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Roger Brown
climber
Oceano, California
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Mar 23, 2015 - 06:49am PT
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There are a couple clues I look for on 3/8" wedge bolts, or any bolt that tightens down with a nut. The letter on the bolt will tell the length. Good bolts tighten down with just few turns. Too many threads on an "A"or "B" and you may only have 1/4" or so in good rock. I think the first 1/4-1/2" is probably damaged by the drilling, so I pull shallow bolts. Too many threads may also mean that the only reason the nut is tight is because it is bottomed out. A 3/8" threaded split-shaft I pulled last season was like that. I probably could have pulled it by simply stacking washers and re-tightening the nut back down. As it was, it slid right out with double tuning forks and spacers. (A 5/16" button head was replaced on the first rap of the R.A. in 2011. That is the 3/8" ASCA bolt/hanger on the left side of the anchor. It came out without much effort.)
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JimT
climber
Munich
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Mar 23, 2015 - 07:38am PT
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That makes me wonder about what type of stainless the common bolt hangers are made from. Shouldn't this be matched with the same type of stainless steel bolts, as well. What we need is a metallurgist to know how critical all of this might be given enough aging of the bolt/hanger system.
In the normal passive condition bolts are supplied in the potential between 301 and 316L is virtually zero, the two voltages mostly overlap in the galvanic tables. In stationary water which might be the case for us then you might see 100mV but itīs unlikely and also unlikely electrolytic corrosion takes place.
The European (and UIAA) standard requires all parts of the anchor to be made of the same material anyway so if you buy a certified anchor it is irrelevant, that said most of the bolts available actually use subtly different grades due to the way they are made even though they will be marked 316.
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two-shoes
Trad climber
Auberry, CA
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Mar 23, 2015 - 07:53am PT
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Jim T
What is your background of knowledge in this, may I ask, or what is your expertness? You sound credible, but how do you know this to be probably true, Please?
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bhilden
Trad climber
Mountain View, CA/Boulder, CO
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Mar 23, 2015 - 10:40am PT
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Bhilden,
That just means the maintenance and replacement intervals will be longer, not that they aren't needed. Good on you for doing the work.
Healyje,
I think it is more than that. Because of the wet environment in your area and your experience replacing bolts, it is pretty clear to me that any plated anchor, regardless of age, is suspect.
In dryer areas like we have at Pinnacles National Park, stainless steel is still the preferred metal for anchors, but the majority of the 5-piece plated steel anchors are good. Yes, there needs to be maintenance, but we have pulled 60-year old Star Dryins which looked just fine. Some of the 20-year old plated 5-pieces look almost brand new.
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two-shoes
Trad climber
Auberry, CA
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Mar 23, 2015 - 11:32am PT
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Clint,
Thanks for filling me in about Jim T.
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healyje
Trad climber
Portland, Oregon
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Mar 23, 2015 - 11:51am PT
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Bhilden - I think it is more than that. Because of the wet environment in your area and your experience replacing bolts, it is pretty clear to me that any plated anchor, regardless of age, is suspect.
In dryer areas like we have at Pinnacles National Park, stainless steel is still the preferred metal for anchors, but the majority of the 5-piece plated steel anchors are good. Yes, there needs to be maintenance, but we have pulled 60-year old Star Dryins which looked just fine. Some of the 20-year old plated 5-pieces look almost brand new.
I agree, wetter areas like ours really need to be on like a five or seven year maintenance sweep at minimum (or tackle a part of it every year and keep records on what you cover each year).
In really dry places I could easily see that out to a 15, 20 or even 25 year interval though I don't know in that case how the continuity of maintenance knowledge / records would happen.
Bummer when it comes down to bolts breaking for maintenance to happen but I think this idea of bolts requiring maintenance is really only recently sinking in to the larger demographic who, after 35 years of gyms, think all bolts are good and it must be someone else's job insuring that.
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JimT
climber
Munich
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Mar 23, 2015 - 11:51am PT
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JimT in your experience are most stainless hangers made from 316 or 301?
In my experience with obtaining stainless steel wedge bolts from suppliers like Concrete Fastening Systems http://www.confast.com/ is 301 is the most commonly available 'on the street' - just curious as to your opinion.
That site I referenced has great specs on shear and pullout strength in various grades of concrete, really interesting stuff.
301 is a sort of "poor mans" 304 as it lies effectively directly below 304 in the alloy mix but it has more carbon. 301 is cheaper (a bit) and better for deep drawing stuff like sinks and pots and pans so loads of stamping/pressing companies use it when they can instead of 304. The corrosion resistance is a bit worse but not a lot.
303 is a machining grade of 304 with suphur added, it suffers extremely badly from pitting corrosion, doesnīt like being bent sharply and has extremely poor weld strength. Some welded bolts were made of this in Austria which regrettably killed people. Itīs use was prohibited in the older version of EN959 and the UIAA standard.
Hangers are usually 304 at least in Europe and 316 are also available from AustriAlpin and Raumer for example. Incidentally 316 hangers are more expensive to make than the difference in material price would suggest, the tool wear is considerably faster with 316 and the press tools cost a lot of money. The press tool costs are nearly nearly the same as the material costs in the average hanger.
Wedge bolts seem no longer on the market in 304 in Europe, the building codes require 316 for most work so the manufacturers donīt bother with making two grades. I havenīt seen any on the market for some years now.
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two-shoes
Trad climber
Auberry, CA
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Mar 23, 2015 - 01:17pm PT
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Jim T.
Thank you for your knowledge, much appreciated.
Great question, too, Locker!
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Greg Barnes
climber
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Topic Author's Reply - Mar 23, 2015 - 01:18pm PT
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The stainless steel 5-piece (aka Power-Bolt) bolts are 304, they are not made in 316. To be highly specific, all components of these bolts are 304 except the expansion cone which is 303, and the washer which is 18-8 (you can find that info on page 3 of this PDF: http://www.powers.com/pdfs/mechanical/06914.pdf ).
Most stainless climbing hangers are 304. The exceptions are all Petzl hangers (and bolts), the "Marine grade" Fixe hangers, and Climbtech hangers (there may be more that are 316 but most are 304).
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Brian in SLC
Social climber
Salt Lake City, UT
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Mar 23, 2015 - 03:10pm PT
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I think some of Climbtech's hangers were made from a 400 series stainless steel. At least a gob of them I got are (so my magnet test says...ha ha).
I wouldn't think pairing them with a 300 series anchor bolt would be a bad thing especially in the interior of the west...
Thoughts?
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HighTraverse
Trad climber
Bay Area
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Mar 23, 2015 - 07:25pm PT
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This is telling (from JimT above)
in Europe, the building codes require 316 for most work so the manufacturers donīt bother with making two grades This is VERY informative. To me, this means we should only be using 316.
Brian in SLC
I think some of Climbtech's hangers were made from a 400 series stainless steel Yes, the magnet test is a quick way to eliminate the 300 series. However many modern high tensile strength SSTs other than 400 series are magnetic to varying degrees.
A 400 series stainless would be an odd choice for a bolt. The main use for the 400 series SSTs is where it has to be hardened. Think knives, industrial cutters/choppers, sometimes injection molds. Hardening any part of a bolt would be an unnecessary expense and might even reduce its longevity as 400 series ssts are much less corrosion resistant than nearly any other sst.
The "ideal" series stainless steels in my mind are the precipitation hardening series such as 17-4PH. These steels are specifically designed for high strength, hardenable, highly corrosion resistant applications.
These steels were originally created for submarine propellor shafts.
However, they are VERY expensive, in material cost and especially fabrication cost. They are the devil to cut and nearly impossible to form (as they harden with forming).
They can be hardened to just about any hardness up to their designed max so one could make bolts of optimum hardness and ductility. However, no one would be able to afford them.
We've used PH ssts a lot in very specific pharmaceutical manufacturing tools. Even in that very high cost industry PH ssts are only used when necessary. Especially for dry bearings (lubricants and your favorite inhaled drug don't go together!), fluid pumps etc, sometimes extrusion dies.
There's a machine shop owner in SoCal who's very likely going to prison for knowingly substituting some other SST than the specified sst for orthopedic implant screws. Guess what? They were weaker than required AND they stress cracked when micro cracks were initiated by "body juices". It's a helluva mess.
The FDA is also after the implant maker because they didn't adequately test their incoming screws.
D'OH!!
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JimT
climber
Munich
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Mar 24, 2015 - 01:06am PT
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300 series becomes magnetic when it is formed, all my 304 and 316 glue-in bolts are magnetic. The trace ferrite transforms in martensite when the material is bent. 2205 which we also use is magnetic anyway as itīs a duplex steel. Itīs a pain in the butt when I take my stuff to the morons at the scrap company.
17-4PH (1.4542 to us guys) wouldnīt be my choice, itīs a precipitation hardening martensitic and while it might be nice to be able to choose the hardness of the end product (though I canīt think why at the moment) itīs corrosion resistance is only the same as 304 at a high price.
8926 (1.4529) is the better material for considerably improved corrosion resistance at a vastly higher cost, wedge bolts are anyway commercially available in this material.Around $30 each.
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scooter
climber
fist clamp
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Mar 24, 2015 - 05:29am PT
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The last pitch straight up variation of Cryin' Time Again has 5/16 button heads.
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Dimes
Social climber
Retired from Everything
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Mar 25, 2015 - 08:38pm PT
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Here is another example from today that clearly demonstrates that you really do not know what is going on behind the hanger. Belay bolt from Echo Rock at Josh.
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Clint Cummins
Trad climber
SF Bay area, CA
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Mar 25, 2015 - 08:46pm PT
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Yeah, not one of the stronger bolt designs for that size hole.
At least you get a partial idea of the bolt design once you remove the hanger (but not observable to someone who is just clipping it).
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two-shoes
Trad climber
Auberry, CA
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Mar 25, 2015 - 09:18pm PT
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There is a route at Tollhouse Rock by the name of Brains, that has the type of bolt that Dimes is
exhibiting in those 2 photos, only it's not a 1/2" bolt, but a 3/8" bolt. Somebody thought they were
doing a good job by re-bolting the route with these. It had 1/4" button heads before.
What would you least trust?
This is on my to do list.
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Ed H
Trad climber
Santa Rosa, CA
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Mar 25, 2015 - 09:19pm PT
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We've had a few older 1/4 and 5/16 bolts fail, but no failures on the newer 3/8 five piece bolts - correct?
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Clint Cummins
Trad climber
SF Bay area, CA
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Mar 25, 2015 - 09:27pm PT
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I know people who have sheared the heads off of 3/8" 5 piece bolts when trying to install them. (Overtorquing).
There was also an accident at Pinnacles (Feed the Beast) where one of them unscrewed from the cone and pulled out. Solution was to glue the threads with Lock-tite. Then later glue-in bolts were installed.
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