Hi Josh, I tried a number of sources to try to find torque values for the largest bolts, including exchanging a few emails with Mars Keel to no avail. Then I just did some internet research to come up with a torque value I could live with, keeping in mind there was some fibreglass laminate that is sandwiched between the keel and keel nuts and not wanting to crush that material. So my two values for the two largest bolts do "consevatively correlate with the wet/lubricated specs from a general online chart."
The other values I used came from the C&C Website. I'll say the value for the 1/2" bolt feels too high when you actually do the torquing so I may have used a somewhat lower value for that one. Ken H. On 2 January 2018 at 22:16, Josh Muckley via CnC-List <cnc-list@cnc-list.com > wrote: > Ok so now I'm confused and concerned. Neil Schiller got me thinking about > the science and standardization of the torque specs. Wet, dry, tension, > yield strength... So I did some investigating. I expected that the specs > on the c&c photo album would loosely correlate to those in a standard > engineering document. Boy was I wrong! > > I don't know where the torque specs on the c&c photo album came from. It > looks like the values for my largest 2 bolts consevatively correlate with > the wet/lubricated specs from a general online chart. The rest of the > smaller bolts are progressively less conservative. In fact the rating on > the photo album page is almost twice that of the online chart! Wet or dry, > 80 vs 45 - Quite concerning. > > Thoughts? > > http://www.cncphotoalbum.com/doityourself/torquebolts/torquebolts.htm > > https://www.fastenal.com/content/feds/pdf/Torque%20of%20Stai > nless%20Steel,%20Non%20ferrous%20Torque.pdf > > Josh > > > > On Jan 2, 2018 3:18 PM, "Josh Muckley via CnC-List" <cnc-list@cnc-list.com> > wrote: > >> Ok Guys, >> Since I have the mast out, this provides the rare opportunity to access >> ALL of the keel bolts. I've measured each of the bolt and nut diameters >> and checked the archives for torque specs. I intend to buy a toque >> multiplier and the appropriate sized sockets. I think I can do it for less >> than the yard is going to charge and I'll come out of it with some tools. >> I'll also be able to tell myself that it was done correctly. >> >> That being said it sounds like the best practices are are follows: >> - be on the hard >> - loosen the bolts one at a time, clean, and lubricate with tef-gel >> - reinstall and torque at progressively higher levels. >> >> I was unable to find the torque spec for my 1.5" bolt in the website but >> Ken Heaton cited 600lbs in one of his past responses. >> >> Keel bolts (fwd to aft): >> Nut stud torque >> 1 - 1 1/2 (38mm) 1 (25mm) 350 >> 2 - 2 3/16 (56mm) 1 1/2 (38mm) 600? >> 3 - 2 3/16 (56mm) 1 1/2 (38mm) 600? >> 4 - 2 3/16 (56mm) 1 1/2 (38mm) 600? >> 5 - 1 7/8 (47.5mm)1 1/4 (32mm) 450 >> 6 - 2 3/16 (56mm) 1 1/2 (38mm) 600? >> 7 - 1 1/2 (38mm) 1 (25mm) 350 >> 8 - 3/4 (19.5mm) 1/2 (13mm) 80 >> >> >> *Anything I'm missing?* >> >> >> Thanks, >> >> Josh Muckley >> S/V Sea Hawk >> 1989 C&C 37+ >> Solomons, MD >> >> _______________________________________________ >> >> Thanks everyone for supporting this list with your contributions. Each >> and every one is greatly appreciated. If you want to support the list - >> use PayPal to send contribution -- https://www.paypal.me/stumurray >> >> >> > _______________________________________________ > > Thanks everyone for supporting this list with your contributions. Each > and every one is greatly appreciated. If you want to support the list - > use PayPal to send contribution -- https://www.paypal.me/stumurray > > >
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