Bolting installation thoughts (wedge anchors)

[billcoe]

Someone asked me a bolting question via PM, thought it may be better to post my answer for others who have similar questions. Please add information which I've obviously missed or correct those which I am wrong about. I do personally believe that bolts should be utilized as little as possible, but that's another discussion. Unless you folks go there of course.

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Good on ya finding new routes and new areas! It’s a great feeling. On the bolt question, given rock that’s not just loose shit, the 3/8 X 3- 3-3/4" stainless steel wedge anchors you mention would be fine. You mention the Hilti Kb3 bolt. Personally, I think buying on price makes sense as long you make absolutely sure they are ICC-ES approved and you'll be good to go. The construction industry standard (icc-es) has some strong critical checks and approvals much like the climbing CE rating and the Uiaa rating. If it doesn't have the construction rating pass on it.

 

In the old days, almost all climbers used "Rawl bolts" because they were deemed the best (and easiest to install with the hand drilling equipment available) . The were the split shank construction bolt made by the Rawl corp. out of high alloy steel and had a shitload of problems relating to design, size and material. Powers web site link

 

1st issue was the size. They were ¼ diameter and either 1”, 1-1/4 or 1-1/2” long. Due to the design of the split shank, the holding power was not at the bottom of that short length, but closer to ¾ of the way down. All the strength was almost at the surface of the rock.

 

2nd issue is that they rusted quickly. The plating would get scraped at the exact location they relied on for their strength as you banged it in, being high alloy they rusted fast.

 

3rd, the split in the shank needed constriction to cause it to hold, as you tapped the anchor into the small hole, as it started to squeeze the split shank, the pressure would often break the rock at the top of the hole and thus blow out the hole. This occurred more frequently on Basalt than on Granite. At Smith, it was very problematical in the soft welded Tuff but they got used there as well, (along with some other types like the Star Nail-in (Star Dryvins) which used to dot the West Face of Monkey Face and a few other places.

 

 

These little guys, when brand new, would hold up to 2000 lbs on their very best day in ideal conditions. You can check out the strength on the link above as the Rawl Corp was renamed Powers and they still make the little pups. Of course, in rock, conditions even on the same cliff can be hit and miss, let alone some poor pumped out dude in a near death state trying to hand drill a hole with a dull drill bit as his feet are greasing and smeared off. Yet this was the defacto standard and was widely used on most routes and for most anchors throughout the US on 90 percent of climbing routes on non-sandstone. You still run into these little workhorses today, standing up after 30-50 years. The West Face of Monkey 1/4"ers lasted @ 40 years and gradually loosened up till some unfortunate was rumored to have zippered 8 of them out. And even then, the other rumor was that the guys who put them in were taking turns both drinking from a pony keg of beer they hauled to the base and jugging the ropes to bang in some bolts. In soft rock with heavy climbing they still worked for many many years.

 

Failures were remarquably rare elsewhere as well.

 

When 3/8 bolts came into vogue. The length of them jumped immediately as well. Shear and tensile went up by a large factor, but most importantly, the holes were not being banged out and weakened during the installation process, and the strength was coming from close to the bottom of the length being used, unlike the split shank construction bolts. Link to wedge anchor strength Wedge anchors of 1-3/4 length were not uncommon as hand drilling was still in use, and longer than that was rare although there was a bird or 2 using 2” or 2-1/2 here or there in the desert or in weaker rock, but not often around here, and rarely in granite. With the use of roto-hammers, size and embodiment have gotten bigger and it matters less on the installation end. But if you look at the strength of a single 3/8 x 3-3/4 stainless wedge anchor, you will see in order to stress it to the point it will failure, the human body attached to the other end would have most likely not survived that force.

 

I suspect that a 3” long anchor bolt is overkill for 99.5 percent of rock. If you want longer ones because you think the rock is fractured or weak, that’s not a bad idea, I've been installing 1/2 x 7" wedge anchors in a new cliff for instance. Look carefully at the location you are going to put the hole to make sure its not in a fracture plane or loose section. The drill should be perpendicular to the rock as well, so orient it square to the slope so that the nut sits flush.

 

-Check the ASCA site for information, although there seems to be less info than before, it's full of great stuff yet. RC.com use to have a great thread started by RRRadam, who was an inspector in nuclear plants and other critical installations but it looks like he edited it. Might do a search there. Rockclimbing.com

 

 

3rd thing: adding to what’s been said above:

- On the bolt question, given rock that’s not just loose shit, for hand drilling, the 3/8 X 2.25 stainless steel wedge anchors would be perhaps as good as anything you could find. I certainly would use them before the Powers 5 pc in Steel, and the Powers 5 pc in Stainless is way too expensive. The Powers 5 piece in steel will, I believe, be a nightmare in a few years for the brothers who follow us, as you cannot determine via a visual check, when they have turned to shit. All that rusting happens below the surface. Hand drilling in granite though, whew-@ half an hour depending on how bad your forearms are pumping.

 

 

However, it was brought to my attention by Mark Deffenbach that any dumbass climber can easily over torque and thus weaken a 3/8" diameter wedge anchor on a brand new installation. To do it right, a torque wrench should be used to install wedge anchors and the Mfg installation instructions and materials consulted for proper torque, or at least learn what 20-28 foot# of torque feels like with your box end wrench to "calibrate" your arms on a 6-8" box end wrench. So as such, if you don't have a torque wrench, per Mark, 1/2" diameter should be utilized to avoid the potential to over torque and thus weaken the bolt on the installation.

 

I have never heard of anyone installing a 1/2 bolt by hand though, and never heard of a 3/8" bolt ever failing. Ever. I bet it's happened someplace.

 

For hand drilling don't try to bite it all off at once. A sharp bit and a good hammer will get you far along as will strong forearms. Tap tap tap twist tap tap tap twist Tap tap tap twist tap tap tap twist, get a rhythm and let the rebound of the drill do the work. Don't tap too much before twisting, you'll feel it. If you are way out on lead pissing your pants, a light sling can be put over the drillbit right where it is next to the wall once the bit starts to get some depth, to relieve your aching calves and tendons. Don't weight it too much as a snapped drill bit would suck and that use to happen with the 1/4"ers on occasion, it's for supplementary assistance only until you get the hole down where you can put the wedge anchor in. If you are on anything but a nice stance, you'll be peeing your pants for sure, it's a very uncomfortable and muscle aching feeling. Very insecure. When the hole is deep enough, add a few more hammers blows to make it deeper than needed to make sure. Inserting the bolt upside down will sort of work, but better yet is to put some tape on your drill bit when you are safe at home watching the Flintstones to mark how far you need to go based on your bolt length. I have put in bolts without blowing the dust out of the hole, the twisting motion of the bit will clear the hole, butbest to take a McDonalds straw and blow the hole out. Better yet, take a length of plastic tubing and use it instead and you will be further away from the rock when the dust poofs out at ya. They make brushes as well, and using both the brush, the air hose and the torque wrench will pretty much guarantee a perfect install as long as your hole is deep enough. You should have already put the nut and the hanger on so the nut is flush with the top of the anchor stud, then slowly tap in the bolt until it is flush. Slamming the bolt in may be what causes spinners on clean holes and it causes rock dust to slick up the insides again. Some brands are more susceptible to this. Believe me, you don't want to do a spinner when you're at a crux or planning on rapping on it! Tap it in then set it by wrenching it to the recommended torque and you're done baby! Clip that puppy and hang like the crybaby motherfucker you feel like......err, wait, I don't know where that came from, I mean clip and send, that’s it, clip and SEND BABY! (Note to self: No hanging damnit, no crying damnit, no peeing the pants.... again.... damnit.)

 

 

A heavy hammer is nicer than a light hammer, the Kong Eagle is one of the best for this, they make 2 versions the heavy one rules. A5 if you can find one without mortgaging your left nut, a Forrest wall hammer, or Black Diamond are all almost as good. Stay away from some of the real light European hammers (Bonati, Salewa) which are really designed to be carried up easy 3000' faces in the alps to just reset a piton or 2. You'll be working your ass off to get a hole drilled with one of them and wacking in a 3/8" bolt is too much work as well. If you want to save some money, borrow your granddads ball-peen hammer, drill a hole in the handle the thread some cord so you don't drop it and you're good to go.

 

Always use stainless steel wedge anchors too. Even in Eastern Washington and Oregon. Seriously, otherwise, someone is going to have to replace it, and you can't get the 5 pc out within a few years in western Oregon with a wrench cause the shit rust and weld the bolt to the threaded wedge insert inside. You wind up snapping the head off and then you have a grade 5 bolt which you ain't drilling out easily bubba, so you have to put the next STAINLESS bolt next to the snapped off 5 pc and cover the shithole with 2 part epoxy.

 

The lifetime of the 3/8 x 1-3/4 I was handrilling in the real wet part of Oregon have all lasted at least 30 years, and although I think they have all been replaced with stainless recently, they were all holding up great, but showing some visual rusting. With that as a backdrop, the lifetime on 304 stainless in a non-marine environment must be well over 50 years somewhere, and the 316 easily 100 years. No one knows yet! If you are going to be anywhere near the coast, seriously consider 316 SS as the minimum, and put on a tight rubber washer first, so that it is under the flatwasher and nut assembly. That’s where stress corrosion cracks happen. Or best yet, especially in Limestone near the ocean which has its own corrosion issues, the insanely expensive Ushba Tortuga Titanium glue ins.

 

regards to all

 

bill

 

[sweatinoutliquor]

Nice write-up Bill. If folks are going to do it, they may as well know what tools they need to do it right.

[kevbone]

Bolt it and they will come.

[pink]

or just throw a porn in

 

 

[Peter_Puget]

Just a few comments.....

 

1) 1/4" SS bolts break very easily..don't use them.

2) On steep ground after hanging around forever drilling a hole you might be tempted to hang on a bolt as you finish tightening the nut..don't it is very easy to beak even a 3/8" bolt doing this.

3) Bolts do break. A friend of mine took a long grounder when a big one in Spain broke.

4) Placing a 5 piece on lead can be a real PITA. Same with certain wedge anchors. If the wedge/sleeve gets caught up while the bolt is being driven in your screwed. Don't just jam the bolt in the hole and start pounding.

 

 

 

[RuMR]

2) Witness Max Dufford landing on Devinder after tightening a bolt on Oxygen while hanging on it!!!!!

[dberdinka]

I recently acquired an old rotary hammer and a box of Hilti Stainless Steel KB3 wedge anchors. These anchors require 20 ft-lbs of torque at installation.

 

In an effort to learn how to place these things correctly, last night I went to the local hardware store and rented a CALIBRATED torque wrench and purchased a handful of cheap 3/8” wedge anchors (50 cents vs ~$2.50 for the KB3). Then I drilled a dozen plus holes in a dog-size granite boulder in my backyard and started placing bolts using a ratcheting box-end wrench that about 6 or 7 inches long.

 

After the first bolt or two I was able to consistently get > 20 ft-lbs and < 25 ft-lbs of torque on each bolt. For me (no one would describe me as strong) this essentially meant cranking down on the nut as hard as I could using one hand without putting my body weight into it.

 

After burning through the cheapo wedge anchors I placed two of the KB3. These anchors snugged up much faster than the generics but I still was reaching the proper torque.

 

Then I attempted to snap all the bolts off by over-torqueing. The generics snapped easily, generally at anywhere from 40 – 50 ft/lbs of torque.

 

The Hilti anchors were far stronger. After exceeding the 75 ft-lbs of torque the torque wrench maxed out at, I continued to crank on them with a breaker bar. The rock fractured across the bolt holes before I was able to snap off the anchors! Note that both holes were probably within 6 inches of the edge of the rock, and the rock was starting to look like swiss cheese from all the holes I drilled.

 

The conclusions I drew are

 

1) With a little practice it is easy to apply the appropriate amount of torque (20 ft-lbs) to a 3/8” wedge anchor using a small (6”-8”) box end wrench. For me that meant tightening it down as hard as I could using a single hand/arm without leaning into it.

 

2) Using the small (6”-8”) box end wrench it would be next to impossible to over-torque a quality 3/8” wedge anchor unless you're superman. See billcoes comments above. Not so for the cheapos from the hardware store bin!

 

3) The KB3 exerts a tremendous amount of pressure on the rock surrounding it. Only place in very solid rock well away from edges and fractures (ok so that’s obvious, but listening to the boulder sllooowwlly crack in half certainly reinforced the idea)

 

This little project cost me about $20 for the rental and the bolts I placed. The knowledge gained seemed well worth the time and effort.

 

[RuMR]

dberdinka,

 

it would behoove you to request a hilti catalog and read through the installation section and the design section...there are all sorts of factors that reduce the allowable capacities of the botlts...one that you mentioned was edge distance...while these values given in the catalogue are for competent concrete (3000-4000 psi, if i remember right), the trends are the same in rock...not the values, the trends...

 

the other consideration about overtorquing is that torque, by its nature, induces shearing stress into the bolt. One component of a fall is shear, the other is tension from pullout action. The torque stress and the shear stress are additive, so while you broke your samples in pure torque, they would have failed at a lower, but still overtorqued, value had shear been applied to them as well...ie, the max/devinder example i mentioned earlier...

 

shoot me a pm if you have anymore questions...

[JosephH]

One more thing - over the past four years I've seen just a ton of bolts where the hole was not drilled perfectly perpendicular to the rock. This results in some staggeringly lousy installations with the nut or bolt head cocked way off from laying flat against the hanger.

 

If you're going to go to all the trouble of assembling the stuff to put in a bolt, then try to get this part right as it is critical to a solid installation. If you're rapping with a power drill then don't descend too far below the hole as I suspect most of these abortions result from flagging forearm strength and drooping drills. Stay a little high where you can see what you're doing and have better control over the drill. If hand drilling on rap you'll need to descend a bit lower, and you have to really pay attention to the drill position relative to the rock for the first 3/4 of an inch or so. Hand drilling on lead - kudos - you do the best you can, just try to keep this in mind while you do it. Also, take a moment before drilling for a good look at the [micro] terrain and do it from several perspectives to insure you have some references for drilling perpendicular as sometimes it can be hard to judge - set the drill in place and then double-check it from several angles before pulling the trigger and keep checking it until the bit is driving home on a course that can't be changed.

 

And I second Bill's advice; if you're going to bother at all and value your new line, then pop for stainless bolts and hangers - plated stuff is going to have to be changed out way too soon and borders on lame at this point in the game.

[Rad]

Good data Dberdinka - welcome to the darkside!

 

It would be interesting to do your test with old school star drive or other bolts. The results might be quite shocking.

 

I have been able to over-torque the KB3 with a 10" handle on a socket wrench, and I know you're stronger than me. 20ftlbs is not that hard. I did pony up for a torque wrench (found one for $50) to check. Like you said, though, once you know how hard is right the torque wrench becomes superfluous.

 

I've borrowed a Yos hammer and that works great, but I find a standard claw is also useful for cleaning and is much lighter to carry around, and with a few more taps it gets the job done just fine. Yos might be the better choice for drilling by hand, but again, you have to carry its extra weight.

 

I've tried KB3 and Rawl 5 piece. The latter are a pain in the arse because the fall apart in my bag or elsewhere. The KB3 are pretty idiot-proof, and since I'm an idiot that's what I use. MEC sells them pretty cheap so there's no reason to buy them at Home Depot and risk that they aren't tested to the same specs. Stainless is the way to go unless you want rust.

 

Hopefully the routes you put up will become popular, so it's worth a little extra effort to do things right the first time. Poor bolt placement or sketchy bolts are annoying on any route.

[dberdinka]

Getting all the shit together to do it right has resulted in just an endless dribble of $$$$$......

[JosephH]

Getting all the shit together to do it right has resulted in just an endless dribble of $$$$$......

 

You got that right...

 

[Rad]

Getting all the shit together to do it right has resulted in just an endless dribble of $$$$$......

 

True, but that can be said of most activities.

[markwebster]

When I was actively putting up and maintaining routes I went to a gravestone shop and asked if they had any discarded granite blocks. Got a nice one for free, about a one foot cube of polished high quality granite. I practiced drilling, placing and removing (with a crowbar) the bolts until I had it down. It's amazing how strong those suckers are when placed right.

 

Gravestone still sits in my yard 30 years later...bunch of bolts sticking out of it.

[LostCamKenny]

When I was actively putting up and maintaining routes I went to a gravestone shop and asked if they had any discarded granite blocks. Got a nice one for free, about a one foot cube of polished high quality granite. I practiced drilling, placing and removing (with a crowbar) the bolts until I had it down. It's amazing how strong those suckers are when placed right.

 

Gravestone still sits in my yard 30 years later...bunch of bolts sticking out of it.

 

A practice rock... Nice!