loose nuts on bolts - how should they be tightened?

[ras]

Question for route setters, how tight should the nuts on bolts be? If I had a wrench, should they be finger-tight plus a quarter turn? Can you terminally weaken a bolt by overtightening?

Nuts are loose pretty often, and some recent experiences have made me think they should be tightened more than just with fingers, but I also don't want to damage them.

Found one on Bulldog at they Gym last weekend that had almost come completely off.

That wasn't a big deal, but a few weeks ago, while cleaning an anchor on a route down in Vantage, i guess I wiggled the rope enough to unscrew the second bolt on a route. It was the crux bolt, hadn't hadn't appeared loose when I clipped it, and I'd fallen on it on my first run, and sat on it on my second. Hm.

[Dru]

It depends on the type of bolt. Torque bolts used in many US climbing areas have a rated torque to apply and should not be overtightened; for the nuts on the wedge/cone bolts like commonly used around Squamish and sold at MEC, they can be reefed as tight as possible with a wrench. If just hand tightened, they often loosen over time.

[ras]

It depends on the type of bolt. Torque bolts used in many US climbing areas have a rated torque to apply and should not be overtightened; for the nuts on the wedge/cone bolts like commonly used around Squamish and sold at MEC, they can be reefed as tight as possible with a wrench. If just hand tightened, they often loosen over time.

The torque bolts are the ones without a nut, and the head of the bolt is usually about 4 mil thick?

Wish I had a picture.

[Dru]

http://www.safeclimbing.org/education/mechbolts.htm

[bike]

I also add a drop of lock tight which helps eliminate loosening. Medium strength.