Tuning Fork - Bolt Removal
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There are dozens of rusted mechanical bolts at our seaside crag that need to be removed and replaced. From what I understand, the bolts are mostly 3/8" Fixe, not sure if wedge or rawl, definitely not button-head. What I need, apparently, is a #4 BD Lost Arrow bored out to look like a tuning fork. |
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If they're 3/8in with exposed threads (Wedge Bolts) the tuning fork MIGHT work but pretty unlikely. The tuning fork was really developed for removal of old 1/4in compression bolts from BITD. 3/8in wedges are a whole other beast. Seaside you're looking at likely replacing with either Ti or Duplex glue ins. It depends on the exact location but assume SCC is an issue to be safe. From the reports I've seen, you'll probably end up chopping the rusted studs, patching and drilling new holes for the glue ins. |
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mattm wrote:If they're 3/8in with exposed threads (Wedge Bolts) the tuning fork MIGHT work but pretty unlikely... From the reports I've seen, you'll probably end up chopping the rusted studs, patching and drilling new holes for the glue ins.How do we chop them, then? Hammer + screwdriver? |
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Nate Ball wrote: How do we chop them, then? Hammer + screwdriver?IMHO, when replacing wedge bolts, always worth it to put the tuning fork on first. 9/10 times it won't extract the bolt, but it moves the stud out a ways. A hacksaw blade wrapped with tape at the ends will cut the stud pretty close to the wall. I like to cut a bit with the hacksaw blade, tap with the hammer and expand the kerf, repeat. Usually the stud shears off pretty nicely after it's been cut ~2/3 of the way through. A pin punch is a nice way to drive the remaining stud back into the hole. The reason I use the tuning fork regardless is that a lot of the time the hole isn't drilled with any extra depth. If you pull the stud out a little bit, chop, then drive it back in the hole, you'll have a little bit more of a divot for patching. |
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Locker... |
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Locker. It's simple: don't be a jerk. Thanks for the link. |
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supertopo.com/climbers-foru…
This thread shows Rogers modifies forks, which are much larger and would most certainly work for a 3/8th stud in some fashion. You will need an angle grinder and water or coolant for the cutting process. I have removed 3/8th stud bolts with my modified crowbar. Pretty cheap to make, but there are no guarantees in bolt removal. If all else fails, beat the stud back and forth, chop it flush and punch it back in below the surface, then patch and drill a new hole. |
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Contact Mark Hudon on this site and he will make you a set of tuning forks and give you all the beta you need. |
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Easiest way to chop a wedge is simply crank on the thing until you over torque it and it snaps off. Usually it both pulls the bolt out a bit and snaps off below the surface so you can tap it in and patch over it. No tuning fork needed. |
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I have pulled 4 of those. They were 2" or 2.25" long |
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Locker wrote:I wasn't being a jerk. I was being, me!Guideline #1: don't be a Locker ;) |
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Matt N wrote: Guideline #1: don't be a Locker ;)HA! |
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Hey Nate, |
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One other thought: The P38 looks like it's a 304 stainless. Are they corroding at your seaside crag? What are you going to replace them with? |
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Nate Ball wrote: This is what we're dealing with: Petzl P38's. No nut or bolt to torque on. 12mm, almost half-inch. Then what? I'll get in touch with Mark.I heard tell you can pull those kinda bolts by grinding off the top, which might release the pin. Maybe pop them after grinding with a hammer to loosen them up, then, use a tuning fork under the hanger. Or, core drill them. Stainless seems softer than grade 5. You'd end up with a much bigger hole, but, with the larger diamater Ti bolts you'll be gluing in, shouldn't be an issue... |
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Mike McHugh wrote:One other thought: The P38 looks like it's a 304 stainless. Are they corroding at your seaside crag? What are you going to replace them with?I'm not sure about the P38 specifically. Surely there are many others scattered about of all different types. Some of them are snapping off under falls or even body weight. They have been mostly replaced by 316 glue-ins (which are also suspect), though the mechanicals were left in the wall. This also means, unfortunately, that we won't be replacing them with titanium any time soon. |
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Jesse Zacher wrote:. First, please consider the conceivable damage you may inflict on the rock while trying to remove the bolt.Exactly. Plus there is not really anything to beat back and fourth, other than the hanger. Stud/ nail-drive bolts are fairly low profile and it would be pretty hard to do anything useful with a hammer. Unfortunately those bolts are very hard to remove. As others have said, the best option is to cut it off or drill the center out. An angle grinder is an option. Another option is to use a cutting torch which will get the job done pretty fast. However, working with a torch at height is a pretty serious risk. You MUST use two ropes, and the working line should be heat resistant (Beal makes fire-retardant ropes and heat shields for ropes). You also have to cover your harness in a thick leather welding jacket to ensure you dont melt your harness. It's pretty serious work for sure and it is really only feasible in a desert-type environment where you wont burn everything to the ground. You may want to consider replacing the bolts with titanium so you dont have to go through this again in the future. If you need some Ti bolts let me know and I can put you in touch with a supplier. |
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We´ve replaced a fair few of these as they were popular for a while in Europe. |
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Okay, so to summarize... |
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Our tuning forks are ONLY for 1/4" bolts (6mm), they will bend open and snap on 5/16" (8mm) let alone something huge like a Long-life (12mm). |