RRC Archives

What size heads are the bolts in the red? I have a tendency to find loose bolts and instead of yelling at someone I want to tighten the problem and I don't want to lug a metric and English wrench set from Michigan just to figure it out.

use a 9/16" wrench

Rick was passing out wrenches to people as they went down into Muir Valley on a few different weekends. Surprisingly, he commented that they all returned saying that nothing needed tightening.

i've been meaning to get one to add to my sport rack

Sunshine has been there a few times and probably tightened everything already. LOL As he recommended, a 9/16 offset wrench with a hole on the other end so you can carry it using a 'biner.

Meadows, Sunshine did not tighten everything at Muir. I have been retighting bolts all over Muir the last few months. Believe it or not Sunshine is not the only person that knows anything about bolting routes or maintaining them.

t bone wrote:Meadows, Sunshine did not tighten everything at Muir. I have been retighting bolts all over Muir the last few months. Believe it or not Sunshine is not the only person that knows anything about bolting routes or maintaining them.

Ah, so true! The Muir Valley developers are certainly not incompetent.

I was able to get a fair deal on forged 10-inch long 9/16-inch box end wrenches. The other end is a 1/2-inch box, through which a piece of perlin can be tied. A strong climber can apply about 35 foot-pounds of torque with this wrench. Any responsible climber who climbs in Muir and wishes to have one need only see me at the Muir parking lot for a free wrench. I've already passed out about a couple dozen.

One point that should be made here is that a loose bolt does NOT necessarily mean that the developer of that particular route didn't torque it down adequately. This applies to ANY climb on ANY wall in the Red. This Corbin sandstone stuff that we bolt into is so soft that when a hanger is torqued under the load of a fall (or just hanging weight at the anchors), it can pulverize a thin layer of rock between the hanger and the wall as it pivots. The pulverized dust falls away and leaves a tiny gap between the hanger and the wall. Now the hanger can spin.

It should give some comfort to those of you encountering a loose hanger that, so long as the bolt head is in close to the hanger, a loose hanger will fail at about the same load as a tight hanger. Failure tests on hangers tightened with Dynabolt Golds to 50 foot-pounds of torque failed at the same general value (4000+ pounds) as did hangers that were first tightened, then loosened to ZERO torque (finger loose). To appreciate why this is true, envision a Chinese finger puzzle. The Dynabolt has an expansion cone that tightens inside a sleeve and secures the bolt to the rock, regardless of whether or not the hanger is loose or tight. The harder you pull, the tighter the grip on the rock.

Rick

Another point to ponder about spinners...

Several of us are interested in glue-in bolts and have been testing them. This is a very popular way of bolting in sandstone and other softer rock around the world.

But, one significant negative for a glue-in is the fact that, like the expansion bolt, the attached hanger bracket can be torqued loose under a large load. Now, what does one do with a spinner when the glue-in bolt cannot be re-tightened? Left spinning, over time the hanger bracket can wear away a stress riser on the bolt shank and weaken it.

We don't have an answer yet for this dilema.

At least expansion bolts can be re-tightened when they become loose.

Soon, I hope to test some hangers attached by Dynabolt Golds -- with and without a tough, weatherproof, penetrating urethane adhesive applied between the hanger and the rock. We will see if the urethane discourages the hanger bracket from being spun. The urethane also has the possibility of penetrating into and bonding with the sandstone directly next to the hanger, thereby giving it better structural integrity and resistance to pulverizing.

Rick

I just get the sense that you guys are having way too much fun! Carry on.