Bolt Hole Cleaning

One crucial step of sport bolting is thorough cleaning of the hole before placing the bolt. This is particularly important when using glue-in bolts but is often overlooked as a step in placement of cone style, 5p rawl and fixe bolts. Dust and loose rock particles left over from the drilling process can only weaken the bolt placement. Removal of only the loosest [dust] particles by forcing air down the hole results only in a partially cleaned hole.

An effective method of cleaning a bolt hole requires a brush slightly larger than the hole to be inserted and removed with a spinning motion। Several repetitions of this while blowing the hole out in between will clean a very large majority of loose material from the hole.

Glue-in bolt considerations:
When cleaning holes for glue-in type bolts, it is best to use a bulb - type blower or canned air. Lung - generated air will introduce moisture to the hole, decreasing the amount of fine dust that is cleaned from the hole and also leaving behind moisture which can reduce the bonding power of the resin. Also , when using a wire brush, do so in moderation. Excessive cleaning with a wire brush can smooth over very small irregularities caused by the drilling process that are crucial for the glue to perform at its peak abilities. If possible, test your brush on a small piece of stone from the area you're bolting and of the same stone. Softer stone (such as sandstone) won't hold up near as well to wire brushes; in this case, nylon or other plastic may be a better choice.
Finding a brush to clean bolt holes may be a chore so I have provided the following how-to for a homemade cleaning brush. Total material cost is under $5 and labor involved is roughly an hour. Requires access to a torch, power drill with 5/32" bit and welder. Materials list is:

7" 1/4 cold roll steel ($3.00)
1 4.10 shotgun bore cleaning brush (Wal-mart; $1.98)*
A couple feet of some leash line of your preference.
*Note: the 4.10 shotgun size is perfect for 3/8" holes. Some measuring will have to be done at the gun section of wally world to figure out the optimum size for a 1/2" hole. I will update and post back here when i get around to figuring this out.

Use a center punch to mark the center point of one end of the 1/4" steel rod. Drill out about a 1/2" depth into the end of the rod being careful to go in as straight as possible. Access to a drill press would be very beneficial for this step. I eyeballed mine with good results. Cut off the rod at the desired length to make a t-handle. I made mine capable of a 5" depth with the brush attached.

Cut and weld the t-handle onto the top of the main body. If you are feeling creative, leave enough to form a loop on one end of the handle as in my example for the leash line. Otherwise, a leash can simply be attached to the main shaft. Remove the threaded knob from the brush and insert it into the end of your brush holder. Several taps will ensure a good seat. I actually tapped mine in with a hammer to the point of the coils of the brush buckling up slightly.

You should have something to this effect (click on image for larger view).


Several variations of this basic design may be accomplished with some creative thinking। This design is particularly useful because the brush tips may be easily changed out 'in the field'. To change the tips, simply grab the exposed portion of brush with a set of needle nosed vise grips and pull with a twisting motion. Keeping a supply of brushes on hand won't break the bank either at $2 each.

Hand Drill Efficiency

NOTICE: The purpose of this review is to provide insight into the abilities and efficiency of hand drills. This review is, in no way, intended to provide instruction on how to bolt stone for outdoor rock climbing. Sport bolting of outdoor climbing routes should only be done by a trained professional.

Sport bolting has enough ethical dogma surrounding it without me generating fuel for argument so my goal here is to stick to the facts. I know i will stray somewhat, but the point of this article is to give some insight into the practical efficiency of hand drills. The intent is to provide some empirical insight into what lengths of time should be anticipated for sport bolting with a hand drill vice a power drill.

It is imperative that you drill with a bit the size of the bolt you intend to use. Several schools of thought are around on the Internet stating that it is acceptable, for example, to use a 12mm drill to make a hole for a 1/2" bolt. As there is (at the time of this article) no empirical evidence to substantiate these claims, no one should be making these judgement calls on their own. Bolts left behind by your efforts will someday be employed for use by others with similar aspirations and their safety lies in the fruits of your judgement calls. Responsible bolting is among the last lines of defense of climbers aiming to maintain access to what climbing areas are left open to the public. This means (however, not limited to) camoflaged bolts, bolts only were neccessary, bolting when other climbers aren't present en masse, and bolting correctly. Weak bolts are worse than no bolt at all!!

A Petzl Rocpec is used in this article however there are many other models and styles to choose from. The Petzl Rocpec may be purchased for around $60 at most rock climbing outfitters such as GearExpress. The Rocpec is specifically designed to take the SDS style masonry bit in sizes of 3/8" to 1/2" standard and 10mm to 12mm metric. Drill bits (aka: "drills") may be purchased for between $9 and $18 online but i find that Lowes hardware has the best deal going at $7 for a 3/8".

The sample rock here is about a hundred pound specimen of either limestone or possibly dolostone giving it a Moh's hardness of about 3-4. This is about or slightly over than the mean hardness for most US climbing areas. The hole being drilled is to 2 1/2" depth at 3/8" diameter.

The hole is drilled in 60 second intervals to provide photos of the bit head and hole at each minute through the process and to best simulate breaks and overall project lapsed time. A 16oz ball pean hammer is used with a strike frequency of about 90 6" swings per minute. Very light to medium strikes are used to minimize distortion of the hole and damage to the drill.

A word on technique: Holding the drill and drill holder 90 degrees to the plane of the rock face is the single most important factor in the process. Attention must be focused on drilling a hole with sides not only as straight as possible but also perpendicular to the rock face.

Okay so on with the show:

After minute #1 :

Very light wear being shown on the tip of the drill. About 1/4" inch of hole already.








After minute #2:

Drill point rounds over slightly. Hole depth at about 3/8".









After minute #3:

No noticeable change in drill condition. Hole depth at approx 1/2".








After minute #4:

Not that the picture reflects it but expected rounding of drill tip and edges slightly worn. Hole depth approaching 3/4".







After minute #5:

Drill shows expected wear - still very light. Hole just over 3/4"; almost 7/8"








After minute #6:

Hole at 1 1/8" depth.










After minute #7:

Hole at 1 3/8".










After minute #8:


Hole at 1 3/4".









After minute #9:

Hole jumps to just under 2 1/2" in a minute of drilling. My only conclusion here is that a soft pocket in the rock was reached.








So total drilling time in this example amounts to nine minutes. Now, personally, i don't have the forearm stamina to maintain a 90 strike per minute hammering rhythm for a continuous nine minutes. Between blowing the hole out and photographing the progress, i would say the breaks were about 3 minutes long. Rounding this up to 30 and adding the actual drilling time brings us to roughly 40 minutes per hole.

The mean depth per minute of drilling comes out to just under 5/16" (possibly 9/32") or between 7.5 and 8.0mm. I haven't crunched the figures this far but standard deviation on this example would be rather high due to the large jump on the last minute.

In closing consider the following: My swings were against the drill holder set against a horizontal surface meaning that my strikes were in the most comfortable and ergonomically beneficial configuration possible. I plan to do an exact replica of this experiment against a vertical rock for comparison but i would venture to say that adding an additional 4-5 seconds per degree of vertical rise from a horizontal plane should be anticipated.

The Dropa Effect

I've always found theories of archaeological findings interesting. I put this together from various sources of information about stones found in China almost 70 years ago.

It's 1938 in the remote mountain range of Baian-Kara-Ula. A Chinese archaeologist, Chi Pu Tei, uncovers several mummified human-like remains in a cave. They are between four and five feet tall, with enlarged heads and arranged in a well-organized burian room. Adjacent rooms within the cave are recorded as being carved from the surrounding stone in a precise cubed manner. Later testing reveals the remains and surrounding artifacts to be over 10,000 years old. In comparison, the Great Pyramids of Egypt are a mere 2,000 years old.

The most boggling discovery was yet to be discovered. Apparently several stone disks were unearthed from within the complex tunnels of the cave. About 9" across, each had a fine groove filled with a minute band of hieroglyphic charactars not resembling any current recorded text. In the exact center of each was a perfect 3/4" hole. In all, 716 disks were found. The disk closely resembled that of a early phonographic record. The disks were clearly fabricated by intelligent creatures.

Theorists have since concluded this finding to be the cause of the sudden appearance of intelligence in the homo-sapien timeline. Record states that the disks' message was deciphered in 1962 by Dr. Tsum Um Nui. It is believed to be the work of marooned extraterrestrial life.

More interesting are the two tribes that inhabit the surrounding area today; the Dropa and the Han. Anthropologists have not been able to determine their decent as they are neither Chinese nor Tibetan. All inhabitants are between 3.5' and 4.5' tall and between 38 and 52 pounds. They have sparse hair, large blue eyes, disproportionately large heads, and thin bodies.

W. Saitswe, a Russian scientist is the last known individual to have possession of the disks, the whereabouts of which are unknown. He sent to China for them to analyze them in 1968. High concentrations of cobalt were found in the unusually hard disks, along with an unusually high level of rythmic ocsillation. Almost as if they were tuned to a specific frequency. Any sort of fabrication or engraving on these highly metallic disks would have been an arduous task for that time.

Contributing to Senses

Interpretation of our surroundings is an interesting concept; unique in every way to each person. Here, I elaborate on the subject.

Intake, at best, is considered usual discourse or any of several other pre-determined means of ‘things going in’. In a more specific sense, intake becomes the permanent feed through which outside material gets ‘in’ to our minds. Commonly overlooked and seldom parsed by thought it allows the constant barrage of input to our senses.
Missing from this stream is what is present in almost every other case. An engine has filters on its inputs; as do air conditioners and pool heaters. Our intake, however, is filtered only by what means we implement; whether it be by conscious means or not. The flow divides into the five obvious channels and faces interpretation before it is tossed around in calculations then stored away in memory.
As thoughts develop, the conclusions and results of implied actions are forecasted and their subsequent effects on our lives assessed. Here, opinions take form and become the foundations of our personality. This is the heart of it all.

“…life is 10% of what happens to me and 90% how I react to it.” (author unknown)