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Let's talk about cam placements

Original Post
Mathias · · Loveland, CO · Joined Jun 2014 · Points: 306

Seems a little slow on here today and it's slow at work, so....

I've noticed (and been told) that small cams are tricky to place effectively. Tiny little lobes and not much movement in them, so it seems like where one just won't quite fit, the next size down just doesn't seem like it's secure enough. After an unfortunate incident in some chossy rock, I've started to pay even more attention.

I followed an MP member, ROC, on a couple routes in Eldo one saturday a while back and I noticed something whilst cleaning his placements. At first I was a little confused at how difficult it seemed to clean some of his cams. Then I realized why. He was contracting the lobes and then snaking the cams into constricting placements so that they simple couldn't come out in the direction of pull. Which, once I thought about, I decided was quite clever. Then I started to remember (and notice) that others I've climbed with do this too. And now I've started doing it too.

It seems like a good way to secure smaller cams, and also to prevent walking. I'm wondering if this is something most of you do. And if it is, were you taught to do it, or is it just one of those little tricks learned with time?

Joy likes trad · · Southern California · Joined Jul 2012 · Points: 71

Truly small gear is not rated for a full fall so to get the most out of it you need to place it very well/where it could not possible fall out.

Benjamin Chapman · · Small Town, USA · Joined Jan 2007 · Points: 18,818

Mathias,
Yes and no. Makes perfect sense to me. When cams came out climbers made the erroneous assumption you could plug cams in anywhere. With that attitude it's not surprising how many cams fail. Placing cams in constructions where they can't pull without the rock failing is a wise strategy. Just be sure to use a longer sling or you'll be leaving some fixed cams for the "booty hunters."

djh860 · · Unknown Hometown · Joined Dec 2014 · Points: 110

I slot any cam size I can

Kerwin Loukusa · · PNW · Joined Aug 2013 · Points: 135

If there is a pod/constriction that will keep my cams from walking, I will always place it in the pod as long as I think the cam will not get stuck (ie. placement is to tight). Sometimes this means that I slot down, sometimes I slot up, etc. Cams work perfectly fine in parallel sided cracks, but getting crafty with placements can often help keep the small cams in place. Be careful though, as your follower may not know how you placed it and may have a hard time getting it out. I often will yell down to my follower and indicate if I slotted a cam, if it is possible to communicate with them.

johnnyrig · · Unknown Hometown · Joined Dec 2011 · Points: 105

I would love to see pull-test data on cams placed in cracks that flare inward and outward. It would also be interesting if someone could set up a test rig that measures and correlates expansion force with the amount of force put on the stem, and the amount of flare in the crack.

I'm suspicious of placing small cams (or large ones for that matter) in "pods". Could the inward flare of the pod actually cause the lobes to retract?

Joy likes trad · · Southern California · Joined Jul 2012 · Points: 71
johnnyrig wrote:I would love to see pull-test data on cams placed in cracks that flare inward and outward...?
it's more about them staying put and not walking/falling out of the ideal pull orientation than about what the overall load capacity of the device is.
Greg D · · Here · Joined Apr 2006 · Points: 883
gription wrote: it's more about them staying put and not walking/falling out of the ideal pull orientation than about what the overall load capacity of the device is.
Well, not exactly.

johnnyrig wrote:I would love to see pull-test data on cams placed in cracks that flare inward and outward. It would also be interesting if someone could set up a test rig that measures and correlates expansion force with the amount of force put on the stem, and the amount of flare in the crack. I'm suspicious of placing small cams (or large ones for that matter) in "pods". Could the inward flare of the pod actually cause the lobes to retract?
This has been done.

The generic concept of the cam, as you know, a downward force or a pull on the stem translates to an outward force on the cam lobes roughly perpendicular to the downward force. As long as this outward force generates enough friction between the lobes and the rock to oppose the downward force, the cam will hold.

When the crack is truly parallel, the cam will contact the rock at the "design cam angle" which is less than perpendicular by about 13 degrees. Most people know this stuff.

Here's where it gets a little more interesting:

If the crack is not parallel and constricting like an upward "V", the cam angle will get larger (and much less than perpendicular) and the outward force will be less. In this case, the cam behavior will be trending toward passive pro and trending away from active (camming) pro. And the forces on the cam axle and the rock less.

If the crack is not parallel and flaring like a downward "V", the cam angle will get smaller and as it tends toward perpendicular the outward forces tend toward "infinity". In this case, and in a small range, the cam's theoretical holding power is increasing. But, there is more force on the cam axle and the rock. Both have limitations and manufacturers don't recommend this.

Now to answer the op:

Small cams have much less margin of error. Less surface area, smaller expansion range, weaker components. So, slight movement, tiny bit of rock breaking, etc can render a small cam useless. Again, most people know this.

Hence, placing small cams in constrictions may add some security. It may help to keep it in place. It may help if camming fails and the piece slips into a constriction rendering it more like passive pro.

If you want more info Bear and Gold will post thousand word essay in 3, 2, 1.....
john strand · · southern colo · Joined May 2008 · Points: 1,640
Benjamin Chapman wrote:Mathias, Yes and no. Makes perfect sense to me. When cams came out climbers made the erroneous assumption you could plug cams in anywhere. With that attitude it's not surprising how many cams fail. Placing cams in constructions where they can't pull without the rock failing is a wise strategy. Just be sure to use a longer sling or you'll be leaving some fixed cams for the "booty hunters."
100% wrong placing cams in constrictions limits movement..you place nuts in constrictions,,not cams. Longer slings mean nothing.
Donovan Allen · · Soft Lake City · Joined May 2012 · Points: 356

Start using stoppers. ... Problem solved?

Muscrat · · Unknown Hometown · Joined Oct 2011 · Points: 3,625
DoNstamos wrote:Start using stoppers. ... Problem solved?
+1
And next you're gunna say 'Don't forget the hexes'!
HA! i carry both. Find the story of John Long, Trashcan Rock in J-Tree and the Volkswagen....
We're showing our ages and with ages comes....comes...oh forget it; i did.
Donovan Allen · · Soft Lake City · Joined May 2012 · Points: 356

I prefer calling a hex a cowbell. I got a fever. And the only prescription is passive gear!!

bearbreeder · · Unknown Hometown · Joined Mar 2009 · Points: 3,065
Metolius cam instructions

Most microcams arw NOT rated passively ...

If you place em in a constriction which doesnt have parallel sides, the lobes may open up and umbrella in a fall

Zeros, small camalots/friends/dragons are rated passively and you can places those in constrictions just fine

Wuz dat ai douzand werds???

;)
Steven Lee · · El Segundo, CA · Joined Mar 2014 · Points: 385

I was actually wondering the same thing - me being a noob trad leader. I put this in while in Tahquitz. Is this what you're referring to Mathias? What does the MP community have to say about this?

For the record, I considered it marginal.

X4 cam placement on Left Ski Track. Good opportunity?

Mathias · · Loveland, CO · Joined Jun 2014 · Points: 306
polloloco wrote:I was actually wondering the same thing - me being a noob trad leader. I put this in while in Tahquitz. Is this what you're referring to Mathias? What does the MP community have to say about this? For the record, I considered it marginal.
A little like that. I'll try and describe it better using an example from this weekend.

I found a short slot in an overhang at the end of a Chimney. The slot was maybe 2" long. I had a #1 Master Cam but didn't bring the zero. The slot was tighter towards the top than the bottom and flared as it went in just slightly, but was not deep and quickly tighten back up as it went in. The cam, with lobes fully retracted would not slide through the front of the slot but if I angled it with the axle's end inwards, I could get the cam past the edges of the slot and then turn it and slide it upwards towards the top of the slot. It would not pull straight out from here, but when I released the trigger, the lobes sat in a cammed position, all touched rock. I wiggled it back and forth, tried to pushed it in and pulled it out. It didn't really move. The lobes still sat well and it was angled closely to the anticipated direction of pull. I considered it good.

So I'm not saying I contract the lobes, slip a cam into a constriction and just let it open all the way up. But this placement seemed unlikely to take a nut and hold it, as if the nut came loose, it would fall down to the widest section of the slot and just pop right out the way it went in. If the wide section had been at the top and the slot hand been more vertical than overhead, I *would* have used a nut. I always try to look for passive placements first.
Anonymous · · Unknown Hometown · Joined unknown · Points: 0
polloloco wrote:I was actually wondering the same thing - me being a noob trad leader. I put this in while in Tahquitz. Is this what you're referring to Mathias? What does the MP community have to say about this? For the record, I considered it marginal.
Really looks like an ideal spot to stick a nut in, but than hard to tell from a picture how the crack really constricts.
Donovan Allen · · Soft Lake City · Joined May 2012 · Points: 356

^+1!!

Mathias · · Loveland, CO · Joined Jun 2014 · Points: 306
ViperScale wrote: Really looks like an ideal spot to stick a nut in, but than hard to tell from a picture how the crack really constricts.
Yeah, pretty hard to o say from just the one angle, though the small nub on the right side (just where the trigger tube ends and the wires attach) looks like something that'd catch a nut pretty well, to me.
Steven Lee · · El Segundo, CA · Joined Mar 2014 · Points: 385

Yeah it's kind of hard to tell from the picture, but the right side nub doesn't extend into the cavity, it was more parallel behind the nub - you can tell by the fact that it covers the line of sight to the edge of the cam. The left side was slightly flaring outward. Either way, I think I would have been better off going lower in the crack and using a DMM offset nut, but I wanted to try that cam placement out.

Sorry - hope I didn't derail the OP's thread.

john strand · · southern colo · Joined May 2008 · Points: 1,640

Lower down it that placement ,,maybe..put in 2 pieces and see which works better. i find the idea of passive placed cams silly

Shelton Hatfield · · Unknown Hometown · Joined Apr 2011 · Points: 650

I have a person anecdote. The discussion seems to be more about a cam holding or not, but I'll add my 2 cents. I once placed a #.3 camalot (not tiny but not big) in a tight pod with no room to move and proceeded to take two decent whips on it (30+ish feet). After I finished the pitch my partner cleaned the cam and remarked on how mangled it was. The axels had become very bent. I attributed this to the cam being unable to rotate so that the stem would truly be pointed in the direction of pull, putting unnecessary force on the axels. I did look at the cam inbetween falls, but didn't fully take it out and inspect it (a mistake), so I'm unsure if any damage occurred from the first fall. I kinda thought the cam may have been saved had I given the rope time to rest inbetween falls and perhaps retied my knot, as both climber and belayer noticed the second catch being much "harder", but that's another can o' worms.

Bottom line is I wish I'd used a nut. Less expensive and would've been bomber.

Guideline #1: Don't be a jerk.

Trad Climbing
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