To drill a hole in rock is never that easy, but it’s also never that hard and simply requires the tools, the time and the patience.
Before you start drilling make sure you have the right hardware. You should only use stainless steel bolts, ideally from recognised climbing companies such as Fixe, Petzl, Powers, Kong, Raumer, not cheap plated Chinese bolts off eBay. These bolts should also have all parts matched, so all stainless steel, from hanger, nut, bolt to washers, as mixing and matching, say a plain steel washer, alloy hanger, coated nut and stainless bolt will lead to a corrosive mix. Remember that you’re creating a work of art here. Don’t be cheap.
The basic principle is; hit the drill bit, turn the drill bit, hit the drill bit, turn… etc. When you hit the bit you’re making a hole, when you turn it you’re removing the debris from the hole and resetting the bit’s cutting edge, taking the bit out now and again to blow the hole clean and see how far - or not far - you’ve gone. The real art comes from digging a bit more into detail, such as how hard do you hit, how often do you turn, when do you blow the hole clear?
Pick Your Bolt And Your Bit
Make sure you have your bit and bolt matched as to put a bolt into a hole that’s too big is highly dangerous, while a hole that’s too small is a big waste of time! Try and keep your bits and bolts clearly marked so that someone who ends up drilling a bolt knows you can’t put a 10 mm bolt in an 8 mm hole!
Pick Your Spot
Make sure the rock is clean and solid and at least 30 cm from any cracks or other bolts. Make sure the rock is flat and not in a depression as this may interfere with the bolt hanger or even interfere with the belay, and you can check this by placing your bolt hanger on the rock before you start drilling.
Place the drill bit at 90 degrees to the rock and give it some hard strikes to create an indent to start. It’s vital that you begin very carefully and make the first 5 mm clean and create a sharp starting hole. Once you feel you’ve set the starting hole you can speed up.
The art of drilling the hole is to understand that you are not drilling away like a power drill does, or smashing the rock, but instead chipping the hole, each strike of the hammer breaking a few grains of rock away, like you’re a sculptor, each twist positioning the focus of the drill somewhere else.
Look at the tip of an SDS bit. It’s pointed and chisel-shaped, each blow focusing down the driver to the bit and down to that tiny point, the tip of the spear. If you hit too hard you’d destroy your bit, your driver, your hammer and your hand, as you’re basically just hitting the wall with your hammer. Tap too lightly and the bit will not be able to break the grains of the rock apart and you’ll never drill any kind of hole.
Instead what you need are hammer blows that are up to the job of chipping the rock, and that are sustainable and rapid, the death of a thousand taps, not one bit breaking blow. When you start off you should be able to judge the right kind of hammer blow you need by looking at how the surface of the rock reacts to the bit.
How Many Taps?
The number of taps before the drill is rotated is important as what you want is for the bit to chip away as much rock as possible but without binding, drilling a slot into which it sticks. You also need to factor in rhythm, as it’s the huge number of small taps that will get the hole drilled. I tend to vary between 5 medium taps then twist, and two hard taps and twist, it comes down to what suits your style, but as a guide, you want to be getting about 60 strikes a minute.
How Many Twists?
The twist is both changing the position of the bit so it has fresh rock to cut as well as allowing the bit to remove some of the rock dust inside the hole, which can cause the bit to bind and stick. When it comes to twisting, try and imagine the face of a clock. You insert your bit and imagine the long chisel running vertically from 12 o’clock to 6 o’ clock. Now twist the drill around the clock in hour intervals, so a twelfth of a turn at each turn.
How Often Do You Remove The Drill?
You tend to remove the drill to blow the hole clean or to check the depth to see if you can stop drilling and bang in your bolt. The natural movement will remove quite a lot of the rock debris, but blowing the hole clean every few minutes gives you a chance to rest your hands (have your blow tube close if you’ve got one). If you don’t have a blow tube then you can spit on the end of the bit and clean the hole out this way. As for depth, it’s a good trick to put an elastic band on your bit and position it for the depth you’re aiming to drill (or pre-mark it with tape), as this reduces the number of times you need to take the bit out and check the hole (one good thing with self-drives is that they have a mark on the driver which shows when you’ve hit the correct depth).
When hand drilling a stud bolt you will be tempted to drill the hole short and call it good - don’t!
A stud bolt requires a full-depth hole in order for the stud to expand the end cap, meaning that if you only drilled to the bolt’s first thread then tightening the bolt would not engage the stud at all, and you would only have an unsightly passive bolt, like a piton hammered in a hole. Having all the threaded parts sticking out makes clipping karabiners more awkward, can be a snag hazard for haul bags lifting from the belay, and a hazard on lead bolts, as falling into them or over them can cause nasty puncture wounds.
If you want to drill a shallow hole then make sure you drill to at least a depth that will take 50% of the bolt, but ideally the whole length of the bolt, minus the hanger, washer and nut. This means once tightened you will only have 3 mm of threaded end showing. In reality hand placed bolts tend to be placed in shallow holes.
The Drill As Pro
Sometimes you might be in a position where you are on a time bomb piece, and trying to drill a bolt, rivet or bat hook feeling the seconds counting down. If the piece you’re on fails, you’ll fall onto the drill handle, which is clipped into you somewhere, which will probably see the bit bend and break. If you’re desperate and just need to keep calm and keep drilling, then you can attach a #2 or #3 rivet hanger to the bit, and try and keep it as close to the rock as possible, clipping your daisy chain into it as short as you can. If you fall, and the drill is in the hole, you have a small chance of being held by the bit.
Placing An Expansion Bolt
Now you’ve got the hole, it’s time to place the bolt. The following is for the standard stud bolt:
With the hanger, washer and nut screwed onto the bolt, tighten the nut until it’s a few threads from the end, but not flush, as you don’t want to damage the nut or threads when you hammer the bolt into the hole, hitting the end instead.
Making sure the hole is clean, insert the bolt, pushing it in as far as you can by hand, which should not be far. If it slides in easily then you have a problem as you’ve perhaps used the wrong bit, or if in soft rock your drilling has created too large a hole.
Once pushed in, hammer the bolt home until the hanger touches the rock. The bolt should go in with some resistance but should not require major bolt bending force.
Make sure the hanger is orientated correctly, and begin to tighten the nut, turning it until you are unable to tighten any more (do not use the hammer to hammer on the spanner).
If the hanger is off centre then tap it back into place with your hammer. You’re ready to go!
Practise, Practise, Practise
The first time I had to place bolts on a route I was a third of the way up a new route on the Troll wall, solo and in winter. I was using bolts I’d never used and a system that was straight out of the bag. Mid pitch, hanging from a sky hook I tried to place an 8 mm button head bolt, whacking on the driver for all my might, thinking at the time that this was a game of violent penetration.
I’d only ever placed one bolt before, a self-drive in a small rock in a car park so was pretty much clueless, the articles I’d read giving me just enough knowledge to be dangerous to myself. When the hole was finally drilled I fished out the button head bolt and began to tap, the tip going in tight, millimetre by millimetre, until it got to the bolt’s thicker part, the part that would need to be compressed to lock it into the wall. At this point, it stopped moving, and so I hammered a little harder, but instead of going in it just bent over like a cheap penny nail. I tried to drill three more bolts on that wall, and all went the same way, a bent middle finger towards my lack of preparation and overconfidence, and in the end, they were my undoing, the dream and the wall undone by a simple lack of skill.
It is vital that all big wall climbers have a basic understanding of how to drill, how to rivet, how to place a bolt. This, of course, should not be done on any crag but on small rocks and boulders in your garden (a rock that won’t rock around and move when being drilled is ideal). A granite block is ideal for practice but any good-sized block is fine, and you should practice with different drill bits, hard and soft, fast and slow, to get an idea of how it works. If you’re climbing in a new location, such as on sandstone walls or strange alien granite, then consider just drilling a hole somewhere to test how fast and easy it is as this may affect your choice of line, as some rock can be hard like steel while others are soft as sand. Once you’ve place a bolt and rivet try taking them out again, another skill you may need.
Part 4: New routing.