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The Book of Installing Mechanical Bolts

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

The Bolting Bible

The Book of Installing Mechanical Bolts

Welcome to our free course as our way of contributing to the bolting 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. Also, if someone is going to spend their time and money to bolt something, I assume, they probably want to do it as good as possible. Hopefully the Bolting Bible gives you the tools you need to do a great job. Get it?

Our courses are A-Z content in blog format, glued together with an over arching blog we call a text book. A blog format is easy to read, easy to update, and easy to translate. Be sure to begin at the TEXTBOOK and at the end of each episode we'll point you to the next.



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.


Believe it or not, bolting companies are not lining up to sponsor us; mostly because there is no money in such a niche industry. $1 per episode helps a ton and so does grabbing MERCH if something grabs your eye. Lots of designs and options.

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.