Rigid-stem friends

flynn wrote:We still have and use RSFs, including some first-generation, nutted-axle numbers. They work great! As the trigger wires break, though, they may perforce get turned into paperweights. Damn.

Flynn: It's pretty easy to repair the trigger wires. For tools all you need are pliers and diagonal cutters. Wire and crimps are available at bait and tackle shops. I've used small copper tubing for crimps and guitar string or bicycle cable for wire.

Over in the UK forums they talk about using plastic "strimmer" (weed whacker) cord and melting the ends to make a "blob". They claim it lasts a long time. But, I haven't seen the thin (1-1.5mm) weed whacker cord here in the States.

patto wrote:This thread makes me regret selling my forged rigid friends. :-( That said I like my cams, and I love Totems! I've never seen something grip as well as a Totem cam.

What, you're saying that totems don't pull out as much as your other cams? How often have you had failures with other cams?

The bit that rgold and others mentioned about tied off rigid friends being more stable in some horizontal placements is interesting; I'd not considered that before. But, that benefit has nothing to do with them being rigid, and everything to do with them being possible to move the load from the end of the stem up to the head of the cam, right? So, if some other manufacturer could make regular, modern, flexi-stem cams that were possible to tie off at the head, those would probably still be superior to rigid friends, right?

And I agree that the biggest advantages of rigid friends are that they are/were cheap, and not heartbreaking to leave on a route. I have two sets, that never get used unless I'm going to the Creek.

camhead wrote: What, you're saying that totems don't pull out as much as your other cams? How often have you had failures with other cams? The bit that rgold and others mentioned about tied off rigid friends being more stable in some horizontal placements is interesting; I'd not considered that before. But, that benefit has nothing to do with them being rigid, and everything to do with them being possible to move the load from the end of the stem up to the head of the cam, right? So, if some other manufacturer could make regular, modern, flexi-stem cams that were possible to tie off at the head, those would probably still be superior to rigid friends, right?

I believe you've just described Totem cams.

camhead wrote:So, if some other manufacturer could make regular, modern, flexi-stem cams that were possible to tie off at the head, those would probably still be superior to rigid friends, right?

I seem to recall you having a cam like that... Still working on the racking issues, sadly.

:-(

Gunkiemike wrote: I believe you've just described Totem cams.

How so? Neither really seem to fit the bill IMO.

Aric Datesman wrote: How so? Neither really seem to fit the bill IMO.

IIRC (only used them one day) Totems don't load the lobes through the stem.

True, but they're flexible all the way to the attachment on the lobe, which prevents any of the leverage effect.

The way I understand it, the rigid stem provides more leverage in a horizontal placement than a flexi stem. So simply adding a tie off point closer to the cam head of a flexi cam would not accomplish the same thing.

Of course I'm relatively uneducated compared to the people who are still following this thread - so maybe I misunderstood.

Yup, you've got it right.

Aric Datesman wrote:True, but they're flexible all the way to the attachment on the lobe, which prevents any of the leverage effect.

That's the whole idea: minimize, or in the case of the Totems, eliminate the leverage. Cuz leverage is bad, at least that's how Camhead and I understand what rgold has said on the subject. I don't personally have anything to add one way or another; just pointing out the design feature of the Totems.

gunkiemike, i love a .45 too but if you ever get the chance to try a sig .40.

my new fav by far.

Gunkiemike wrote: That's the whole idea: minimize, or in the case of the Totems, eliminate the leverage. Cuz leverage is bad, at least that's how Camhead and I understand what rgold has said on the subject. I don't personally have anything to add one way or another; just pointing out the design feature of the Totems.

I hope RGold clarifies, because what you wrote is not how I'm understanding what he wrote. I'm reading that leverage is bad when there is a long moment arm away from the placement and you can bend the stem. But leverage can be good when it's close to the rock and helps the cam to "cam". The first case he mentions is a horizontal crack and the second case is a vertical crack.

RGold wrote:In the first case, the downward load on the stem produces an outward force on the cam which is a fraction of the total load, so it would take a lot to extract the cam. I know of some rigid-stem placements that were made in flaring horizontals in the Gunks BITD that might not hold at all with today's flexible stems.

^^^^ Here I'm picturing a horizontal placement in a shallow crack with the gunks tieoff almost right at the edge of the rock. The rigid stem is resting on the rock at the bottom lip of the horizontal crack. The crack is not deep enough so that the gunks tie off turns the corner over the edge. Any force is downward and trying to pull the rigid stem into the rock lip. Outward force on the cam is somewhat less in this circumstance. A flexible stem would "turn the corner" and provide more direct outward pull.

RGold wrote:In the second case, a flexible stem loads the cams almost perpendicular to their expansion plane, nearly nullifying the mechanical principles that make a cam work. The rigid stem provides torque that gives the cams a chance to expand against the crack walls.

^^^^^ Here I'm picturing a cam placed in a shallow vertical crack with the stem trying to stick out parallel to the ground. With a flexible stem cam, the load on flexible stem cam is almost parallel to the cam axle or as RGold words it "almost perpendicular to their expansion plane" and has little torque. Like it makes the cam want to slide vertically rather than rotate.
In that circumstance, a tied off rigid stem would minimize the moment arm but still provide some rotational torque that tries to move the upper lobes outward and the lower lobes inward. However, the lower lobes can't go very much inward because it is a shallow crack.

At least, that's how I read it. Corrections are welcome.

i read things exactly as wivanoff describes.

Yup, wivanoff's got it. I recall a discussion somewhere a long while back (RC?) that dug into the issue and had some great diagrams that made the how&why more easy to understand. Don't have a link handy though...

I think we need more rigid friend talk. I had them in the past, but my partners would complain about them, especially in California. This is strange, since they are light, strong, and don't really need tie-offs on granite. I move back to North Carolina, and my new buddies are using them in horizontals with tie-offs and swear by them. The straight dope on friends is this: wide heads like camalots with less range, but a cam angle that is better in flares, and with the tie-offs they are better in horizontals. It is the gap in the trigger bar for the trigger that is the weakness. Once they are tied off, even if the tie off point is sticking out beyond the horizontal, they're bomber! And, as Eddie Medina said way earlier in the thread, the stem itself has it's own camming effect which makes the placement even more solid.