How to Use Bolts in Rock

A climbing bolt and hanger.

Using bolts for protection in rock climbing is somewhat controversial, given that they permanently scar the rock. If you're going to use bolts, you must place them correctly. Bolts used in climbing should be of no less than 3/8-inch diameter, with 1/2-inch diameter bolts preferred. Because they need to last a very long time, climbing bolts should be made of stainless steel. There are two kinds of bolts commonly used in rock climbing: expansion bolts and wedge anchors. Glue in bolts are also available and are especially useful in soft rock, however they require special training to install correctly.

Bolt holes should be drilled using a hand drill and hammer, or a portable electric hammer drill. In either case installation of the bolts is the same.

Different climbing areas have differing traditions concerning bolting, and some areas on public land have outright bans. Ask around before you bolt a route.

Things You'll Need

• Safety glasses or goggles
• Cordless hammer drill, or hand drill
• Drill bit
• Hammer
• Plastic tubing
• Stainless steel bolts
• Stainless steel bolt hangers
• Wrench

Instructions

1. Attach the bolt hangers to the bolts. Loosely screw the bolt hangers onto the bolts while you're still on the ground.

2. Locate the best spot for the bolt. Tap the rock with your hammer to assess its quality. Be certain the bolt is at a stance where the climber can let go with one hand to clip it. If you're bolting a sport climb on rappel, top rope the climb and mark your bolt locations with chalk or a felt tipped marker.

3. Using the drill, make a hole 1/4-inch to 1/2-inch deeper than the bolt length. If using a hand drill, tap the drill, give it a turn, and repeat. Hit the drill hard, but not so hard that the tip bounces off the rock. Using a sharp bit in a hand drill, a 3/8-inch, 3 1/2-inch deep hole takes 30 to 45 minutes to drill in granite.

4. Insert the plastic tubing into the hole, and blow out the rock dust.

5. Insert the bolt into the hole. It may take a few light taps with the hammer to get the bolt all the way into the hole.

6. Tighten the bolt finger tight, then two to four turns with the wrench. Over-tightening or under-tightening will weaken the bolt installation. Always follow the bolt manufacturer's torque recommendations.

Tips & Warnings

• Your life and the lives of others depend on properly selecting and placing bolts. Get professional instruction before placing bolts.

• Practice drilling and setting bolts on the ground. Find a piece of concrete or stone and practice placing bolts at home.

• Climbing is dangerous; climb at your own risk.

• Wear safety glasses or goggles when drilling.

• Hardware store bolts are of variable and often dubious quality. Use bolts designed specifically for climbing. Never make your own bolt hangers.

References

• Safe Climbing: safe climbing information
• Big walls: drills, hangers and bolts

Resources

• American Safe Climbing Association