Safety first : How to Identify Bad Climbing Bolts
Identify, plan for, and mitigate the hazards caused by sketchy bolts. When we encounter a bolt, we have no idea whether it’s good, bad, or just ugly. The reality is, bolts can fail due to metal fatigue, oxidation, improper placement. Or hidden internal processes like stress corrosion cracking (SCC), in which tiny fissures form in the metal due to chemical reactions.
While the design and construction of modern bolts make this a rarity on, say, routes from the past decade, older bolts with smaller diameters can fail. Identifying these bolts can help you assess the risk in clipping and making that next move. Some old bolts looked great. While others can brook with a flick of the rope. Knowing the difference can save your life.
A bolt can be bad either because the rock is bad or the bolt is bad. Or if it really isn’t your day, both are bad. To a large degree, the compressive strength—the force that the rock can withstand before breaking—varies by rock type. Granite tends to be the strongest, holding between 4,000 and 40,000 pounds. Good sandstone ranges from 1,000 to 20,000 pounds. And limestone typically holds between 1,000 and 5,000 pounds.
In general, be cautious when the rock around the hole has broken away. Or exposing the bolt. If the stone is fractured, there are spider-web cracks leading from the bolt hole, or if the surrounding rock is hollow (tap it with a knuckle or carabiner to see if it reverberates), the strength can be compromised.
At times, the nut or head of the bolt that holds the hanger to the rock can be loose, causing a “spinner.” In this case, finger-tighten the nut or bolt, which will make the bolt adequate for the moment. Carrying a small, adjustable wrench helps in these circumstance. Only tighten until it becomes significantly more difficult to turn the wrench past a logical “yield point,” lest the metal fatigue or snap.
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