Ronstan calibrated turnbuckles

[Wet Spreaders]

We use shroud adjustments all the time to tune for wind speed. One of the shroud tensioning turnbuckles became really stiff and I assumed that the thread had some crap in it. After unscrewing it (hot!) I found that the problem was the captive spinning nut thing on the top. Semi-seized and really hard to turn, even unloaded.

I removed the unit from my boat and tool it home. A few hours soaking in PB-Blaster and some wiggling freed it up and now it spins normally. What do you all think? Is the nut still properly captive or am I risking having the nut pull off the turnbuckle body, taking down my rig? What does the interior cross section look like?

 

[slug zitski]

We use shroud adjustments all the time to tune for wind speed. One of the shroud tensioning turnbuckles became really stiff and I assumed that the thread had some crap in it. After unscrewing it (hot!) I found that the problem was the captive spinning nut thing on the top. Semi-seized and really hard to turn, even unloaded.

I removed the unit from my boat and tool it home. A few hours soaking in PB-Blaster and some wiggling freed it up and now it spins normally. What do you all think? Is the nut still properly captive or am I risking having the nut pull off the turnbuckle body, taking down my rig? What does the interior cross section look like?

Galling is an issue with stainless to stainless contact 

you must use assembly paste on all stainless threads 

tefgel , copper paste .....several to choose from 

 

[Wet Spreaders]

Galling is an issue with stainless to stainless contact 

you must use assembly paste on all stainless threads 

tefgel , copper paste .....several to choose from 

Yeah, maybe galling internally. The turnbuckle body is definitely stainless, but I'm not sure that the captive nut is - I wonder if it's bronze. It's pretty chewed up and scratched, whereas the body is pristine. 

 

[slug zitski]

Yeah, maybe galling internally. The turnbuckle body is definitely stainless, but I'm not sure that the captive nut is - I wonder if it's bronze. It's pretty chewed up and scratched, whereas the body is pristine. 

To address galling Stainless ...bronze , is a common combination for rigging screws 

many are stainless ..stainless 

regardless is composition   , always use assembly paste

 

[waXrules]

The coupling nut inside the turnbuckle is nickel plated bronze.  Having said that, we still lubricate when putting the mast up every year using Boeshield T-9 spray.

 

[Wet Spreaders]

The coupling nut inside the turnbuckle is nickel plated bronze.  Having said that, we still lubricate when putting the mast up every year using Boeshield T-9 spray.

I think this was operator error by me. I assumed that the little hole in the side of the bronze nut was lubricating the bearing between the turnbuckle body and the nut, but after investigating it looks like it lubes the threads of the stainless swaged on shroud end. It's not clear whether the lube makes it into the bearing surface or not. I guess not based on the resistance of the setup before I freed it up.

 

[Steam Flyer]

You can see how bad the galling is with a strong magnifying glass. Worht knowing about.

There may also be some axial play with the nut, you can measure it with a dial indicator.

If the threads are only bunged up in the area that the lock nut engages, not the turnbuckle bottle itself, then you're probably fine. But turnbuckles with galled threads are a risk, under load.

FB- Doug

 

[Wet Spreaders]

You can see how bad the galling is with a strong magnifying glass. Worht knowing about.

There may also be some axial play with the nut, you can measure it with a dial indicator.

If the threads are only bunged up in the area that the lock nut engages, not the turnbuckle bottle itself, then you're probably fine. But turnbuckles with galled threads are a risk, under load.

FB- Doug

The problem is not the threads of either the shroud or the nut. It's the bearing between the captive nut attached to the turnbuckle body, and the turnbuckle body. There's some kind of hidden rotating joint that allows the bronze nut to turn, while remaining fixed to the stainless turnbuckle body. That joint became incredibly stiff. I have freed it off using patience and PB blaster over a couple of days (no heat), but I'm concerned about the internal construction. Ronstan don't publish a cross section so there's no way to know how much meat is present preventing the nut from coming loose from the turnbuckle body. 

 

[ctutmark]

The problem is not the threads of either the shroud or the nut. It's the bearing between the captive nut attached to the turnbuckle body, and the turnbuckle body. There's some kind of hidden rotating joint that allows the bronze nut to turn, while remaining fixed to the stainless turnbuckle body. That joint became incredibly stiff. I have freed it off using patience and PB blaster over a couple of days (no heat), but I'm concerned about the internal construction. Ronstan don't publish a cross section so there's no way to know how much meat is present preventing the nut from coming loose from the turnbuckle body. 

A couple/few years ago Ronstan changed the design of their turnbuckle bodies, both calibrated and non-calibrated. The overall length appears to be the same so new can easily swapped for old. Maybe it's time to upgrade. 

Here's a pic of the new style 

 

[patrese]

If it was hot while unwinding, better dump it!

Had the same thing on my Melges24 sized rigg with similiar turnbuckles from Bluewave (DK)...

The topshrout turnbuckle "exploded" while setting up rigg-tension one day -luckily still on the hard...

Would have cost me the rigg and sails 24h later....

Bluewave swapped all 4 turnbuckles (from the same series) for a very good price and had a happy costomer for the next years!