone else from causing the same mistakes I have found. The link that is bent was on a rig I was jumping at this place. Thank God I didn't have a reserve ride on it. Scared me but good. If my post can help avoid this, that's what it's about. Save yer lessons for someone else and take the info for what it's worth. And by the way, 1 of the riggers that missed this was a DPRE.


mark  (D 6108)

Aug 20, 2013, 1:15 PM
Post #8 of 10 (950 views)
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Re: [baronn] Locktite on reserve links [In reply to] Can't Post

baronn wrote:
The link that is bent . . .

I'll echo Terry -- any chance of a photo of the bent L-bar? Also, could you speculate on how the L-bar was loaded to make it bend?

Mark


piisfish

Aug 20, 2013, 1:38 PM
Post #9 of 10 (914 views)
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Re: [baronn] Locktite on reserve links [In reply to] Can't Post

I generally use a very flashy nail polish, just a small line across so I have a tell-tale plus the polish is often enough just to stop screws unscrewing


pchapman  (D 1014)

Aug 21, 2013, 5:48 PM
Post #10 of 10 (705 views)
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Re: [baronn] Locktite on reserve links [In reply to] Can't Post

baronn wrote:
The link that is bent

To clarify:
You keep making it sound like you found a bent L-bar. That's why you are being questioned.

Do you instead mean that you found a bent Maillon rapide link, which had the barrel unscrewed? That's what I thought you meant.



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