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Who else would like to see more wide cams on the market?
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Sep 20, 2012
I agree. George Bracksieck
Joined Oct 4, 2008
1,086 points
Sep 20, 2012
tanuki
I will agree also. Lot's of great ideas here, but IMHO the "Max Cam" concept is not that easy to use. NC Rock Climber
From The Oven, AKA Phoenix
Joined Dec 6, 2009
121 points
Sep 20, 2012
Before you all pass judgement on the MaxCam-esque design, be aware that it will likely behave *very* different from a MaxCam due to having only a single axle rather than three independent ones, and probably no stem.

I'm thinking I'll simply hack apart one of my #2 MaxCams for proof of concept and see how it places and if the stemless design avoids the flop problem (which is what I personally believe is what kept them from catching on), as it would avoid having to do the calculations and model new lobes. Then again, I might actually have lobes for this designed already and tucked away somewhere. Will look tonight.
Aric Datesman
Joined Sep 16, 2008
145 points
Sep 20, 2012
dis NorCalNomad
From San Francisco
Joined Oct 6, 2011
116 points
Sep 20, 2012
Ranar wrote:
dis


-agree?
Aric Datesman
Joined Sep 16, 2008
145 points
Sep 20, 2012
Well, digging through my archives it looks last I played with this MaxCam-esque thing was Nov'11 - May'12, and the only models I built were 0.75BD / 1MaxCam sized. Given how long I've been thinking about it I think I'll finally get around to hacking apart my extra #2 MaxCam to see what it does, as chances of me getting out climbing anytime soon are slim (1 year into restoring a 1820's schoolhouse, and need to get it finished). Aric Datesman
Joined Sep 16, 2008
145 points
Sep 20, 2012
Grande Grotto
Aric Datesman wrote:
Before you all pass judgement on the MaxCam-esque design, be aware that it will likely behave *very* different from a MaxCam due to having only a single axle rather than three independent ones, and probably no stem. I'm thinking I'll simply hack apart one of my #2 MaxCams for proof of concept and see how it places and if the stemless design avoids the flop problem (which is what I personally believe is what kept them from catching on), as it would avoid having to do the calculations and model new lobes. Then again, I might actually have lobes for this designed already and tucked away somewhere. Will look tonight.

I wondered about how the lack of 3 axels would affect things. That was a major cause of the MaxCam issues.

With no stem, how do you provide predictable loading of the cams and prevent off angle loads? A cam with no stem, even canted a little bit seems like it would have all sorts of issues with loading out of plane from the lobes themselves? Being sure that the forces hit the cam correctly seems important (see Link Cam). Even the Totems have a quasi-stem to direct the cable loading in the correct direction.

I have ZERO time behind cam design Aric so shoot any of these concerns down if indicated by your testing
mattm
From TX
Joined Jun 2, 2006
1,238 points
Sep 20, 2012
FWIW, Matt, I'm not certain how Danny's pic above will behave either. But it looks remarkably like the idea I was batting around months/year ago and aside from the trigger is sound mathematically.

I've spent a lot of time with MaxCams, as my rack is mainly MaxCams and Zeros and frankly like them a lot provided they're used under 75% expansion. The rock where I climb is highly featured and rather Gunks-like (Eastern PA), so the offset stem is handy on occasion and there's been more than several placements I initially place the corresponding C4 and then replaced it with a MaxCam that fit the ruggedocity better. Out West, yeah, I can see MaxCam's not being ideal and found myself placing large Tricams instead (I'm on of *those* people). That said, my main concern out West was the flop issue in parallel cracks when placed towards the end of their expansion. Not entirely confidence inspiring, and this soft-goods-on-the-inner-lobes thing in theory does away with this issue.

Following from that, having a soft goods connection between the inner lobes means that there's no longer a reason for 3 separate axles and ultimately it reduces to a Totem Cam with a pair of Totem lobes connected in the center and regular lobes on the outside. I don't believe this idea falls under either the MaxCam or Totem patents, but would need to look closer if it were to become an issue (we're still batting the design for this around).

Anyway, I think this idea is worth pursuing through the mock-up stage at least, especially in the ultra-wide sizes where there's (physically) room for silly ideas for trigger mechanisms. If you don't mind, humor me for a bit while we work though the single axle MaxCam idea to see if it's worth pursuing. Depending how the single axle pushes, it might just be the cat's meow for OW TR.

-a.

(ps- does this mean you and I have buried the hatchet like USN and I did a couple months ago? I seem to recall you piling on when that went south, and would be pleased to find it trickled down... :-) )
Aric Datesman
Joined Sep 16, 2008
145 points
Sep 20, 2012
tanuki
Not passing judgement, just giving my opinion. If it came off as negative, that was not my intent. If you understand the issues that folks have with the Max Cam and found a way to deal with them, GREAT! I am excited to see what you come up with and 100% support your innovative thinking. NC Rock Climber
From The Oven, AKA Phoenix
Joined Dec 6, 2009
121 points
Sep 20, 2012
No prob, NC Rock. Was just poking Matt in a friendly way as last I heard from him was less than pleasant during my blowup with USN. USN and I are good now, so now hoping Matt and I can also bury whatever it is I offended him with as well. :-)

EDIT- just occurred to me.. is there a NCRockFencer? I might have mistaken you for someone else ages ago, and if so my apologies. The NC is the part that stuck in my head, and (years later) I realize you might not be the one I butted heads with! :-O

Long story short, I've got a rather single tracked/ADHD mind and when deep into a project can come off as a dismissive asshole. Been working on that a while, and want to make amends.
Aric Datesman
Joined Sep 16, 2008
145 points
Sep 21, 2012
tanuki
I don't know any NC Rock Fencer. You and I did have some words during the end of your tenure at rc.com, but that was years ago. No hard feeling here, and I hope that there are none on your end. Seriously wish you the best with this project and I am looking forward to seeing the final product. NC Rock Climber
From The Oven, AKA Phoenix
Joined Dec 6, 2009
121 points
Sep 21, 2012
That was you????????

Kidding, we're all good. :-)
Aric Datesman
Joined Sep 16, 2008
145 points
Sep 21, 2012
Grande Grotto
We're good. All recent discussion has been much more civil across the board for all parties so no issues with me.

And please don't take my critiques here the wrong way. I'm just adding my POV to the collective knowledge.

Looking forward to a good project here

Aric Datesman wrote:
FWIW, Matt, I'm not certain how Danny's pic above will behave either. But it looks remarkably like the idea I was batting around months/year ago and aside from the trigger is sound mathematically. I've spent a lot of time with MaxCams, as my rack is mainly MaxCams and Zeros and frankly like them a lot provided they're used under 75% expansion. The rock where I climb is highly featured and rather Gunks-like (Eastern PA), so the offset stem is handy on occasion and there's been more than several placements I initially place the corresponding C4 and then replaced it with a MaxCam that fit the ruggedocity better. Out West, yeah, I can see MaxCam's not being ideal and found myself placing large Tricams instead (I'm on of *those* people). That said, my main concern out West was the flop issue in parallel cracks when placed towards the end of their expansion. Not entirely confidence inspiring, and this soft-goods-on-the-inner-lobes thing in theory does away with this issue. Following from that, having a soft goods connection between the inner lobes means that there's no longer a reason for 3 separate axles and ultimately it reduces to a Totem Cam with a pair of Totem lobes connected in the center and regular lobes on the outside. I don't believe this idea falls under either the MaxCam or Totem patents, but would need to look closer if it were to become an issue (we're still batting the design for this around). Anyway, I think this idea is worth pursuing through the mock-up stage at least, especially in the ultra-wide sizes where there's (physically) room for silly ideas for trigger mechanisms. If you don't mind, humor me for a bit while we work though the single axle MaxCam idea to see if it's worth pursuing. Depending how the single axle pushes, it might just be the cat's meow for OW TR. -a. (ps- does this mean you and I have buried the hatchet like USN and I did a couple months ago? I seem to recall you piling on when that went south, and would be pleased to find it trickled down... :-) )
mattm
From TX
Joined Jun 2, 2006
1,238 points
Sep 21, 2012
Here is another fun animation playing around with the renderer. I changed things around a little bit, getting rid of redundant overconstraints on the stops, and offsetting the axle from the middle just a bit. Range is about 6" to 11.5". I tried shifting it way over, but the lopsidedness got kind of out of hand.

I thought about the trigger bar a bit, and the best I could come up with was a slightly elastic tether running through the main axle to the ends of the trigger. Either that or a sliding wire or bar, but then you end up with an extra thing sticking out. The third alternative is to turn the outer lobe contacts into an enclosed slot that has enough freeplay to keep the trigger in place but still allow the two lobes to be at different positions. Anyways I've attached the excel sheet that drives the basic design.

The axle is now almost 0.75" with the lobes press fit onto wide bushings for better buckling resistance and that also serve to space them apart.



curve excel sheet
DannyUncanny
From Vancouver
Joined Aug 27, 2010
78 points
Sep 21, 2012
You know, Danny, move that spiral for the retraction bar in a bit and you've got one hell of a cam stop. Aric Datesman
Joined Sep 16, 2008
145 points
Sep 21, 2012
It aready acts as a cam stop the way it is now. DannyUncanny
From Vancouver
Joined Aug 27, 2010
78 points
Sep 21, 2012
Actually, it does, doesn't it? With it free floating like that perhaps constraining it a bit more would be more reassuring?

Seems to me constraining it on the other lobe would reduce loading on it compared to loading on a spiral. Food for thought.

(edit to fix phone typos)
Aric Datesman
Joined Sep 16, 2008
145 points
Sep 22, 2012
Quick and dirty mock-up using a #2 MaxCam. Seems to push ok, and no amount of wiggling the red cord makes it move, let alone flop. I kinda like it, actually.

Aric Datesman
Joined Sep 16, 2008
145 points
Sep 22, 2012
I'm watching this discussion with interest.

I must say that I very very rarely "push" a cam into cracks. 99% of the time I place them in.

That said if the 1% of the time when I "push" the cam in is when I'm pumping out on a tough climb I don't wont the cam to umbrella or behave oddly.
patto
Joined Jul 9, 2012
0 points
Sep 23, 2012
Plumbers Crack
Good work on all these ideas guys! Gonna throw my 2cents though...

Is range really an issue?? I'm not psyched on dragging up a 12" cam to place it in a 7" crack. And usually after a certain width you don't need to keep pushing up a cam because the climbing becomes secure when you're totally inside the crack. So Bro's got you covered if yer tweakin' on the wider squeezes. (They are light and have great range as i'm sure previously mentioned in this thread)

I think the bottom line to make an advancement on large cams is stability (when placed) and cutting down weight of the unit ... with a decent emphasis on ease of use. To me these are the issues I find most problematic...
Matt Kuehl
From red rock
Joined Nov 29, 2010
1,384 points
Sep 25, 2012
All Killer No Filler wrote:
The bottom line for Aric though is pushing new designs...


Pretty much spot on, Killis. I've built a lot of cams, and anymore find it hard to get excited about conventional designs since they're so straight forward. Case in point, this #3 BD-sized Forged Friend knockoff only took me a couple hours to make using only a drillpress, hacksaw and file (including time spent making the tooling to wind the springs). Total cost was ~$35, iirc and while this one proof tested at 10kN with no damage the other one I made broke at something like 22kN.



A double axle cam is a bit harder due to the axle cutout being load bearing (need a fair amount of precision for this, so mill with a rotary table or CNC), but still not terribly exciting. Still not out of the question for this though; I just want to explore more interesting options a bit first.
Aric Datesman
Joined Sep 16, 2008
145 points
Sep 25, 2012
The route in it's entirety.
Aric you're killing it!

I've carried (not used) the VG's and thought that the cam was easy enough to handle. Quick deploy mid route remains to be seen, but the handling of the unit was sufficient enough for me to feel confident in my ability to place it accurately with speed. Danny's design above looks good for cutting bulk and weight, but looks to be more difficult to place proficiently. Something with a stem is crucial in my opinion strictly for handling, and less so for anything else.
Greg G
From SLC, UT
Joined Oct 3, 2008
599 points
Sep 27, 2012
Greg G wrote:
Aric you're killing it!



In a good way, I hope?

Anyway, I somehow managed to find time to machine up a proper axle for the hacked apart Maxcam the other day, and the more I play with it the more I like it. To the point that I'm considering hacking up my other Maxcams once I get this one sorted out.

Some thoughts, in no particular order:
1. I've come back around on keeping the stem, as a stemless design with large lobes will have issues with placement on account of the lobes hitting your wrist when fully retracted.

2. Much as I like Danny's bar-over-the-axle design, I think it might be awkward for chest-level placements due to getting your wrist and elbow properly oriented while in a OW. A traditional stem helps avoid this, and makes the trigger easier to design.


Gonna play with it some more over the next couple days and will probably work up some solid models for the first prototype.
Aric Datesman
Joined Sep 16, 2008
145 points
Oct 3, 2012
Here is another photo of how that trigger idea would actually work. The cam here is just a normal cam. I didn't bother drawing springs holding the washers against the cam lobe.

DannyUncanny
From Vancouver
Joined Aug 27, 2010
78 points
Oct 3, 2012
What function are you using for the curve for the (for lack of a better term) retraction curve? I had been thinking log would be obvious chogoofy it thing's get goofy when you you account for differing amounts of rotation. Haven't thought through it all the way though, as I'm currently working through modeling the lever thing. Aric Datesman
Joined Sep 16, 2008
145 points


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