Chains as TR anchors: a problem?

Rmsyll wrote:'bearbreeder' commanded 'lets not have massive amounts of posts on TR anchor analysis on bolts" If the subject does not interest you, it is appropriate for you to stay out of it. .

who ever knew that TR anchors on 2 bolts could be so complicated ...

the only people i know who run around spouting stuff about TR bolted anchors are new TR tough guys that want to show off their "knowledge" ;)

Got that right.

I like locking ovals on a top rope anchors. Won't pinch the rope.

kennoyce wrote: The bolt spacing is probably fine. Those look like they're probably about 6 inches apart and there is one powerbolt (5-piece) and one wedge anchor. Both the powerbolt and the wedge anchor have a minimum spacing of 2 x the length of the bolt to achieve full strength and they are most likely 2.25" to 3" in length.

I think that the spacing is closer to 4". I should know, I see 4" every morning (but my wife thinks thats what 8" looks like, ka-pow!!!). We have an arbitrary standard out of nowhere of trying to get 8" spreads.

why not just stick the rope directly through the chains like a lot of gyms do?

Mike Lane wrote: I think that the spacing is closer to 4".... We have an arbitrary standard out of nowhere of trying to get 8" spreads.

From Jim Titt (who knows what he's talking about)

"Bolt depth and spacing:-
In Europe the wedge (or through) bolt are the universal bolt and these comments ONLY cover this type of bolt. There has been virtually no testing here on the 5 piece type.

There has been some controversy about the recommended depth, with the UIAA trying to push through 7cm/7 X diameter but this has failed as the manufacturers of the bolts temselves are adamant that 5 X the diameter is adequate. This is the requirement of the European Technical Approval to which they are tested by the manufacturer, the bolts are then bought in by climbing equipment manufacturers and tested to EN959 for resale. 5 X dia (that is 50mm embedded depth for the standard 10mm bolt used here) has proved time and again to be adequate. To allow for the nut, hanger, a bit of pull out when tightening etc the usual choice is an 8cm bolt, the next shorter commercially available bolt is 6cm which is cutting things a bit fine though on the hard granite these are sometimes used to save drilling.

The spacing recommendations are generally extremely conservative as they are based on concrete tests which work out a bit different from solid rock.
However to conform to the bolt manufacturers own certification we (and everybody else) just say 200mm to save a lot of confusion. Personally I generally place at a minimum of 230mm because that is how far it is from the tip of my thumb to little finger. As mentioned, further apart reduces the chance of hitting a fault in the rock."

200mm = 7.87 in So while probably overkill, I too try and get a hand width of spacing for my anchors in nearly every type of rock. you can probably go less in Granite and other bomber, non-fault prone rock types but if it's not an issue (as with these long chains) why not go for 8in?

mattm wrote: From Jim Titt (who knows what he's talking about) "Bolt depth and spacing:- In Europe the wedge (or through) bolt are the universal bolt and these comments ONLY cover this type of bolt. There has been virtually no testing here on the 5 piece type. There has been some controversy about the recommended depth, with the UIAA trying to push through 7cm/7 X diameter but this has failed as the manufacturers of the bolts temselves are adamant that 5 X the diameter is adequate. This is the requirement of the European Technical Approval to which they are tested by the manufacturer, the bolts are then bought in by climbing equipment manufacturers and tested to EN959 for resale. 5 X dia (that is 50mm embedded depth for the standard 10mm bolt used here) has proved time and again to be adequate. To allow for the nut, hanger, a bit of pull out when tightening etc the usual choice is an 8cm bolt, the next shorter commercially available bolt is 6cm which is cutting things a bit fine though on the hard granite these are sometimes used to save drilling. The spacing recommendations are generally extremely conservative as they are based on concrete tests which work out a bit different from solid rock. However to conform to the bolt manufacturers own certification we (and everybody else) just say 200mm to save a lot of confusion. Personally I generally place at a minimum of 230mm because that is how far it is from the tip of my thumb to little finger. As mentioned, further apart reduces the chance of hitting a fault in the rock." 200mm = 7.87 in So while probably overkill, I too try and get a hand width of spacing for my anchors in nearly every type of rock. you can probably go less in Granite and other bomber, non-fault prone rock types but if it's not an issue (as with these long chains) why not go for 8in?

From Powers Fasteners (who know what they're talking about since they make the bolts)

For the power stud (wedge bolt)
"Critical Spacing is equal to 2 embedment depths at which the anchor achieves 100% of load"

For the powerbolt (5-piece)
"For anchors loaded in tension and shear, the critical spacing is equal to 2 embedment depths at which the anchor achieves 100% of load"

Now, I'm certainly not saying that you shouldn't place your bolts further apart, it's always good to be conservative, but just judging from the photo the spacing on these bolts is probably fine.

mattm wrote: So while probably overkill, I too try and get a hand width of spacing for my anchors in nearly every type of rock. you can probably go less in Granite and other bomber, non-fault prone rock types but if it's not an issue (as with these long chains) why not go for 8in?

These chains are in some of the hardest quartzite there is. It is much harder than granite. That particular set of anchors and the ones near them drained a battery with only 3-4 bolts placed and pretty much dulled a bit getting them in. I was told by the person that placed them that he gets ~1/4 of the number of holes in this rock as compared to drilling in granite (for a given battery charge) and that he usually requires a fresh bit every time he starts a new project. Pilot is an interesting place. There is a lot of choss, but where the rock is solid and has no faults, it is bullet-proof.

csproul wrote: These chains are in some of the hardest quartzite there is. It is much harder than granite. That particular set of anchors and the ones near them drained a battery with only 3-4 bolts placed and pretty much dulled a bit getting them in. I was told by the person that placed them that he gets ~1/4 of the number of holes in this rock as compared to drilling in granite (for a given battery charge) and that he usually requires a fresh bit every time he starts a new project. Pilot is an interesting place. There is a lot of choss, but where the rock is solid and has no faults, it is bullet-proof.

wow, knowing that I'd say that anchor is good to go! Quartzite is crazy hard rock. At the gunks I would trust TINY nuts more so than anywhere else since I'd probably have to blow the cables to have a placement fail.

Those chains are pretty shiny, I would hate to catch a glare and blow the final move. Also were those nuts individually tested with a touque wrench to manufactures specifications. Just checking.

yer... yer... yer....... GUNNAAAAA DIEEEEEEEEEEEE!!!!!!!

touque wrench, what the hell is that.

Nice link!

mitchy wrote:touque wrench, what the hell is that[?]

It's a Canadian thing.

superkick wrote:why not just stick the rope directly through the chains like a lot of gyms do?

Im fairly certain you should know the answer to your own question, considering you possess the "knowledge" to argue over the use and practicality of screamers.

What type of chain is the best to use for such anchors? After looking at some chain at the hardware store, it seems like 3/8" zinc-plated (2600 lb working load limit) would be more than sufficient, and has big enough links to fit almost any biner through them, and sustain a bit of wear from pulling ropes, etc.

superkick wrote:why not just stick the rope directly through the chains like a lot of gyms do?

Seriously?

See picture #2

Second Example

Tope Rope Etiquette

Agree with majority on this one... set up looks ok. I Don't usually trust the last link in chains (as people top rope directly off of them... see above) so I clip one up. You just have to be careful the last chain link doesn't get in the way or cause any problems (i.e. the rope running over it, etc.) Using lockers will help mitigate this risk. In this case-it looks pretty good though.

Yer not gonna die.

I rapped down to a mid route rap station (chains) in the Gunks the other week only to find a group toproping directly through the quick links. That arrangement was annoying because 1) toproping through the quicklinks wears them down faster - use your own draws for that, and 2) we had to wait on the friggin ledge for them to finish their little toprope party before we could rap the bottom pitch.

Not treadjacking, just venting.

Emmett Lyman wrote:I rapped down to a mid route rap station (chains) in the Gunks the other week only to find a group toproping directly through the quick links. That arrangement was annoying because 1) toproping through the quicklinks wears them down faster - use your own draws for that, and 2) we had to wait on the friggin ledge for them to finish their little toprope party before we could rap the bottom pitch. Not treadjacking, just venting.

Closest I've ever come to blows at the Gunks was coming down to the rap station at the top of Jackie and finding the same setup. Except this time it was some asshole of a guide that was letting his client toprope through the chains. And then he was pissed off at us for wanting to use the rap station! Instead of lowering his client and pulling the rope, he just let his client keep on climbing.

At which point we threaded our rope on top of his (pinching it in place), and rapped. He was pretty pissed, but really couldn't do anything but keep belaying his client who was stuck in place until we had finished rapping.

Have to say the other times this has happened to me the topropers just didn't really know what they were doing, and were happy to either let us rap on their rope or to pull their rope. This time it was just an asshole who happened to think that being a guide meant he gets to treat the cliff like his property.

superkick wrote:why not just stick the rope directly through the chains like a lot of gyms do?

Yeah I gotta jump on this one too. You've got to be kidding or trolling when you say that.

Your stats claim you can climb 5.11 so it must be a troll.