On Wed, 14 Jan 2009 18:44:54 -0600, cavelamb
wrote:

wrote:
On Wed, 14 Jan 2009 21:13:59 +0100,
wrote:

Hi,
can anyone advise me on the roughly correct torque setting for
tightening the nuts on my keelbolts?
The studs are 20mm (thats about 13/16") in 316L plus one at
12mm(about 1/2")

The keel is 2 tonnes of lead if that makes any difference.

I'd hate at this stage (five long and bloody years) to over or
undertighten the bolts.

Thanks
Pete

1/2 inch = 80 pounds
3/4 inch = 250 pounds
1 inch = 350 pounds

These figures above are for DRY hardware. Being stainless, it's highly
advisable to apply some lanacote or grease to avoid galling.
Lubrication means reduce the torque figures above by 10%



Is that inch pounds or foot pounds???


From Engineer's Handbook
http://www.engineershandbook.com/Tables/torque3.htm

I get the following values for 316 Stainless (assumed course thread)

20 mm = 13/16"
3/4"-10TPI = 1582 "lbs
7/8"-9TPI - 2430 "lbs
interpolating
13/16" would be approximately 2006"lbs = 167 'lbs

12 mm = 1/2"
1/2"-13TPI = 542"lbs = 45'lbs

From experience: Most common stainless alloys aren't very strong and
tightening to levels recommended for some steel bolts will frequently
result in stretched bolts.

for metric steel bolts:
12mm 5D (71,160 psi med. carbon steel) = 34'lbs
8G (113,800 psi med. carbon steel) = 54'lbs
12K (170,674 psi Med. Carbon) = 86'lbs
22mm as above 182, 284, 464 ft. lbs.
Cheers,

Bruce
(bruceinbangkokatgmaildotcom)