Hand drilling an emergency anchor
If you’re climbing a little-traveled big wall, or venturing into soft-rock climbing areas like Utah’s San Rafael Reef (see story on page 34), you may want to carry an emergency bolt kit—and know how to use it. Here’s the lowdown.
Sometimes, in very soft rock, no mechanical bolt will tighten properly. Then, just as in the early days of desert climbing, angle pitons driven deeply into drilled holes become your weapon. “Drilled angle” anchors are directional; just like a nut, they have little direct pullout strength. This makes them dangerous when treated like conventional bolts, and because of this they have fallen out of favor. Nevertheless, a few angle pitons up to 3/4-inch, carried in addition to your standard bolts, can save the day in super-soft sandstone.
The bits in an emergency drill kit should be brand new and sharp. I carry a drill that accepts SDS bits, for ease of bit change-out; other systems use easy-to-lose set screws or jam-prone tapered shanks, and the bits are harder to find. Regardless of shank style, look for a rock bit with a pair of carbide “wings” at the tip, with the fluted portion of the bit slightly thinner, so the bit doesn’t bind—a serious problem when drilling in hard rock. The downside of a “wing-tip” bit is that it wobbles more easily, risking sloppy holes.
Choose the best stone. Doublecheck that you’ve chosen solid, monolithic rock by tapping with your hammer. Listen for dull or hollow sounds that betray spongy or honeycombed rock, or invisible plates. Don’t drill into a block or flake, and stay at least 8 inches away from fractures or sharp arêtes.
Drilling the hole. A hand drill is a rotating chisel. The threads do not cut; rather, the drill’s tip chips away at the bottom of the hole. So don’t waste a lot of effort twisting the bit. Instead, turn the chisel point just a few degrees after each strike. Strike firmly: more than a tap, but not as hard as if driving a framing nail. Use your blow tube to clean the hole periodically; then you can also rest your arm and check your progress.
A good bolt hole is perpendicular to the rock surface and has a uniform diameter from bottom to top. Take special care drilling the first inch. Don’t change the bit’s angle or let it wobble; this will flare the hole and may prevent the bolt from tightening properly when you place it.
Finish strong. Holding the drill straight feels easier as you go deeper, but don’t get lazy and rest the bit against the edge of the hole—you’ll ruin your good work. Drill the hole at least 1/4-inch deeper than the length of the bolt, then blow out the dust, brush the hole with a test-tube brush, and blow again. Grit on the walls of the hole is a common reason bolts don’t tighten.
If you’re new to this process, allow at least half an hour to drill a 3/8- by 2 1/2- inch bolt in Yosemite granite, or a 1/2- by 4-inch bolt in desert sandstone.
Placing the bolt. With a hanger prefitted on the bolt shaft, set the bolt in the hole. For normal sleeve and wedge-type expansion bolts, this should require firm tapping with the hammer. If it doesn’t, or you can pull the bolt back out with your fingers, the hole is too big and the bolt will not tighten properly. Re-drill the hole at a larger diameter if you’re carrying bigger bolts—or start over. If you have to start over, you can pound small rocks into your botched hole to partially conceal your sorry failure (or, better, patch it properly with epoxy and grit).
When the hanger is flush against the rock, tighten the bolt’s hex head until it feels very snug with a small wrench—typically three to four full turns. The bolt just needs to bite firmly; overtightening will not make it stronger. If the bolt starts to tighten but then begins to spin, you can sometimes increase the bite by clipping a sling to the hanger and pulling out as you tighten. If the bolt still spins in its hole as you turn the wrench, the placement is botched. Remove the hanger and pull or bury the stud. Never leave a botched “death” bolt that looks OK.
- (4) 3/8 x 2 1/2-inch stainless wedge bolts
- (1) 3/8 x 3 1/2-inch stainless wedge bolt
- (1) 1/2 x 2 1/2-inch stainless sleeve bolt
- (4) stainless hangers
For desert sandstone and other soft rock:
- (2) 3/8 x 3 1/2-inch stainless sleeve bolts
- (2) 1/2 x 4-inch stainless sleeve bolts
- (1) 1/2-inch angle piton
- (1) 5/8-inch angle piton
- (1) 3/4-inch angle piton
- (4) stainless hangers
For more information on everything about bolting, check the American Safe Climbing Association website: safeclimbing.org.