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Bolt Identification
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Hey y'all, just wondering if you might be able to give me a best guess on what we're looking at here. Sorry it's a bad photo, I should be able to provide better photos soon.  For reference this is on the route Peace, on Medlicott dome in Tuolumne Meadows. From what I can tell there is no obvious glue and I'd guess they're just old eye bolts pounded in there. Anybody have experience removing these? Thoughts on current hole diameter/quality and potential need to upsize/redrill? Think they'll come out if I twist with a prybar? Do I need a Hurley sr? Would sleeve bolts work in the holes or should I go glue-ins? This route is historic and should be done up right for the future. No room for error. I'd love to hear from someone who has actually replaced these type of bolts in Yosemite or on a Kauk route and may have experience with what I should expect. EDIT 8/20/24: See new thread with updates and a better process-- |
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Apparently they're an eye bolt version of a Taper Bolt: |
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Those are Taper bolts, placed by Bachar (he was a big advocate of using Tapers). I replaced identical ones on Grenade Launcher. They can easily be unscrewed since it's just a lead sleeve at the bottom. Drilling through the lead is super painful, and the only way to drill through it reliably is by up-sizing to 12mm or 1/2" (since the rock blocks the drill from getting stuck in the lead - it keeps the impacts short and drills out the lead along with the rock). Upsizing to that size is obviously a big pain when hand drilling. It's also possible to simply unscrew the bolt and place a super short stainless wedge bolt. I would NOT do that for those pro bolts - I did it for one of the anchor bolts on Grenade Launcher, but the other one I up-sized to a Long-Life (since they are 12mm and very short). The short wedge bolt had a very small margin for error for the sleeve to catch (luckily in that case it did). Someone might have a good idea or trick for drilling out the lead sleeve with a hand drill - anyone? I'm pretty sure that the lag bolt trick (used for lead sleeves of 3/8" Star-Dryvins) won't work since the lead is tapered. Best to use a dust mask since inhaling lead particles is not so smart... |
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Hey Greg, if I unscrewed one of the eyebolts would I be able to put it back in? Or is this a situation where once you open the can of worms you better be ready to fix it then and there? Do you think this would be removable with a funkness, mega tuning fork, or Hurley sr? |
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You could unscrew the eye bolt, put a guide rod in it's place, and then core drill it with those morse core drill bits that greggerman shared. It's not hand drilling but it's quieter than an sds drill |
matt hoffmanwrote: NO - Taper bolts are super torque sensitive - slightly too much and it rips out the lead sleeve threads. Even with correct torque I doubt they were ever intended for unscrewing and retorquing, the steel threads into lead are likely to just cut threads however they want despite the previous threads. On an eye bolt like this, getting the torque correct to begin with is super difficult, since to end up with vertical orientation you need to start tightening from the correct angle (which may depend on how the outside of the lead sleeve "bites" the rock, and the rock friction, how clean the hole is, etc). Nope, not going to be removable with those tools. The end of the bolt tapers into a lead sleeve (hence the name). Let me see if I can find a sample Taper bolt for some photos (they are still made in hex head at least). You will be shocked that anyone ever thought this was a good design! |
cieneguita wrote: Hmmmm....maybe, but there is a LOT of competition for that title!!! |
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What about just a normal metal drill bit in a hand drill (the rotary ones with the crank, not the rock ones we use). You could then drill the holes deeper (with a rock hand drill) if needed and place bolt products 8mm slb. Just an idea never done it. Also I'm pretty sure trying to rescrew one is a very bad idea, the lead threads fail very easily This is what the hex version looks like  |
 This is a 1/4" one. They make some sense as a temporary bolt. On a slab. To be upgraded right away. I don't think the 3/8 ones make much sense as a 2 1/4 ss 5 piece is a forever bolt in good rock. I agree that a regular metal bit might drill the lead out. Taking small bites at a time? |
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Looks like I'll be ordering a box of these things to practice on. Last year someone told me one of these bolts was "loose" so I wonder what that means. |
matt hoffmanwrote: If A taper bolt is loose it is next on the list for upgrade! |
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The PDF does say you can simply unscrew them and then re-torque them. Greg's advice to not try that seems wise. The pullout force relies on the bolt being currently torqued (the sheet says 40 ft lbs!), so if it's at all loose you'll probably get the strength shown in the video. |
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I purchased 10 3/8"x3" hex head taper bolts to fuck around with. I will be attempting to remove them with minimal effort/time using Wilderness appropriate tools to the point where I can reuse the holes and hand drill them deeper. I will post updates. |
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Matt, Btw, the cone/plug of the Taper bolt is made of a zinc alloy, most likely zamac, not lead. The misconception that it is lead likely goes back to the very old use of lead tape or sleeves with screws. Those were commonly called "lead heads". Lead probably became obsolete in the 1960s. I believe some of the old Star "Dryvin" nail-in anchors used lead sleeves. Modern nail-ins use zamac. Zinc alloy should drill easily with a HSS (normal high speed steel) drill bit on a hand-crank "eggbeater" drill. Looking forward to hearing about your removal experiments. |
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in the jenks video the bolts pulled quite easily in tension and brought the sleeves with them. in experimentation mode, i'd try: 1.) something like a hurley sr 2.) unscrewing original bolt, then using a threaded stud with a jabr. downside here is that the threaded stud is most likely not tapered, meaning that there's more of a chance of busting the sleeve somewhere along the line (although the remainder may still come out also) |
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You could cut the hex head off one of the 3/8"x3" hex head taper bolt, and weld a threaded rod to the tip (or just cut new threads with a 3/8" die) for use with Hurley or yabr |
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Would it be feasible to pull the bolt and drill a short glue in directly above it? Should be easy to patch the hole regardless but it’s even easier if the eye of the glue in is partially covering the hole. Fill the old hole with glue as well.
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Tal Mwrote: This is a high visibilty wilderness situation so re-using the existing hole is the best game plan. |
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Hmm... grind (aerosolize) out potentially a ton of holes full of lead dust. Do a risk hazard assessment beforehand... what happens to the dust when it gets blown out? Does it get on you rope, clothes, equipment, holds, etc.... If you're like me Ive never decontaminated my climbing gear. I would be putting a new hole in and starting fresh in a situation like this. We need motivated folks like you to still be rebolting in the future which I suspect is more difficult with nervous system injuries.
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timothy fisherwrote: This is effectively re-using the existing hole - in my experience, the eye of the glue-in will entirely cover the old bolt hole, which should also still be patched as well. If done correctly, everyone except the rebolter shouldn't even be able to tell the holes weren't used 1:1, and the bolts would only have been moved a fraction of an inch. OP - do you know the exact dimensions of the hole that will be left behind once the stud is removed? Would it be possible to glue one of these directly into the leftover hole? https://www.team-tough.com/raumer-superstar-%C3%B88x80-a316l |
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Found one! This is an identical Bachar taper eye bolt from Grenade Launcher (assuming he didn't find and use multiple lengths - very unlikely). 2.25" 5-piece on left, 2.25" stud bolt on right, plus an 8x80mm Raumer Antrax (which are fine in 3/8" holes). The sleeve (which I guess is a zinc alloy, I'd always been told it's lead) starts 1 5/8" down, and the entire bolt length is 2.5" (starting at the rock surface, the tapered end is just shy of 2.5" so I'm assuming the bottom of the sleeve - aka minimum hole depth - has to be 2.5" or so). When I placed an identical stud bolt in one of the holes of the anchor of Grenade Launcher, the bolt hit the sleeve with maybe 1/4" of threads sticking out above the nut, so when tightening it's a really minimal margin of error for the sleeve to engage.  Side note - stud/wedge bolts length is the overall length of the bolt, and 5-piece length is measured below the washer, which is why you drill a lot deeper for a 2.25" 5-piece! |
