Dewalt Powerstuds

timothy fisherwrote:

So there is a thing called fatigue. We use bolts with safety factor to reduce loss of strength due to fatigue....

hmmmm, yeah, that's not really how it works.

You trying to tell me that you dont want a fastener that may see multiple thousands of loads over it's life to be way stronger than the max load it will see?

Trying to understand what you mean?

timothy fisherwrote:

You trying to tell me that you dont want a fastener that may see multiple thousands of loads over it's life to be way stronger than the max load it will see?

Trying to understand what you mean?

It already is way stronger than the max load it will see?

timothy fisherwrote:

You trying to tell me that you dont want a fastener that may see multiple thousands of loads over it's life to be way stronger than the max load it will see?

Trying to understand what you mean?

"We" don't use bolts with safety factor to reduce loss of strength due to fatigue. It has nothing to do with fatigue.  A climbing bolt isn't going to log enough falls to where we are going to care about fatigue.

timothy fisherwrote:

You trying to tell me that you dont want a fastener that may see multiple thousands of loads over it's life to be way stronger than the max load it will see?

Trying to understand what you mean?

Typical fatigue loading cycles are in the millions if not 10 of millions.
We have a safety factor basically built in at about 3:1 for strength.
Cyclic loading is far down on the list of things to worry about. Rock quality and type of steel for a given environment is bigger worry.

Point me to the failed bolts due to cyclic loading on machined threads in the climbing sphere.

So what I’m hearing is no bolt is safe! I’m going back to pitons and installing rebar ladders up local classics.  Be nice to each other!

timothy fisherwrote:

So there is a thing called fatigue. We use bolts with safety factor to reduce loss of strength due to fatigue. The best rolled thread 3/8 wedge bolts have enough safety factor in hard rock to last an indefinite amount of time. 

In my opinion that should be our goal. We should not be looking for the cheapest wedges we can find. 

2 years means nothing! 

If you are using  3/8 stainless Confast wedges as a permant anchor  point you need to rethink what you are doing.  

I am actively rethinking what I am doing... by having this discussion on a public forum.  I will change my ways when someone gives me solid evidence that what I am doing is wrong.  You are most definitely not that guy though! If anything your opinions and reasoning only serve to reaffirm what I am doing. 

2 years?  The next time I'm back out there I'll take a picture of a perfectly fine, rustless, plated steel, wedge anchor I placed in 1993.  

Derek Woodswrote:

How does one know this? Is there something about the process of machining that makes it more likely to be used for cheaper bolts?

Whether a manufacturer rolls or machines the bolt may not be mentioned in their documents (so far as I have seen). 

I asked Simpson about the Wedge-Alls, and they report that <10" long are rolled. >10" are machined.

Can I help?

Metal fatigue is generally split into two categories, high cycle and low cycle. High cycle is where the loading is inside (roughly) the elastic limit of the material so unless you are worried about wind-induced vibration of no consequence (and yes, I've been asked about this and ran a test using a glue-in to fasten the head steady on a 400hp diesel generator at 1600 rpm, it lasted 70.000hrs before the engine was replaced). Low cycle is when the material is stressed past it's elastic limit. This doesn't really occur in bolts as the stress means they bend and usually take up a shape which no longer changes, the elastic limit for bolts is extremely low, 2 to 4kN is a reasonable number. I've naturally tested this as well with a 6mm rod glue-in and pulled it straight out at 25kN for 1.000 times then got bored and increased the load progressively until in the end the granite block actually failed (it fatigues as weĺl) at over 1.400 pulls and over 40kN. Fortunately (unlike normal steel stainless gets stronger the more you abuse it and you can achieve nearly double the nominal tensile strength in the end.

Machined threads can be woefully weak, I've seen under 10kN for 10mm bolts whereas a rolled thread will be around 38kN.

Machined threads are not only more likely to gall they are far more prone to SCC, that nobody reports failed bolts due to machined threads is because they don't look at them, the prevelance of certain brands of bolts that have failed leads to a certain amount of suspicion though.

25kN for European bolts is well founded and justified, some aspects of the standard are dubious but that strength requirement I fully agree with.

Kyran Keislingwrote:

2 years?  The next time I'm back out there I'll take a picture of a perfectly fine, rustless, plated steel, wedge anchor I placed in 1993.  

It really depends on the area.  I've got quite a few plated Rawl 5-piece bolts the were placed in granite in 1995 that look brand new and are tight as ever.   

I don't recommend it though and have switched to stainless steel.

Derek Woodswrote:

I asked Simpson about the Wedge-Alls, and they report that <10" long are rolled. >10" are machined.

Thanks for that, I was using their 5" bolts, so the galling I experienced must have just been from over torquing

I use the low strength (purple) thread locker on SS to prevent galling.  It seems to be weak enough that it will allow the nut to be tightened in the future without spinning the bolt.

Anybody else tried this?

Why are you guys having such an issue with galling?  In the 30 plus years of putting up new routes I can't think of a single instance of galling.   Whats happening that makes it occur? 

As far as SS bolts loosening I have been using the new Fixe hanger with the raised area around the hole, so far I haven't had to re tighten any bolts but time will tell.   Ive only had to re tighten a hand full of SS bolts over the years any way so it hasn't been a issue of huge concern.

Oh, are the threads on 5 piece  either 1/2 or 3/8" bolts rolled or machined?  I stopped using 3/8" five piece a few years back when the head snapped off while tightening it and it wasn't even at the recommended torque.  It made me wonder how many bolts are out there that are cranked down just under failure and are time bombs.  In hard granite I switched to SS 3/8 wedge bolts or 1/2" 5 piece but I lost all trust in 3/8" five piece after that.

timothy fisherwrote:

There are some good Youtube vids out there. 

Vid of the basics for reference^

Love the bolt mechanics being discussed, though, I agree that rock quality/placement and type of steel for a given environment is often a bigger/more common concern.

Kevin Mokracekwrote:

Why are you guys having such an issue with galling?  In the 30 plus years of putting up new routes I can't think of a single instance of galling.   Whats happening that makes it occur? 

I've just always used low strength thread locker to lightly lubricate SS threads to insure that I'm getting the maximum specified torque.  Friction between the nut and bolt can create a false reading.  I started the practice because local folks where having galling issues when everybody was switching to SS. They initially tried a drop of oil but that was resulting in loose nuts.  Low strength thread locker seemed to prevent galling, prevent loose nuts, and still be tightenable down the road.   Maybe they were using cheap machined thread bolts?    Maybe it's not necessary with good hardware.  I've been using Hilti KB-TZ  for the last few years and have just continued the practice out of habit.  

Adam Pequettewrote:

I've just always used low strength thread locker to lightly lubricate SS threads to insure that I'm getting the maximum specified torque.  Friction between the nut and bolt can create a false reading. ...

Most torque specs are provided with the assumption of "dry torque" (non-lubricated nuts and bolts). There are charts to show the percentage to decrease the torque, according to various lubricants. Each type of lubricant will have a "wet torque" value. Lubricating the threads and then torquing to the dry spec results in over-torquing the fastener.

"The Loctite people recommend reducing applied torque by 20 percent from dry values when using their liquid thread-locking compounds on threaded fasteners."

 source:   cycleworld.com/2014/07/25/a…

Thank you Jim Titt.

Also for F1 insight....Some of us are paying attention.

Adam - When I got back into developing a few years back I was doing it the same way I had always done it but when I started looking into the information here on MP I discovered the value/longevity of SS. Intelligent people convinced me to change.  Even though my PS anchors were fine from 25 years earlier I started spending more money because I was convinced that ultimately they will last longer.  Way longer than I will be climbing that's for sure.  

Jim Titt - Sorry I am new to all of this and I have a ton of questions. 

1. What is SCC?

2. In the video I saw them pulling machined threaded bolts out of granite and they were all way beyond 25kn.  The fact that you have seen 10kn, is that just 1 out of many bolts? Or were you breaking every bolt in the box at 10kn?  Is it just a once in a while defect or something? 

2. Are you saying that when a machined threaded bolt fails (I am assuming you mean sheers when you say fails) that folks aren't looking at the threads?  A bolt failing is a pretty big deal and it seems like the bolt would be studied at length regarding every aspect.  That is how it was determined that SS should be used in ocean proximity and high precipitation areas, because they were failing and people started studying the cause. I also am assuming you are referring to a machine bolt that failed in use in a rock climbing scenario correct?

3.  Why is 25kn the standard for single pitch routes? I am assuming that 25kn is above the force that a factor 2 fall would produce.  I could see it as a standard for multipitch routes but is it even possible to produce a factor 2 fall on a single pitch route? 

4. Lastly - Since there isn't anyone who has recommend a good rolled thread product that is comparable in price to the Confast bolts I started looking more in depth. I see that on the Team Tough website that your bolts are very affordable.  Are these bolts what you would recommend that I use in the future? https://www.team-tough.com/cart   If so, I will most certainly switch to these for next season.  

I'm sorry to be a bother but I think it is important to have this stuff out there so that myself and others can make proper educated decisions about how to utilize our natural resources in the future and you are an authority on this topic.