Richard,
No one has gotten back to you on this so I thought I would chime in.
The measurement that you provided is on the low end of a 1 1/8 hex (the
min listed is 1.088 across flats). You should be OK with a 1 1/8
socket. The torque should be based on fastener strength. I made the
chart on the C&C site from info that I found a long, long time ago. We
had a discussion a while back on the torque levels in the chart and
whether they should be applied to dry or lubricated threads. After
looking at it again, the tables 250 ft-lb is pretty aggressive (assuming
18-8 stainless) and I might back it down to 150 ft-lb dry or 100 ft-lb
lubricated. Those torques will bring the fastener to about 37,000 psi
with a tensile yield allowable of 42,000 (minimum value that I could
find, Stainless yield is not always listed). These torques will give
you a little less than 12,000 lb theoretical clamping force. We used to
say the proper torque was tighten till it stretches.
Hope that helps, but in all likelihood it will probably create a bigger
discussion. In the missile business we called stainless steel fasteners
"butter bolts" because of the yield strength, but that is what our keel
bolts are and that is what we try to live with.
Neil Schiller
BSME Michigan Technological University, 1977
1983 C&C 35-3, #028
"Grace"
Whitehall, Michigan
WLYC
"Yes, I was a rocket scientist!"
On 6/26/2018 3:13 PM, bushmark4--- via CnC-List wrote:
Help! I am working on the torque for my keel bolts; (1985 37 CB); I am
having difficulty in two areas; No 1. finding a deep well socket for
tightening the keel bolts; my problem seems to be the size of the
bolt; (or more likely, my poor measuring); I measure the bolts at 1
3/32; no one carries a socket for that size; it seems to translate to
between 27 and 28 metric, and the least expensive deep well sockets I
can find are about $30-50 bucks apiece; can anyone point me in the
right direction? Am I measuring wrong? or is there a standard size I
should go with...
No. 2; do the torque measurement numbers on the Photo album apply to
centerboard keels and as well as fixed keels?
any help is appreciated...many thanks
Richard
s/v Bushmark4; 1985 C&C 37 CB; Ohio River, Mile 596:
Richard N. Bush
2950 Breckenridge Lane, Suite Nine
Louisville, Kentucky 40220-1462
502-584-7255
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_______________________________________________
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
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