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| S&S Swan General - Threads on the toggle turnbuckle |
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Join Date: 16 February 2007
Posts: 199 |
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Threads on the toggle turnbuckle Dear Friends, Mon cher Lars, A small inquiry: I ma presently going through the whole rig and doing as much as possible. I discovered that toggle turnbuckle holding the top rod stay shows strange signs of fatigue: the threads, in a limited area, are “flattened”! This toggle is massive, it receive a long pin (about 360mm lång) of an inch or almost (25,27 mm. to be exact, or 0.995 in.) The threads on the pin are ok, but are not in the toggle itself. My questions are: 1- Would it be possible to “re-format” the threads in the toggle without losing too much material? If yes how? 2- If not, would a replacement of the toggle be enough, or should I replace even the pin, since the two have been together for many years? 3- In the attached pic you will see that the pin is quite “red”. It is in Bronze, I supposed, however, it should have some sort of coating making it look like stainless steel. Is that right? If yes, what might have had happened with the coating of the pin? Thanks a lot in advance for any suggestions. Cheers//Philippe//47/050 Farouche  |
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Join Date: 02 January 2008
Posts: 1547 |
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Mon cher Philippe Answers 1. If the screw turns easily when screwed into the damaged thread area the conclusion is that the top of the threads have been stripped away locally, and this portion of the thread is not reliable any more. Provided there is at least 1 inch of undamaged female thread length left where the screw can engage properly it would appear possible to continue to use the parts, but physical strength testing is strongly recommended before taking this decision. Generally, damaged threads can be restored by drilling out the old threads and putting in Heli-Coil inserts, but this can not be recommended here because so much material is removed by this process that the strength of the threaded area is reduced 2. The screw needs to be examined carefully before taking the decision to continue using it. The threads to be cleaned thoroughly with solvent to remove all lubricants, finally use a stiff brush to get the thread bottoms properly cleaned. The problem to look for is cracking at the bottom of the threads. It would not hurt to check all the turnbuckles in the same way. In view of the age of the parts the recommendation would be to replace them if there is any doubt. 3. The screw is bronze, and has originally been nickel plated, apparently this layer has worn away. The purpose of the nickel plating is to enhance the appearance, and reduce the risk of thread galling as it provides additional lubricity. For some reason there has been galling in the stainless threads although bronze in itself has good lubricity properties. Bien amicalement Lars |
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Join Date: 16 February 2007
Posts: 199 |
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Mon cher Lars,
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Join Date: 30 January 2007
Posts: 462 |
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Philippe, |
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Join Date: 16 February 2007
Posts: 199 |
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Hello Daniele, Thanks for the information. As a matter of fact I did find all the specifications - after receiving your message - which where given to me by Nautor some ten years ago. The S&S spec. says: " Main Shrouds - Two Navtec size 40 with toggles at deck". It does not say more than that. Looking at the present part list from Navtec, there is indeed one "size 40", where 40 is the size of the Rod. Starting from there, we had to work out the type of threads, the size of the pin (0.995 in!) etc. I will be getting the parts the next week. I am crossing my fingers and I will report the result with the parts number for anyone else who might need those in the future. Cheers Philippe (47/050 Farouche) |
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