Cutting old bolts to remove them

What is your preferred way to cut off old bolts flush with the rock?

I've heard of people using angle grinders but that sounds terrifying while dangling on a rope.

Has anyone tried with an oscillating tool?

Heliodor Jalba wrote:

What is your preferred way to cut off old bolts flush with the rock?

I've heard of people using angle grinders but that sounds terrifying while dangling on a rope.

Has anyone tried with an oscillating tool?

I would rather use the grinder with a diamond wheel. I have cut stainless bolts with my Milwaukee oscillating multi-tool, but it tore the bit up on the one bolt. Those blades are just not thick enough to chop a series of bolts. If you apply pressure slowly with the grinder wheel and get it to start biting, it chops it pretty quickly and smoothly. 

Heliodor Jalba wrote:

What is your preferred way to cut off old bolts flush with the rock?

I've heard of people using angle grinders but that sounds terrifying while dangling on a rope.

Has anyone tried with an oscillating tool?

I’ve used both and both work fine. A good tactic when using cutting tools on a rope is to attach a long swaged cable to your belay loop and a jumar 5-10’ above you so if you cut your rope, you don’t die. But if you do a good job at positioning yourself and work carefully, it isn’t that hard to not cut your rope.

Either way, unless you’re also core drilling, (or the placement doesn’t make sense and the bolt needs relocating) you really shouldn’t ever be doing this.  I’ve found it’s about a 1 in 200 situation for me.  If you’re not going hole for hole, you’re blowing it. (Hopefully you already know that and are just dealing with that 1/200 situation)

I'd think a rotary tool (Dremel) with a cut off wheel would be the safest, cheapest, lightest and easiest option.  I've never had to cut off a bolt on a cliff but I've cut off other bolts with this setup in other situations.  An angle grinder for a 3/8" bolt seems super overkill and bits for oscillating tools are expensive and just don't work that well compared to a spinning disk.

Heliodor Jalba wrote:

What is your preferred way to cut off old bolts flush with the rock?

Why cut off the bolts? Assuming that you can't remove them, if it has a hex head or hex nut, simply put a socket on it with an 18" breaker bar.  1/2" drive, 6-point impact socket preferred. Over-torque until the bolt snaps. Tap the remaining stud below the surface, then patch the hole.

I don't know your exact situation but I have found that shearing them (studs) with a breaker bar works well, they usually break at the rock surface. Way simpler than dealing with a grinder and your not going to cut your rope. Obviously there a situations were the grinder is the only option though...

Grinder is the way. I use an 18” section of radiator hose as rope protection when I’m working, and it’s really not bad if you’re hanging in front of the bolt right. 

I use a Milwaukee Tools rotary tool with a cutting wheel on the rare occasion I need to cut a bolt.  But cutting a bolt really should be the last resort, after all efforts to remove it have been exhausted.

I work on double fixed lines always when rebolting:  A work line and a safety line. Why double lines?  It's not just your tools accidentally cutting or damaging your rope that you have to worry about.  You also must be aware that some unseen edge or crystal may be slowly sawing through the rope as you dangle there on it for extended periods.  Even the best efforts at providing abrasion protection on the rope can often miss potential abrasion points along the line.

Mikey Schaefer wrote:

I'd think a rotary tool (Dremel) with a cut off wheel would be the safest, cheapest, lightest and easiest option.  I've never had to cut off a bolt on a cliff but I've cut off other bolts with this setup in other situations.  An angle grinder for a 3/8" bolt seems super overkill and bits for oscillating tools are expensive and just don't work that well compared to a spinning disk.

I had a Dremel tool bought exactly for that reason. Really, the battery and wheel are not up to the task of doing real work. A grinder is superior and really not unmanageable if you learn how to handle one. 

I’ve got the Milwaukee m12 which might be better than an actual Dremel?  Batteries sure aren’t a problem as it uses standard M12s.  I’ve hung drywall in a couple houses and used the Milwaukee to cut out all the doors, windows and outlets.  I’ve also had two different Milwaukee angle grinders and have used them enough to burn one out (lots of cast iron sewer line removal and finish tile work).  I’ve used both tools a decent amount to cut off random metal bits and pieces.  I guess I’ve just found the rotary tool to be much more precise and overall easier to handle.

Did you get quality cut off wheels or cheep amazon ones?  Maybe that was part of the problem?  Regardless sounds like we’ve had different experiences with the two tools.

When one says Dremel I  typically think tiny homeowner hobby tool with cutoff blades that explode with any slight tweak. A 4.5" grinder with a diamond blade is not typically going to explode and imbed shrapnel into your face. A hammer with a nice cold chisel is fast and easy too.

And like Brian said, two ropes is not a bad idea, I've had a rope cut halfway through just while rapping down something to look at it, no tools or swinging around involved.