The Book of Installing Mechanical Bolts

“The more you twist the head, the more the nut gets sucked up.”

The Bolting Bible

This is free resource by HowNOT2 and our way of contributing to the community. It's nice to understand what you are clipping and trusting with your life, even if you never plan on installing or removing bolts. We also believe that if you are going to spend time and money to bolt something, you should do it well.

This book is in a blog format. This page points to all 17 chapters, and the end of each chapter points to the next.

A downloadable PDF is available HERE.

Pre-requisites

Mechanical bolts aren’t rocket science, the basic idea is that you smash it in and tighten it.
Assuming you put in a good hole (BOOK OF HOLES) and have the right metal (BOOK OF METAL) and know what hanger you will use (BOOK OF HANGERS) and understand what mechanical bolts to use if any (BOOK OF MECHANICAL BOLTS) then lets talk about how to put them in.

Being Flush When You Finish

On sleeve bolts, a hex head attached to a rod will suck up a flanged nut at the bottom. The rod/shaft doesn’t get any higher the more you tighten it; all the magic happens in the hole.

But then there are wedge bolts where the rod/shaft is being pulled out of the rock as you tighten the nut. It's on every wedge bolts though some sleeve bolts work this way too. The nut should be installed when you hammer it in, but you don’t want to hit the nut because that means you are putting all the force on the threads and that can damage them. However, you don’t want the rod sticking way up when you are done, so you want to start the nut as high as you can get it, without actually hitting it. If the rod is sticking out far enough, it can hit the gate if your carabiner gets rotated and literally open it!

Get It Together

It is important to install the hanger onto the bolt BEFORE hammering it in. If you forget to put the hanger on, then you may not be able to pull it back out or accidentally put it in too deep. If you can partially remove it like the Power-Bolt, then you risk debris getting into the threaded cone at the bottom. If you take the nut off of Fixe’s Triplex bolt, then the whole rod can fall into the hole and probably deep enough to where you can’t get it out because there would be no way to grab it. So, install the right hanger to the bolt BEFORE hammering it into hole.

Sleeve Bolts

Place the bottom coned nut so it is just touching the sleeve but don’t pre-expand the sleeve (see pic above). If it goes in really really easy, you may have a hard time getting it to tighten because the entire bolt and all its parts are spinning in the hole. If it is a bitch to get in the hole, then your hole is too small or you spread out your flanges too much. You'll risk breaking or compromising your bolt, and the harder it is to get in a removable, the harder it will be to get it out!

Then tighten it. All bolts have a specific torque pressure they require to achieve the ratings that the manufacturer claimed. Torque wrenches are not expensive but can suck to take on a long hike.

If you don’t use one on the mountain, at least use it on some practice bolts at home in your backyard so you know what it should feel like. If 25 foot lbs of torque is required and you have no freaking clue what that feels like, use a small to medium wrench and pull until your face scrunches but not so hard that you grunt.

If you don’t tighten it enough, obviously the risk is that it could come out. When I tensioned bolts from 25 to 35 torque lbs, I was shocked how much umpf I had to give it. There is a limit, like everything, that if you really really tighten it that you compromise its integrity by breaking the bolt or stress cracking it. A fun experiment is to try to pull out your test bolts after hardly tightening it at all. It is amazing how well they hold. However it is important that they are properly tightened.

Hangers want to be a certain direction depending which way you pull them. You don’t want to randomly place your hanger and then, when tension is applied to it, forces it to spin to the correct orientation while under pressure. Keep in mind the proper orientation might look diagonal to your eye but you can clip a carabiner to it, pull it in the direction it will be used and finish tightening your bolt.

Wedge Bolts

To install, start in the same way as the sleeve bolts by putting the hanger on the bolt before hammering. These too require a specific torque. Tighter isn’t always better. Be sure to line up your hanger with the direction you will pull it and wrench it down.

The rod will stick up higher than the nut after you torque it so start with the nut as high as possible without hitting it with the hammer. Make sure the wedge is expanding immediately and not sliding up the hole as you tension the nut 20+ rotations, leaving very little bolt left in the rock. You can feel if it is getting tighter and expanding in the hole.

Ugh, why is it doing that? (FAQs)

Why is my sleeve bolt just spinning and not getting tighter?
The hole is probably too big, the entire bolt and all its parts are spinning inside. The nut at the bottom of a sleeve bolt needs to stop spinning, so give friction to the nut by pulling up against the sleeve while you tighten. This is done by pulling up/over on the hanger. If it comes out too much, after you get some progress, hit it back down flush against the hanger and rock and finish tightening it.

My bolt won't go in all the way, why?

Keep in mind that if your hole is too shallow, the bolt obviously won’t go in all the way, but that means the hanger will be spinning because it isn’t secured to the rock. That doesn’t mean it will blow out the hole if you use it, but it is considered sloppy and I don’t know if I would trust a bolt that I knew nothing about if the hanger is loosely spinning. If you really goofed, and it is sticking way out, then it could leverage the bolt, breaking it at a much lower force. See the Book of Pulling Out to learn how to remove it to drill it the right depth.

Why is the wedge bolt rising as I tighten but not getting tighter?
The clip at the bottom is either spinning with it or the wedge at the bottom is lifting the clip instead of expanding it. The clips commonly have 2 bumps on them to give some friction along the rock and so it shouldn’t do this, but if that’s your problem then try to pull up on hanger while tightening but if you try to hammer a wedge bolt back down because it got to high/extracted, it only knocks the wedge out of the clip and you are more or less starting all over. Hole size is pretty important here.

Why is it snug and tightening but won’t get solid?
If you are sure the sleeve or clip is expanding and it is snug but not increasingly getting tighter, then the rock is shit and it’s expanding the rock (I have had this happen to me before in Iceland). This needs a deep glue in (in a fresh hole)

What are those plastic parts on the sleeve bolts?
Sometimes there are spacer sleeves or bushings or compression rings that are made out of plastic. These just separate the parts and it’s not holding any force but helps with installation. The powers spec sheet states, “The Power-Bolt is also designed to draw the fixture into full bearing against the base material through the action of its flexible compression ring. As the anchor is being tightened, the compression ring will crush if necessary to tightly secure the fixture against the face of the base material.” There is also a plastic star shape below the nut on some bolts and that helps with the loose nut syndrome, something we all try to avoid! Leave them on there, they help. Don’t worry, they aren’t the parts that hold the bolt in the rock.

Is it OK if the rod sticks up higher than the hanger.

Assuming you still have enough bolt left in the rock for it to be super safe enough, it cosmetically looks bad and leaves any wandering climber curious as to how much bolt is actually embedded in the rock.

If it sticks out too much it could hurt someone or be an unclipping hazard as the gate would be opened if the carabiner rotated. I recommend loosening the nut, hammering it in again and trying to get it to seat deeper. Just having the tip in the hole isn’t going to satisfy everyone involved!

Real life shit

This video is of a bolt breaking during a highline whipper. Andy Lewis set up a highline for an Alex Mason’s Red Bull eclipse shot and had to use some existing shitty bolts. They were shitty zinc plated bolts that corroded enough to snap during approximately a 5kn whipper which was spread out over that 3 point anchor probably only putting a maximum of 3kn on that bolt.

Buying Guide

As nice as it would be to write in this book, “Just use this 1 bolt”, there is no perfect bolt as each has pros and cons. We want you to know HOW to buy bolts and NOT tell you WHAT to buy. Consider the following when reviewing bolts you see online...

Length is TOTAL bolt length for mechanical bolts. If you have a 4 ½” bolt, you may only end up having 3.75” embedded in the rock when you are finished.
Some bolts are certified with EN 959:2007 certification or CE/UIAA or some construction certification. And some are not. Go with a reputable company in either case.
Don’t buy zinc plated or plated steel or galvanized bolts.If you can’t afford stainless, don’t install bolts. PLX stainless is awesome but fading out for the new standards of 316L SS.
Read the spec sheets and know what the torque specs are (how tight that bolt is supposed to be wrenched down).
Be sure your hanger is made of the same metal as your bolt so you don’t get galvanic corrosion.

These companies sell mechanical bolts that I would take a whipper on.

BoltProducts is based in Europe and Team-Tough is their distributor in North America. Their products are quality. The only mechanical bolts they sell are wedge bolts.

Fixe Hardware has great selection including Powers sleeve bolts but unfortunately they sell PS (plated steel) which technically can be used in the driest of deserts but it ought to be made more clear as they get installed in wetter areas all too often. They still have some PLX products but are phasing them out for 316L SS. All their products are bomber. Manufactured in Spain and distributed in the US.

ClimbTech sells Powers sleeve, wedge and removable anchors. Unfortunately they also sell PS Powers!?!? US Based.

Vertical Evolution has a single mechanical bolt option that comes in 8mm (too small), 10mm and 12mm… in 316SS or galvanized??? Most of the bolts on their site are glue in bolts. Based in Italy.

Climbing Technology has a great selection of HCR (PLX) and 316L mechanical bolts. Based out of Italy and France.

Raumer sells wedge and double wedge of all sizes. Based in Italy. HowNot2 stocks some Raumer products. CanyonZone is European Distributor.

Petzl sells quality bolts but they aren’t cheap. Sold everywhere.

The Power-Stud was a great 304SS wedge bolt that is about $3 each and is very accessible and comes with a SS washer and nut. In our Bolt Buster shear tests, they will snap at 60kn, higher than almost any hanger you can buy for it.

Confast’s “American 316SS Thunderstud Anchors” are a good price at $5ish each with washer and nut included.

What NOT to Buy

I am NOT convinced Keith Titanium makes bolts that are OK to use but my OCD won’t let me exclude it from this book if I’m attempting to make a complete guide to bolts. I tried buying some but they supposedly don’t sell these in the US and after researching the product this is what I found. Someone couldn’t screw on the nut when they bought it because the threads were poor quality.

The website claimed UIAA approved and the UIAA took action and it is no longer on their website. It is not certified to EN959 either. Tested by a third party said this is NOT a titanium alloy like the website states but is commercially pure and not an alloy. The nut and bolt threads appeared cut and not rolled (rolled is stronger and holds up to fatigue). The wedge piece is floppy so a large portion of the bolt gets pulled out of rock when tightening leaving a shallow embedment depth.

What's Next?

Chapter #9 - The Book of Glue In Bolts