Bolts - Use or Lose?

I'm planning on developing a cliff and I'm going to be placing anchors for TR. I'm thinking about using these because they're available to me for fairly cheap:
fastenal.com/web/products/d…
here is the performance spec from manufacturer:
itw-redhead.com/trubolt_per…

These will be placed in granite and even if I consider it 2000 PSI concerete these are still advertised at over 4,500lbs tensile and shear.

Edit to add that I'll be bringing along a torque wrench...

Yay or Nay?

Yay. The compressive strength of granite is going to be way higher than 2,000 psi. Depending on the rock quality, it will probably be higher than the 6,000 psi listed.

education.uncc.edu/cmste/su…'s%20Paper.doc

Each anchor would be over 36kn if that's the case. Is there a reason you're using 1/2" over 3/8"? I assume you're power drilling as opposed to hand drilling these. Just watch out for air pockets in the rock and don't over torque them.

Thanks for the response sqwirll. I couldn't get your link to work, but that's what I figured as well. I do plan on power drilling them but I'm not opposed to hand-drilling if it resorts to that. Just looking at the increased tensile and shear stepping up from the 3/8 to 1/2 size makes me go 1/2. I'd rather be overkill than killed and want these things to last a LONG time.

Edit: I went to the education.uncc.edu and ran a search for rock, minerals, jonathan and came up with the granite to concrete test. Good read, thanks!

sqwirll wrote:Yay. The compressive strength of granite is going to be way higher than 2,000 psi. Depending on the rock quality, it will probably be higher than the 6,000 psi listed. education.uncc.edu/cmste/su…'s%20Paper.doc Each anchor would be over 36kn if that's the case. Is there a reason you're using 1/2" over 3/8"? I assume you're power drilling as opposed to hand drilling these. Just watch out for air pockets in the rock and don't over torque them.

Is there somewhere to get a comparison or rating for different types of stone for compressive strength? I have been planning to do some bolting in Quartzite and have been concerned about the resulting strength. I tried the link you posted but it doesn't work. Thanks in advance.

Robert

Robert, look at my edit above. I had the same problem.

Not sure why that link isn't coming up right, but google granite psi and it's the first thing that comes up. 1/2" bolts would take forever to handrill fyi. I can get a 3/8"x 3" bolt installed in granite in about 35 minutes by hand. I wouldn't even consider hand drilling a 1/2" bolt. Have you found a good deal on stainless hangers as well?

craig512 wrote:Robert, look at my edit above. I had the same problem.

Thanks Craig, I saw that after I posted. I still haven't been able to find info for quartzite. I am looking to use the same type of bolt as you only in 3/8" dia. I see that it's tinsel strength in 4000psi concrete is 3850lbs so I believe it would be plenty strong. But like you I want to be safe.

Robert 560 wrote: Thanks Craig, I saw that after I posted. I still haven't been able to find info for quartzite. I am looking to use the same type of bolt as you only in 3/8" dia. I see that it's tinsel strength in 4000psi concrete is 3850lbs so I believe it would be plenty strong. But like you I want to be safe.

They get into it a little bit here under the section "A rock and a hard place".

safeclimbing.org/education/…

Looks like I found what I need......I love when I can answer my own questions. :)

Well, to be honest, I've never done either type of drilling and plan on practicing with a power drill and by hand on a pet rock first. No sense in drilling useless holes on a piece of precious stone! I might end up with the 3/8 anyway but will make sure the rock is bomber first.
In regards to hangers...no I don't have a good lead on them yet. My buddy has a machine shop though and we've contemplated home-made ones...if we could test them. LOL. But like I said before, overkill is the name of the game.

Looks like most Quartzite has a compressive strength of over 20,000 psi. Tho the actual range is 2000 to about 70,000 (at least according to the site I found).

So I guess my next question would be is 17-18kn strong enough for TR or belay anchors?

I think TR would be just fine, since they won't (edit: shouldn't) suffer a big shock load ever...but a multi-pitch anchor could potentially take a huge fall and people do dumb things, maybe someone climbs with a static rope and tries a Dan Osman maneuver?
I think going 1/2" is the safest bet for multi-pitch. It may take longer to drill and be a little more expensive, but I think those are the only downsides.

Robert 560 wrote:So I guess my next question would be is 17-18kn strong enough for TR or belay anchors?

That is per bolt, so when they anchor is properly equalized it's going to be signifantly higher than that. A 200 lb climber generates about 10kN of force during a factor 2 fall for reference.

I guess that puts it in perspective pretty well. I've just been looking at the numbers, and after taking another look, the numbers on the 3/8 should be high enough. I guess I'll debate with my buds about what they feel best about.

Let me jump in for a second -
Without costing too much more, the Kwickbolt from Hilti is far, far superior to Red Head. I'm a contractor, so I get special prices. A box of 50 3/8" x 3 1/2" runs me about $12.00. Set just one of each and you will notice the difference.

Better yet, for TR anchors use Powers 5 pc., if you can find them.

Is that $12 for 50 stainless bolts? If so, hook me up. Iprefer the Kwikbolts as well.

sqwirll wrote:Is that $12 for 50 stainless bolts? If so, hook me up. Iprefer the Kwikbolts as well.

Oh sorry, I missed the S/S detail. That price is for plated.

The Hilti Kwik Bolt II works great in rock types that have compression factors greater than the tensile strength of a given bolt. The Kwik Bolt is my bolt of choice for the varying granite we have in the Black Hills. Our LCO-BHCC used Hilti Kwik Bolts in our replacement program for a number of years. Now we have enough funding to purchase FIXE Triplex bolts.

Your quartzite's psi will generally excede the bolt strength. In light of this the Powers 5-Piece will be overkill at least considering the cost. 5-Piece bolts work great in suspect rock (chossy volcanics, sandstones, Limestones, etc...) due to the larger expansion zone/sleeve configuration.

One thought about using 5-Piece bolts is you are giving up the shear strength and tensile strength proportionate to the hole diameter. In effect the 1/2" 5-Piece bolts are being held near to the 3/8" bolt shear and tensile strength. This is limited by the actual 3/8" bolt that constitutes the shank within the 1/2" sleeve. In the end why drill a 1/2" hole for a bolt that is slightly stronger than a 3/8" bolt?

The Triplex is similar in construction to the 5-Piece and both are quirky at times due to becoming spinners before you ever set them. They are both removeable with a little effort. Using a 1/2" bolt makes sense when recycling a 3/8" hole during a replacement project. If a bolt is removeable the hole can be recycled for use as a glue in when the need arises for future replacement.

If the rock you are drilling in is bomber then consider starting with a SS 3/8" x 3-3/4" Kwik Bolt. Hilti is the only constuction grade bolt that holds itself to a true higher standard. IMHO Hilti bolts are well worth the extra money spent vs the cost of Red Heads.

One possible way to search for more info and get a better understanding is to look for info pertaining to "Mohs Scale of Hardness". Steel comes out being weaker than most rock at the end of the day.

Actually Brent, the very commonly repeated error that a 5-piece bolt is weaker than a stud bolt because the bolt core is 5/16" is just plain wrong.

Go check out the strength ratings - 3/8" 5-piece bolts are STRONGER than 3/8" stud bolts. Don't forget that the threads on a stud bolt reduce the actual diameter significantly. Also, the nut/thread/hanger interface is much more subject to work fatigue and loosening.

I can't tell you how many people repeat this error. Almost as many as think that plated bolts are stainless (you wouldn't believe how many people think that all bolts are stainless).

Stud bolts of any sort can't be removed in the future. At least everyone here is talking about stainless steel stud bolts - which are probably going to last a very long time, especially in arid areas. Especially with 1/2" stainless as the original poster is planning on using. The ASCA no longer uses any stud bolts - only 5-piece (Power-Bolts) and Fixe Triplex - simply because both of those can be removed for future replacement.

Greg Barnes wrote: The ASCA no longer uses any stud bolts - only 5-piece (Power-Bolts) and Fixe Triplex - simply because both of those can be removed for future replacement.

I think most climbers would like to use these, but at $10 for a bolt/hanger it's hard to swallow.

sqwirll wrote: I think most climbers would like to use these, but at $10 for a bolt/hanger it's hard to swallow.

If you are putting up a quality line that will hopefully be enjoyed for generations does it really make a difference if it costs you $150 for quality hardware that can easily be replaced vs $30 for cheap hardware?