Single Leg Glue Ins

Thought I'd start a new topic on single leg glue ins.  There's a fair amount of discussion and info out there on the Bühler style "P" bolts in their various offerings (Jim's twists, Waves, AustriAlpin, Climbing Technology, Titan Ti etc etc) but I simply haven't read as much on single shaft products (at least on English sites).  BP makes their grooved ones, Raumer has several offerings, Fixe has a few as does Petzl etc.

The big advantage I see with the SLB is you get a much larger stock diameter for the hole size.  This COULD be advantageous for super low profile anchors and lower offs in low use areas or as crux bolts where bailing might be helpful.  I can also see their use where you're trying to use the same hole but not re-drill it (eg pulling an old 3/8" and using an 8mm SLB or putting a 10mm SLB in a 1/2" hole - obviously a 6mm twist would go in to so a bit less debate there).

Some questions come to mind.  
1) with the smaller shaft, glue bond strength becomes important.  Should one use epoxy only (HIT 500 or Liquid Roc 500 etc) or are the acrylics ok?  
2) What concerns are there with rotation?  Some such as Jims seem to have a good mechanical interference while others are fairly light (Raumer Superstar is more a texture, others are more just rings on shaft).  Does the angled shaft end really work?  What about the texture ala Raumer?  
3) how often are these being installed with a counter sunk groove? I worry about "clickies".

Other thoughts?  

 

10mm Stock SLBs (Petzl, Raumer, Raumer Superstar)  Should one countersink them?


BPs various diameters with a 6mm twist for ref.


SLBs  in French lower off style - interesting ultra low profile setup. Would belaying off the lower one in a MP situation cause twisting issues?

 
Would something like this (12mm top SLB) be better?

With the exception of Jim Titt, I would not expect any "expertise" here on MP on this subject.  Besides, we are all in forced isolation, so are prone to lashing out.

You need to read the original manufacturer's instructions for each bolt type regarding whether they must be countersunk.  I think they all require countersinking.  FYI, countersinking is a major PITA.

Also, read the original manufacturer's instructions regarding the acceptable type of installation glue.

Just listened to The All Things Climbing podcast called Fixing Dangerous Bolts where they interview Greg Barnes.  He touches on glue ins.  I bet if you even reached out directly to him he could answer your questions with much less risk than trusting answers here.

Hey Matt, we have tested a bunch of single leg Bolts so far. Feel free to wade thru the chart. 
Off the top of my head, without reviewing all the tests I am not concerned by any of those questions re single leg bolts in the force range climbers can put on bolts.  
Bolt busters Raw Data

mattm wrote
 

SLBs  in French lower off style - interesting ultra low profile setup. Would belaying off the lower one in a MP situation cause twisting issues?

 
Would something like this (12mm top SLB) be better?

Being that your a hole for hole purist.  How do you plan to replace these when they are worn?  The glue and non rope wearing points should last a very long time.

mattm wrote: Thought I'd start a new topic on single leg glue ins.  There's a fair amount of discussion and info out there on the Bühler style "P" bolts in their various offerings (Jim's twists, Waves, AustriAlpin, Climbing Technology, Titan Ti etc etc) but I simply haven't read as much on single shaft products (at least on English sites).  BP makes their grooved ones, Raumer has several offerings, Fixe has a few as does Petzl etc.

The big advantage I see with the SLB is you get a much larger stock diameter for the hole size.  This COULD be advantageous for super low profile anchors and lower offs in low use areas or as crux bolts where bailing might be helpful.  I can also see their use where you're trying to use the same hole but not re-drill it (eg pulling an old 3/8" and using an 8mm SLB or putting a 10mm SLB in a 1/2" hole - obviously a 6mm twist would go in to so a bit less debate there).

Some questions come to mind.  
1) with the smaller shaft, glue bond strength becomes important.  Should one use epoxy only (HIT 500 or Liquid Roc 500 etc) or are the acrylics ok?  
2) What concerns are there with rotation?  Some such as Jims seem to have a good mechanical interference while others are fairly light (Raumer Superstar is more a texture, others are more just rings on shaft).  Does the angled shaft end really work?  What about the texture ala Raumer?  
3) how often are these being installed with a counter sunk groove? I worry about "clickies".

Other thoughts?  

 

10mm Stock SLBs (Petzl, Raumer, Raumer Superstar)  Should one countersink them?

BPs various diameters with a 6mm twist for ref.

SLBs  in French lower off style - interesting ultra low profile setup. Would belaying off the lower one in a MP situation cause twisting issues?

 
Would something like this (12mm top SLB) be better?

The bond strength is unimportant, we consider it to be zero and so does the standard (and the fact you can get clickies shows this is correct, they normally occur when the differential expansion of the bolt and rock causes the resin bond to the shaft to fail). The thing that matters is the shear strength of the resin and the area that is put in shear (the grooves or notches), the only company I can think of that specifies epoxy is Titan climbing. 

The knurling on the Raumer bolts actually gives a large surface area in shear, they get 514mm² which is good enough even with polyester to get the 25kN pull out. The same length (80mm) bolt from me has a shear area of 1103mm², spirals are good!

The 45° end cut is plenty for most designs, rotation is something that some worry about, others don´t! As long as the things don´t come out realistically it´s irrelevant. There is a torque test for the UIAA Safety Label but it´s fairly uninteresting, EN959 doesn´t bother with it.

The only bolts that need notching are the classic Fixe and one of the Raumer designs, both because un-notched they leave a Vee between the top of the bolt and the rock which can trap the rope. Titan Climbing reportedly say notch theirs but I´ve no idea why.

Thanks as always Jim. Your posts are the “Nova” of MtnProj.  

I like SLB for crux bolts. Would use them when replacing bolts that normally had permas on them if I was using glue ins.

I think an easilly replaceable wear point on bolted anchors should be a standard. SLBs may be easier to get out than other glue ins but most will just get cut and patched. Being a hole reuse purist :-)

Timothy Fisher wrote: I like SLB for crux bolts. Would use them when replacing bolts that normally had permas on them if I was using glue ins.

I think an easilly replaceable wear point on bolted anchors should be a standard. SLBs may be easier to get out than other glue ins but most will just get cut and patched. Being a hole reuse purist :-)

The replaceable wear point is usually a goal of mine as well.  In the possible implementation I'm looking at, wear issues are really, really low.  The old Metolius Rap hangers put in place in the early 90s show little sign of rope wear, even after 25+ years. (They were used for their low visual profile).  They're now corroded and the mech bolts looking sad so considering large SLBs.  My thought process was a 10 or 12mm round stock will wear equally as well and if a groove did become a concern one can always add a ring w/QL [as has been done at other anchors].  If something really odd did occur and the glue in was shot, adding a new one directly on top is an option - Then one could choose a thinner gauge and use a QL and ring.  I'm not a purist either; I usually adapt the best option to the task at hand.   

I don't think the bolt itself should ever be a rope bearing component. We should be trying to make sure our installs last as long as possible, and that completely defeats the purpose. One can not predict the popularity of a route 20-50 years from now. I also don't buy the visual argument, as I can camo a single leg bolt as well as a quick link ring set up. Not putting a quick link and ring/hook on the top bolt is just cheap.

Jim Titt wrote:

The bond strength is unimportant, we consider it to be zero and so does the standard (and the fact you can get clickies shows this is correct, they normally occur when the differential expansion of the bolt and rock causes the resin bond to the shaft to fail). The thing that matters is the shear strength of the resin and the area that is put in shear (the grooves or notches), the only company I can think of that specifies epoxy is Titan climbing. 

The knurling on the Raumer bolts actually gives a large surface area in shear, they get 514mm² which is good enough even with polyester to get the 25kN pull out. The same length (80mm) bolt from me has a shear area of 1103mm², spirals are good!

The 45° end cut is plenty for most designs, rotation is something that some worry about, others don´t! As long as the things don´t come out realistically it´s irrelevant. There is a torque test for the UIAA Safety Label but it´s fairly uninteresting, EN959 doesn´t bother with it.

No argument with anything Jim says here.  I just wanted to say that I've placed hundreds of single-leg Ti Tortuga bolts.  Many of them with the old Hilti C-100, the rest with Hilti RE-500.   It's been twenty years and we've had no bolt failures at all.

But, I did want to relate some information.  Originally we used C-100 which did NOT bond to the Ti (possibly why Titan suggests epoxy).   With a single leg and no major "flats" on the shaft (added later), some of the bolts would rotate slightly in the hole (~1-2 degrees) and this would freak out people.   So I did some tests where I used a crowbar to rotate the bolts in the hole, over and over, until I could spin them with my finger.  Then I tried to pull them out.  The eye broke without any movement in the shaft.

i don't have a photo of those particular bolts, but here's a representative one of the Tortuga so you can see the shaft design.

The only bolts that need notching are the classic Fixe and one of the Raumer designs, both because un-notched they leave a Vee between the top of the bolt and the rock which can trap the rope. Titan Climbing reportedly say notch theirs but I´ve no idea why.

Neither do I.  I've never bothered.  Martin told me a long time ago that notching made them stronger, which is pretty obvious, but they are plenty strong enough and easier to clip without it.

Hey gang, quick question (not engaged in bolting, just Ti-Curious), what is notching? Is that cutting a relief into the rock just below the hole to allow the glue in to recess a bit into the rock?

thanks

You got it.
I do it whenever installing the FIXE slbs cause that's what they recommend. It's not hard to do, makes them more resistant to twisting and looks better imho.

Joseph Gstoettenmayr and myself used a similarly designed single leg lower-off in Sicily for maybe hundreds of routes and after a few years started to get reports of some loose ones ("clickies") but the local who does the rebolting said either he couldn't find them or if he did couldn't get them out. So three of us went down to check it out and at 5 in the afternoon we found a loose one (not the reported one, the next door route). Went back at 9am and they were all rock solid again. So we checked the other four that had been reported and at 6pm after a full days Sicilian sun 3 were loose, at 9am they were all tight.

We cured the problem by running a drill down the side which grooved the bolt a bit then filling with resin.

Joseph is pretty creative (he teaches engineering at a trade school) and has bolted thousands of routes in Austria, one of his local crags people kept using the wrong lower-off for top roping which loaded it to the side and it kept coming loose so he made a glue-in inside a tube which was completely free to rotate, that freaked the guys out!

Taylor Spiegelberg wrote: I don't think the bolt itself should ever be a rope bearing component. We should be trying to make sure our installs last as long as possible, and that completely defeats the purpose. One can not predict the popularity of a route 20-50 years from now. I also don't buy the visual argument, as I can camo a single leg bolt as well as a quick link ring set up. Not putting a quick link and ring/hook on the top bolt is just cheap.

Irking the land manager with too many QLs and rings is a real risk.  We have them but the fewer there are the better.  I can, with a fair amount of intellectual honesty, tell you I CAN predict the popularity of the routes in question 20+ years for now.  Given they're mostly hard slab routes (10+ and up) that all fall into the R/X world I'm going to bet they'll remain extremely low milage for years to come.    Descent is also by rap, not lowering, so again, low mileage.  The existing rap hangers have minimal wear after 20+ years.    Not putting a QL and ring at the top COULD be cheap but it could also be a measured decision taking into account numerous local factors. It's not an A vs B thing.  It can be introduced as the lowest impact form and if wear does become a concern, you can always add rings later.  Nothing is lost. Yes, in general replaceable wear points are the ideal to strive for but one must also weight other considerations in the equation.    

For soft rock (tuft, soft sandstone, etc.) I much prefer using 1/2 threaded bolts. I don't have the study handy, but they outperformed the notched glue-ins by a large margin. For overhangs I go further and glue in U-bolts (also in the study).
Edit: The u-bolts were not 1/2. 5/16 is usually good. 

Trad Man wrote: For soft rock (tuft, soft sandstone, etc.) I much prefer using 1/2 threaded bolts. I don't have the study handy, but they outperformed the notched glue-ins by a large margin. For overhangs I go further and glue in U-bolts (also in the study).
Edit: The u-bolts were not 1/2. 5/16 is usually good. 

I would like to see that study if you come across it.  I switched to glue ins on soft rock because half inch powers bolts were breaking the rock crystals when tightening and not torquing properly.  Or do you mean glue in 1/2 inch threaded bolts/rod?

Trad Man wrote: For soft rock (tuft, soft sandstone, etc.) I much prefer using 1/2 threaded bolts. I don't have the study handy, but they outperformed the notched glue-ins by a large margin. For overhangs I go further and glue in U-bolts (also in the study).
Edit: The u-bolts were not 1/2. 5/16 is usually good. 

If you're referring to the the South African report circa 2000 then yes, threaded studs did well there.  It's worth noting how dated that report is however.  I know of no modern recommendations for U Bolts and in many cases, they're being replaced as needed with single hole variants.  Threaded bar stock is a kludge and expensive as you still have to provide a hanger and nut.  Any of the modern bolts available (Twist, Wave, Raumer, Fixe etc etc) will be more than adequate.  Fixe has a threaded shaft eye bolt that would meet your practices well.

climber pat wrote:

I would like to see that study if you come across it.  I switched to glue ins on soft rock because half inch powers bolts were breaking the rock crystals when tightening and not torquing properly.  Or do you mean glue in 1/2 inch threaded bolts/rod?

For soft rock I glue-in sections of 1/2 threaded rod

mattm wrote:

If you're referring to the the South African report circa 2000 then yes, threaded studs did well there.  It's worth noting how dated that report is however.  I know of no modern recommendations for U Bolts and in many cases, they're being replaced as needed with single hole variants.  Threaded bar stock is a kludge and expensive as you still have to provide a hanger and nut.  Any of the modern bolts available (Twist, Wave, Raumer, Fixe etc etc) will be more than adequate.  Fixe has a threaded shaft eye bolt that would meet your practices well.

Hangers and nuts are expensive? I got about 80 left over. Am I rich now?

Buy threaded stainless rod in 30' sections and cut them up with a chop saw and you'll actually save tons of money. 

Trad Man wrote:

Hangers and nuts are expensive? I got about 80 left over. Am I rich now?

Buy threaded stainless rod in 30' sections and cut them up with a chop saw and you'll actually save tons of money. 

SS Hanger ~$2-2.50  Nut 30-50c depending on 304 vs 316.   4" of rod?  304=44c/in   316= 81c/in  so  $1.76  or  $3.25.  So low end 304SS=$4.06         316SS = $5.75  

Quality manufactured 316 glue ins ~ $4 on the low end.  Not seeing the benefits ignoring shipping, labor. inferior hanger and the nut loosening negatives. You're getting a hell of a price on threaded SS if its worth it.

Jim has covered this twice before so I'll save him the typing -

Threaded rod is something of a half-way solution and has no real advantages and some big disadvantages.
First off it´s usually not cheaper as you have to buy the rod (and cut it) then buy a washer, nut and hanger + you need all the stuff to do glue-ins as well.
Second the quality of most threaded rod is appalling, from a 10mm rod you are lucky to see 8-9kN before it shears off. There is good threaded rod available but this isn´t cheap! 

As Francis mentioned creep can be an issue, the Australians has problems with this if I remember rightly. All resins creep to some extent when they are under continuous load and keeping a hanger tight takes a fair amount of force so the resin can start to release the bolt especially in high temperatures.
Since you have to go to all the effort of glueing the bolt in but you still end up with a hanger that can be stolen or come loose, will damage your karabiners and can´t be lowered from the whole idea seems a bit silly, probably why it isn´t popular!