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Tom
Big Wall climber
San Luis Obispo CA
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Jun 29, 2017 - 11:03am PT
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Bottom line: does it (a 9-inch cam) need to be stronger than 12kn?
If a 12kN rating was obtained from a pull-test using a steel frame with parallel walls, then the answer might be "yes". That 12kN number is artificially high, compared to what the cam can support when actually used in a a real crack. If a climber is expecting a cam to support 12kN on a rock climb, then the tested rating would have to be higher. Big cams are not like small cams. Their structural behavior in real life is quite different from that observed during a laboratory test.
When placed in a parallel-walled testing frame, the width of the cam lobes stabilizes them against sideways rocking and rotation. This will delay the onset of lateral deflection and bending of the cam lobes. The wider the cam lobes are, the more they will self-stabilize themselves in a testing frame.
To put it another way, a testing frame will not subject a climbing cam to the multi-axis loading that a real crack would. In a real crack, the cam lobes are subjected to out-of-plane loads that immediately deflect and bend the lobes sideways. Under high loading, the cam lobes are bent and deformed sideways. The out-of-plane loading and the bending forces rapidly increase in a non-linear fashion as the cam lobes bend and deform. If the cam lobes are wobbly on their axles (e.g. Camalots) the initial bending forces on the lobes are even higher.
Also, if the testing frame is not wide enough (along the direction of the axles) it will constrain the lobes from bending and deflecting laterally. This will also artificially increase the load that the cam can support.
And, if the testing frame is not wide enough to allow the cam to be almost fully open when tested, the results will be artificially inflated, compared to what could be expected of the cam during actual use.
In short, a pull-test of a big cam in a testing frame does not have good similitude to a big cam in a real crack. A "12kN" cam might only support 75% of that, or less, in the real world. If the cam lobes have been specifically designed to withstand high bending forces, the difference will be small. If cam lobes have big voids and thin sections where the bending forces are highest, the difference might be quite large.
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Matt's
climber
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Jun 29, 2017 - 11:35am PT
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If a 12kN rating was obtained from a pull-test using a steel frame with parallel walls, then the answer might be "yes". That 12kN number is artificially high, compared to what the cam can support when actually used in a a real crack. If a climber is expecting a cam to support 12kN on a rock climb, then the tested rating would have to be higher. Big cams are not like small cams. Their structural behavior in real life is quite different from that observed during a laboratory test.
Tom-- honest question-- how many times do you think all your valley giants have been subject to real climbing falls?
As others have alluded to, big cams are often used as pusher pieces-- I wouldn't be surprised that, in the decades of valley giants being in existence, the total number of actual falls that VGs have experienced is actually pretty low-- in essence, I'm not sure that you, (or any artisanal big cam manufacturer for that matter), have good real-world data supporting the view that their design can avoid deformation issues.
best,
matt
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Matt's
climber
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Jun 29, 2017 - 11:36am PT
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matt now that i know you have one of these in addition to your full rack of totems maybe i should ditch the lady friend and go to the needles with you after all...
You bailing on me for your new girlfriend definitely screwed up my weekend plans.... I thought I was going on a 4-day climbing trip, instead I'm going to work... :(
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Mei
Trad climber
mxi2000.net
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Jun 29, 2017 - 11:41am PT
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Strength vs. weight:
24kn tested, 17kn rated, 880g, VG9
12kn tested, __kn rated, 568g, Merlin #8
Should width -- distance between outer lobes -- be included in the comparison as well? It can be an indicator of stability for large cams like this.
Yesterday, I played with a Merlin #8 (not mine, but wish it were mine). Pretty slick indeed. My short fingers barely reach the trigger with the thrum in the loop, but I understand that my hand size is smaller than the average of those that would touch such a cam. I'll accept that.
Seeing its narrow profile and rigid stem, I'll not want to take a leader fall from above the cam. But on the other hand, I never want to take a leader fall from above any cam.
Sasah above looks like a natural OW climber.
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Tom
Big Wall climber
San Luis Obispo CA
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Jun 29, 2017 - 12:41pm PT
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Tom-- honest question-- how many times do you think all your valley giants have been subject to real climbing falls?
That is somewhat like asking how many times the air bag in my car has gone off. It's there in case it is needed, not because it gets used that way on a regular basis.
Climbing gear, especially big wall gear, shouldn't be designed for the lowest possible, or lowest acceptable loading. Unexpected things can occur on a rock climb, and if your gear is lacy and delicate, it might not be up to the task of a forced retreat, bivy or rescue. You may not be planning on whipping onto a pusher-piece, but what happens if you do?
My design philosophy is to make the Valley Giants simple and effective, strong and reliable. I want them to be relatively inexpensive, damage resistant, and repairable if they get dropped, etc. If someone else has a better idea of how to make big cams at the same price, good for them. But, that is my idea of how climbing gear should be made. I met Chouinard and Frost at the GPIW when I was 14 years old, and the robustness of their gear always impressed me. When you're way, way up there, having an epic, the last thing you need is for your gear to require pampering, and to not be up to the task. Just the idea that your gear might break is a psychological burden that you don't want during an emergency.
Since you asked about how many falls the Valley Giants have realistically held, I offer this:
Pam Pack told me she whipped repeatedly onto Valley Giants when she was working the Gabriel roof crack in Zion. These were falls out of a horizontal roof crack onto gear that could be many feet away. One bad cam would have meant a crippling ground fall. Last October she told me that the Valley Giant is the only big cam she's ever used that she trusts to fall onto. All those other big cams had single stems, which she also said do not work for her.
There is nothing wrong with pusher-piece cams, as long as people recognize them as such. I used to make magnesium superlight cams. I stopped making them because I couldn't be sure that people would understand that they were relatively weak. And I saw, first-hand, that even awkward aiding on those cams could deform the lobes in a way that was wholly unexpected. Climbing is dangerous enough, without using gear that is marginally strong enough.
A lightweight cam is like a sailplane: perfect for smooth sailing in clear weather. But you wouldn't want to be up there with one when the conditions deteriorate, and suddenly you're fighting for your life and depending on a delicate machine.
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Trashman
Trad climber
SLC
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Jun 29, 2017 - 01:20pm PT
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Great comparison Tom. Your Mg cams came up as my Mech Eng wife and I were playing w the cams side by side last night. Comes down to proper use and understanding your tools.
Seeing the way the climbing public has totally misunderstood or ignored the proper application of skinny runners, small cams, UL cams, etc, I don't think you're far off in your a*#umptions about the market.
As I said earlier, thrilled to have both of these tools in the quiver, thanks for keeping us safe out there.
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Tom
Big Wall climber
San Luis Obispo CA
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Jun 29, 2017 - 01:55pm PT
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^^^^^^^^^^^^^^^
The proper approach is to use the appropriate gear, which is often a mix of different things. Big offset brass nuts and small Aliens basically do the same thing, but sometimes one is better than the other.
If you are doing Moby Dick Ahab, a pusher piece is what is appropriate, because the chance of requiring a full-strength big cam there is negligible. But, on routes like Excalibur, Son of Heart, Jersey Turnpike (and maybe even the Salathe) having only lightweight pusher pieces in the largest sizes would be risky. If your crack widens to the point that you need to abandon your 9-inch cam and climb above it, do you really want it to be a pusher-piece? It's not likely you'll fall out of a squeeze chimney, but it's not impossible, especially if you run out of gas, or cramp up.
Regarding the above comment about the width of big cams, yes, the thinner they are, the more they tend to walk. But, the spring tension plays a big role, too. A long stem provides more leverage for rocking a cam back and forth, and making it walk. A runner clipped to a big cam is generally enough to isolate it from the moving climbing rope. A short quick-draw is hardly useful at all, which is why I don't even put them on the Valley Giants.
EDIT:
SomebodyAnybody, how in the hell did you wreck that #2 Camalot? How is your back doing, after taking that fall?
The real question is: which one of these big cam designers is a better kisser? My money is on Tom
That is not a fair contest. I have many more years experience. I was sneaking off to kiss girls in 1972, when I was ten years old.
I am old enough to remember Eiger Death Ovals, a few of which I actually owned. So, I know that sometimes gear that looks strong is not. That is why I am so obsessed with getting the message out there to know the limitations of your gear, and to respect those limitations.
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blahblah
Gym climber
Boulder
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Jun 29, 2017 - 02:30pm PT
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I seem to recall seeing that gold camalot photo somewhere on the Internet, and as I recall, the damage was not from a fall. But perhaps the poster will enlighten us.
Seems like 'ol Tom is doing some passive/aggressive insinuation that the Merlins are a "pusher piece" without saying it directly.
Would be nice to see the response.
(Lest this come across as busting Tom, I agree with the comments that all the artisan cam makers are providing a very interesting and potentially valuable service. I think all of us who may buy these sorts of things know or should know that they are all at least somewhat experimental and there are no performance guarantees.)
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Clint Cummins
Trad climber
SF Bay area, CA
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Jun 29, 2017 - 04:24pm PT
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... (and maybe even the Salathe) having only lightweight pusher pieces in the largest sizes would be risky. If your crack widens to the point that you need to abandon your 9-inch cam and climb above it, do you really want it to be a pusher-piece? I've climbed the Salathe' twice, with a much sketchier giant cam (Kuate).
I definitely didn't trust the Kuate to take a lead fall, so I didn't even take it on the Hollow Flake.
I just went for it with the lead line and 2 biners for the belay (also tagged up the haul line using the lead line, just barely).
A giant cam is useful on these pitches:
p21 (short ow below The Alcove / El Cap Spire)
p23 (crack above El Cap Spire - ends in squeeze size but I used holds out left)
p36 5.11a narrowing squeeze/ow. Just one aid move on the giant cam to a 3.5" crack (#4 Friend). But if the giant cam blows you would hit a ledge.
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Tom
Big Wall climber
San Luis Obispo CA
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Jun 29, 2017 - 11:11pm PT
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Passive-aggressive insinuation that the Merlin is a "pusher-piece" is spot on. I would really like to see a Merlin cam that has been severely abused, in the same way that a brand new Porsche 911 gets slammed into a wall to validate its safety design. It hurts, but validation is a necessary part of engineering.
Because I have seen big cams behave oddly, with the lobes folding sideways, I want to be sure that this is understood by other people. It is not at all obvious that there are very high lateral forces on the lobes when the stem is pulled straight down. A small cam doesn't behave the same way: the axle typically breaks first.
Simply scaling a cam from small to large is analogous to building a skyscraper using the technology of a three-story building. Louis Sullivan understood that he had to re-invent the building structure in order to successfully build the first skyscraper, the Wainright Building, in St. Louis, Missouri. He used a steel frame, with non-structural masonry infill, which was a remarkable innovation at the time, and which is still used to this day.
Structural innovation usually requires testing and development, to ferret out the unexpected behavior that is typical of such innovation. The Tacoma Narrow bridge in Washington was a modern design in 1940, but the roadway was torsionally flexible, and the bridge oscillated and fell into Puget Sound during a mild gale; the Golden Gate Bridge was subsequently refitted with diagonal trussing below the roadway to form a torsion box beam to prevent that sort of failure. Burt Rutan masterfully designed the Beech Starship airplanes from fiber composites, but they were later all repurchased and destroyed hy Beech because of concerns that they might present a future litigation hazard. Prince used to make all-carbon fiber tennis rackets, which were light, stiff and strong, but also brittle. Today, they have learned to mix glass, kevlar and other less-stiff fibers in tennis rackets to make them less susceptible to cracking. Kevlar used to be the go-to supercord for slinging chocks and Hexcentrics; later, it was known that kevlar was prone to sudden, brittle failure under certain conditions. The Tower of Babel fell down. And so forth.
If it seems like I am dissing the Merlin cams, it is because I want any weaknesses to be discovered during testing, and not while they are in use.
It's all fun, until somebody gets hurt.
You kids don't climb so rough. Somebody's gonna start crying.
 Mr. Blonde
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Matt's
climber
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Jun 29, 2017 - 11:31pm PT
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Tom- your desire to build a safe cam is commendable.
In my previous question, I asked you how many real falls valley Giants have experienced.
You essentially answered that Pamela pack has whipped on them.
At the end of the day, we are taking about really small datasets-- very small number of cams ever made, and even smaller number of falls. It is probably a bit overzealous to immediately proclaim your design to be safe, and the Merlin design to be a body weight only unit.
Best
Matt
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cavemonkey
Ice climber
ak
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Jun 30, 2017 - 12:22am PT
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Truly spectacular having these two fine men making wide cams for us timid folks
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cavemonkey
Ice climber
ak
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Jun 30, 2017 - 12:25am PT
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That scabfest on abracadeaver turned in to a one arm pull-up contest
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nah000
climber
now/here
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Jun 30, 2017 - 12:36am PT
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Tom wrote:
But, for the same price, the Merlin does not provide the same strength as a Valley Giant. But, then again, maybe today, with sticky rubber, ultra-thin lead ropes, microlight carabiners, and a climbing culture weaned on stories about free solos of Half Dome and El Capitan, the strength of a gear placement is no longer relevant.
So, just in case anyone out there wants a "high school shop project" that isn't just a pusher piece, but can actually hold a fall, or be used as a hauling or rescue anchor, and that has over fifteen years of proven use, I will have some more Valley Giant cams ready soon.
There is nothing wrong with pusher-piece cams, as long as people recognize them as such.
Passive-aggressive insinuation that the Merlin is a "pusher-piece" is spot on.
Simply scaling a cam from small to large is analogous to building a skyscraper using the technology of a three-story building.
i don't know if you care... but in the case that you might, your statements above lack professionalism.
they lack professionalism, as in each case they contain statements and/or insinuations that are, given the merlin cams current dearth of testing, simply not knowable.
while you have every right to ask for more testing, to use the language that you are using, when you also build large cams, is to step on some interesting ground.
if this was a bigger market, and there was real money at stake, you would have already received or would shortly be receiving a letter from a good lawyer.
you may not care, and that's your deal.
but you, by all accounts, make a damn good cam, and all you are doing as of your last few posts is dragging your own name through the mud [to at least this observer].
i do hope the merlin cams get more rigorous testing, at some point... but at the end of the day, until they do, buyers will just have to accept the unknowns for what they are...
name calling; unproven insinuations; and aspersions cast on the design process, theoretical modelling and testing that has been done, only makes the person casting stones look less in the eyes of those who understand and accept that the new cam is a bootstrapped project that has only had limited modes of testing.
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JoeSimo
Trad climber
Bay Area, CA
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Jun 30, 2017 - 10:22am PT
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I won't be satisfied until someone makes a #100 cam. THINK OF THE CLIMBING POSSIBILITIES!
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Late Starter
Social climber
NA
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Jun 30, 2017 - 12:21pm PT
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Tom...Sent you a message!
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blahblah
Gym climber
Boulder
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Jun 30, 2017 - 12:35pm PT
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if this was a bigger market, and there was real money at stake, you would have already received or would shortly be receiving a letter from a good lawyer.
Real-life laywer here (although a terrible one, as I've learned from ST feedback).
If I were designing, hand-making and selling equipment on which people's lives depended, I think "recieving a letter from a good lawyer" [relating to something like false advertising / product disparagement, I presume?] would be pretty far down on my list of legal concerns.
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Jon Beck
Trad climber
Oceanside
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Jun 30, 2017 - 12:44pm PT
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talking shlt is legal, as long as the talker is offering opinion, regardless of the validity. Promoting false facts is a different story.
Tom only said he would not trust a Merlin to take a fall. It becomes a problem if Tom falsely said "I took a short fall on a Merlin and it failed".
Great discussion on large cams, thanks to both the builders, I look forward to getting my pusher piece :)
God damn, the pusher
God damn, I say the pusher
I said God damn, God damn the pusher man
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Alexey
climber
San Jose, CA
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Jun 30, 2017 - 02:18pm PT
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it is very annoying to read smart ass lengthy passive-agressive lecturing about Tom's professionalism.
back to the subject. I have VG #9 for 5 years, using it [ rare]on some flares in Yos and Moab for free climbing. I never really had a fall which can be qualify as fall , but felt [ subjective] that VG#9 is stable piece because how it design [ proportions size to width] and mentally OK to fell .
I get Merlin#8 because on some routs it nice to have 2#9. The design is slick and light. It felt really light and nice looking. trigger lock was hard to get for me, but Erick help with video. It still not straight forward and hard to make trigger lock with both hands without table . If you go for multi pitch flare [ I don't] not sure you can lock it after first use. I compared Merlin vs VG side by side and Merlin is much more narrow.
I tried Merlin once on route which is wired for me and did not feel the piece is stable as VG because of it width [ subjective feeling] but I will use it again and probably will feel differently.
Anyway, I am satisfy with both Merlin#8 and VG and think it nice to have both of them for diversity.
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