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Powers SD4 stainless wedge


Original Post
YounginAyo · · Unknown Hometown · Joined Aug 2015 · Points: 20

Anyone know anything about it? The TDS seems pretty legit.

rocknice2 · · Montreal, QC · Joined Nov 2006 · Points: 3,129

12kn shear for the 3\8 stud. I wouldn't call that good at all. With the 1\2" you get 22kn. Weaker than some biners.

These are junk.

Ken Noyce · · Layton, UT · Joined Aug 2010 · Points: 2,415
rocknice2 wrote:12kn shear for the 3\8 stud. I wouldn't call that good at all. With the 1\2" you get 22kn. Weaker than some biners. These are junk.
Seriously, these are complete junk. 3/8" Hilti KB3 gets you something like 26 kN. UIAA requirements for a bolt are 20 kN in axial and 25 kN in shear so these are less than half the required shear strength.
rocknice2 · · Montreal, QC · Joined Nov 2006 · Points: 3,129

Shear doesn't get stronger with a greater depth. It's completely reliant on diameter and strength of material.

These studs are completely worthless junk for rock climbing applications.

Ken Noyce · · Layton, UT · Joined Aug 2010 · Points: 2,415

Just as an FYI, all the powers studs that I have seen have machined threads whereas most other bolt companies roll the threads on the bolt (even Rawl who was bought out by powers used to roll their threads). machined threads are inherently much weaker than rolled threads and as such, I wouldn't recommend any 3/8" powers stud bolt. Once you are in the 1/2" size the strength of machined threads is plenty for climbing applications, but in the 3/8" size, not so much.

Edit: I got my hands on a few of these SD4 bolts and they actually have rolled threads, so at least they have that going for them.  

slim · · Unknown Hometown · Joined Dec 2004 · Points: 1,107
ClimbBaja wrote:Shear doesn't get stronger with a greater depth. It's completely reliant on diameter and strength of material. Not true when describing characteristics of concrete fasteners. The variables of embedment depth and strength of concrete (psi)are shown on the specs charts. Perhaps this info should have been included in my last post: 2,745 lbs. is very low when compared to the 3/8" stainless steel wedge anchors of other manufacturers. For example: ITW Ramset/Redhead "Trubolt" : ranges from 2,320 lbs. to 4,500 lbs. ultimate shear Hilti "Kwik Bolt 3" : ranges from 3,300 lbs. to 5,954 lbs. ultimate shear Powers "Domestic Wedge Anchor" : ranges from 4,320 lbs. to 6,235 lbs. ultimate shear load capacity So, whey would 2,745 lbs. be consistent across the chart, when every other wedge anchor shows a range? It wouldn't be the first time that I have found Rawl/Powers charts to be inaccurate. Perhaps Powers will clear up this mystery with an e-mail response.
it varies across the chart because the limiting factor (whether it be the shear strength of the steel, anchor pullout/pryout, concrete breakout, etc) will be different, depending on the anchor depth, hole diameter, steel strength, and concrete strength.

like others have said, these aren't appropriate for climbing applications. honestly, i don't think i would use these for any application. they are pretty crappy in several ways...
Jim Titt · · Germany · Joined Nov 2009 · Points: 490
kennoyce wrote:Just as an FYI, all the powers studs that I have seen have machined threads whereas most other bolt companies roll the threads on the bolt (even Rawl who was bought out by powers used to roll their threads). machined threads are inherently much weaker than rolled threads and as such, I wouldn't recommend any 3/8" powers stud bolt. Once you are in the 1/2" size the strength of machined threads is plenty for climbing applications, but in the 3/8" size, not so much.
Yep, that´s about it. I´ve tested a fair number of different brands of 10mm stainless wedge bolts and the machined thread ones get roughly a third of the values of a rolled one when tested to EN959 (which gives considerably different results to the fastener industry test).
C. Williams · · the Climber Cave · Joined Jul 2013 · Points: 1,258

How do you tell if the threads were machined or rolled?

Ken Noyce · · Layton, UT · Joined Aug 2010 · Points: 2,415
C.Williams wrote:How do you tell if the threads were machined or rolled?
you just have to look at them, it's pretty obvious if you know what you're looking at, but not very easy to explain.
C. Williams · · the Climber Cave · Joined Jul 2013 · Points: 1,258
kennoyce wrote: you just have to look at them, it's pretty obvious if you know what you're looking at, but not very easy to explain.
Aw come on. Give it your best shot. What do you look for? I have Hilti KB3, Power studs, and Red Head Trubolt's and the threads look different on each brand. Any guide as to what method of manufacture each uses?
Ken Noyce · · Layton, UT · Joined Aug 2010 · Points: 2,415
C.Williams wrote: Aw come on. Give it your best shot. What do you look for? I have Hilti KB3, Power studs, and Red Head Trubolt's and the threads look different on each brand. Any guide as to what method of manufacture each uses?
Okay, I'll take a shot at it, Just for reference, KB3s are rolled, and power studs are machined (at least in stainless, I haven't ever purchased any in plated to know for sure), and I would guess that the Trubolt's are rolled, but it's not a brand I have purchased so I don't know. If you have stainless power studs available, take a look at the cone area and you will see very obvious tooling marks (look like lines going around the circumference of the cone). You wouldn't see these on a rolled thread bolt. You will also notice that the threads look very shiny compared to a bolt with rolled threads. Also, the threads will be much sharper, like you could almost cut your finger on them if you ran it across them, whereas rolled threads would be more dull. Hopefully this makes sense.
Matt Lisenby · · Unknown Hometown · Joined Sep 2008 · Points: 555

Here is a video regarding bolt thread manufacturing

rolled vs cut(machined) bolts

C. Williams · · the Climber Cave · Joined Jul 2013 · Points: 1,258

Good info, thanks for the clarification!

Brian in SLC · · Sandy, Utah · Joined Oct 2003 · Points: 15,692
kennoyce wrote: Okay, I'll take a shot at it, Just for reference, KB3s are rolled, and power studs are machined...
I did not know that. Hmm. Makes me like them KB3's even more!

Makes sense when I look at them.

Thanks.
C. Williams · · the Climber Cave · Joined Jul 2013 · Points: 1,258

I torqued a handful of these (3 SD4's and 2 SD6's) to failure this evening and they seemed solid. All snapped at around 60 ft-lbs on my torque wrench. Not sure how to convert that to axial force but it would be interesting to hear how that converts.

Ken Noyce · · Layton, UT · Joined Aug 2010 · Points: 2,415
C. Williams wrote:

I torqued a handful of these (3 SD4's and 2 SD6's) to failure this evening and they seemed solid. All snapped at around 60 ft-lbs on my torque wrench. Not sure how to convert that to axial force but it would be interesting to hear how that converts.

The general formula to calculate axial force from torque is F=T/(c*D) where F is the axial force, T is the torque, c is the coefficient of friction between the bolt and nut, and D is the diameter of the bolt, so if we assume that the coefficient of friction is .2  which is typical for steel (a pretty big assumption, I'm going to guess that the coefficient of friction is actually much higher) then the axial force would be (60 ft-lbs * 12 in/ft)/(.2 * .375 in) = 9600 lbs.   Even if the coefficient of friction was as high as .5 this would be an axial strength of 3840 lbs, and I want to say that I've seen  .4 given as a reasonable coefficient of friction for stainless on stainless, but don't quote me on that.   

Chris Wright · · Unknown Hometown · Joined Aug 2008 · Points: 460
Greg Barnes · · Unknown Hometown · Joined Apr 2006 · Points: 1,823

Junk, do NOT use for climbing.

The shear strength on the 3/8" Powerstud+ SD4 is only 2,745 lbs. Compare that to around 8,000 pounds for a 3/8" Power-bolt (5-piece), or 5,475 for a Hilti KB3.

Or just compare it to a 1/4" buttonhead bolt that's only 1 1/8" in the rock - 2,090 lbs.

Chris Wright · · Unknown Hometown · Joined Aug 2008 · Points: 460
Greg Barnes · · Unknown Hometown · Joined Apr 2006 · Points: 1,823

Oh...and the quote from me in the old thread is for the "Power-Stud" bolt, which is no longer made. I looked up the stated specs from an old PDF (2008) and the 3/8" Power-Stud bolt shear strength was listed as 3,760 - which is what I was talking about as far as being "weak side of acceptable."

People should pay close attention to the strength ratings on stud bolts, they vary widely even for bolts that at first glance look very similar.

Greg Barnes · · Unknown Hometown · Joined Apr 2006 · Points: 1,823

Wow! Those Hilti numbers are WAY different than their old numbers, earlier I just quickly grabbed an old PDF when looking up the 5,475 pound shear. Turns out that what I looked up was for carbon steel, the stainless steel one was listed as 7,005 lbs shear for 2 1/2" embedment, or 6,330 lbs for 1 5/8" embedment. The new number off their site (which you posted) is only 3,680 lbs shear. The old numbers were of "ultimate loads" and from a 2006 PDF. The new ones are "design strength" - I don't know if the newer bolts are weaker, or the design strength is much lower than ultimate load strength.

Guideline #1: Don't be a jerk.

Fixed Hardware: Bolts & Anchors
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