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Bolt Removal   

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Leverage “Breaker” Bars 

When rebolting, removing aged bolts while minimizing damage to the rock is tricky. Leverage bars of various kinds may be the key to a successful, low impact removal project. Improvisation is key here. Modified crowbars, pipes, lost arrows, knifeblades, or anything that can create mechanical advantage may be useful.

The ideal outcome on any rebolting project is the clean removal of the bolt and a reusable hole. Crow bars or lost arrows can be modified into a “tuning fork”, which can be gently hammered between the hanger and rock to force the bolt outward. This technique is particularly effective with compression bolts and rivets. Rusted wedge bolts have even been pulled this way and stubborn sleeve bolts may need some leverage before they will “funk” out. Sometimes the corrosion is so bad that the bolt breaks off somewhere within the hole. This necessitates a patch and redrilling unless a more advanced method such as drilling and tapping can be employed.

Most wedge bolts will not pull. Cutting the stud with an angle grinder is an option, but this method is dangerous and battery grinders use so much power that most batteries will only last a couple of cuts. The other option is to break off the stud. This basically entails putting so much torque on the bolt that it breaks. This can be done perpendicularly to the bolt with a wrench on a long lever arm by applying excessive clockwise force to the nut, or longitudinally with a pipe modified with a cap that fits over the bare stud and levers it off. Most sleeve bolts require cutting to remove, but it is always better to try leverage due to the dangers of operating a saw at high angles.

Slide Hammer 

A fairly obscure and specialized tool, slide hammers can be configured in a number of ways to assist in bolt removal. Used in the automotive industry to pull everything from dents to drive shafts, slide hammers can be adapted to exert a controlled but powerful axial force on a bolt, in essence reverse-hammering it out. This will not work for all types of bolts or in all circumstances and can result in broken studs, but some of these techniques may help reduce the need for drilling new holes.

Much like “funking” with a hammer and a cable or stiff sling, a five pound slide hammer can a generate tremendous force. The advantage of a slide hammer over traditional funking is that with a properly engineered adapter, force can be centered over the bolt and applied in a controlled longitudinal manner. On the other hand, funking relies on the hanger to transfer force and hangers are all offset from center. This results in torquing with each blow of the funkness that does not occur with a well-configured slide hammer.

Some slide hammers are advertised by their ability to screw into the end of vice-grips. The tension adjustment screw is removed from a pair of vice-grips and the threaded slide hammer end screws in as a direct replacement. This is the easiest method of attaching a slide hammer to a bolt slated for removal. However, due to the angle of the jaws of the vice-grip, this design does not create a pure, straight-line pull.

The ideal setup requires that the slide hammer be welded to the vice-grips with the shaft of the slide hammer in alignment with the jaws of the vice-grips. Many past models have the slide hammer shaft welded about mid-way down the spine of the vice-grip, in line with the center axis of the jaws. Opposing notches cut in the jaws of the vice-grips and potentially customized for the bolt type at issue can aid in gripping the bolt.

Other slide hammer adapters have been be fabricated for a variety of bolt removal projects. They can utilize the threaded shaft and be attached to the bolt or bolt stud in a number of ways. While a machinist may actually weld a connection to a stuck bolt slated for removal, this is not an option in the field. If there is enough stud sticking out of the rock, then the vice-grip method or some other type of custom connector that utilizes the threads may work. If the stud is broken off below the surface, the bolt stud would likely have to be drilled and tapped in order for an adapter can be inserted. This method is time consuming, difficult, and impractical in many circumstances. However, if drilling a new hole is simply not a viable option, the effort to extract a stubborn stud with a specially configured slide hammer may be worth it. As with many other advanced removal processes, creativity and innovation are instrumental in a successful outcome.

Saws 

While not a primary tool for new routers, saws are mentioned because they can be valuable tools for bolt replacement projects. A simple hacksaw can suffice for some purposes, such as trimming bolt studs down, but the time and energy needed to cut steel bolts is high. For this reason, some rebolters use angle grinders. Using an abrasive composite disc that spins at a high rate, angle grinders can cut through bolts with ease. Much like hammer drills, angle grinders are available with battery or gas power sources. Some angle grinders can even be paired with the same battery used in the climber’s hammer drill, making the battery interchangeable and removing the need to carry multiple batteries and chargers.

An angle grinder is the only way to remove some bolts. The main consideration when using an angle grinder, first and foremost, is to be VERY careful around the rope. Just a fraction of a second of contact with a running angle grinder is enough to sever a rope (yikes!). Also, it is very easy to scar the rock, so particular care has to be taken not to contact the rock surface. It can be difficult to cut a stud perfectly flush with the rock, so approaching from multiple angles can be necessary.

Safety glasses are a must with angle grinders, which throw out a lot of sparks. Hearing protection is also recommended. Angle grinders should not be used in arid environments with a moderate or high risk of fire due to the sparks.

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