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Who else would like to see more wide cams on the market?
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By patto
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.

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By Matt Kuehl
From the desert
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...

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By Stone Nude
Sep 24, 2012
When dumb people have disposable income, hilarity ...
^^^^^^Words of wisdom.

I was thinking along the same lines the other day; I'd probably be psyched to find a different size cam that filled in a gap in the VGs, like a 10.5 or a 7.5, even better-that wasn't a brick hanging off my harness and I could place quickly.

The extended range deal really seems like it reached its high point with the Omega Links, which are debatably useful items, in many people's eyes. If you look at sales on Max Cams as well as Supercams, you will most likely see that for wide cams, a few folks checked them out and decided they were somewhat interesting, and the rest of us stocked up on BD 3s, 4s, and used 3.5s and 4.5s and moved on with our lives-as I understand, the Supercams were never made to fit larger than a #4 BD size, and, as Matt said, who wants to carry a 4 to place as a 2? I've never seen a Supercam on anyone's rack, and only once have I climbed on Max cams, which I didn't mind, but weren't amazing.

The bottom line for Aric though is pushing new designs, so scabbed-up crack hounds like Matt and myself will most likely be best served by ponying up the VGs, varying our arsenal between new and old BDs, and some Wild Country fat boys thrown in for spice. Big Bros are great when they work, which is definitely not everywhere. I've carried the monsters up OW/chimney routes to try to make use of them and gotten shut down. They're great for placements that they fit, but there's a reason they haven't replaced big cams and no one wants to fall on them.

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By Aric Datesman
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.

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By Greg G
From SLC, UT
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.

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By Aric Datesman
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.

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By DannyUncanny
From Vancouver
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.


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By Aric Datesman
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.

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By DannyUncanny
From Vancouver
Oct 3, 2012
Right now it's a combination of linear and exponential terms. If there was no friction, a linear spiral would produce a constant torque. The angle increases as the torque arm decreases. But to overcome constant friction rather than constant torque you would want a constant angle. So I just guessed something in between. This is assuming that the goal is a consistent trigger pull force which might not be true.

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By Stone Nude
Oct 25, 2012
When dumb people have disposable income, hilarity ...
Ok, no word on this for several weeks. Where are we at? Has a design been settled on or is this still in the kicking around ideas stage?

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By Greg G
From SLC, UT
Oct 26, 2012
The route in it's entirety.
Good thread bump Kill. My vote is for a stem in the design, but every designers plan are their own personal baby so I doubt my opinion will go very far.

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By Matt Roberts
From Columbus, OH
Oct 26, 2012
Hittin' Miguel's with the new Chimps in tow
It seems to be that Danny's design could pretty easily accomodate an optional stem that clamped on the axle, and had a trigger w/ wires that wrap the trigger bar. The conversion wouldn't necessarily be a crag-side mod, but it seems that it wouldn't be that difficult to adapt the design to have both possibilities.

Disclaimer: I'm not an engineer, but I did spend four hours in meetings with them this morning.

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By NorCalNomad
From San Francisco
Oct 27, 2012
Matt Roberts wrote:
It seems to be that Danny's design could pretty easily accomodate an optional stem that clamped on the axle, and had a trigger w/ wires that wrap the trigger bar. The conversion wouldn't necessarily be a crag-side mod, but it seems that it wouldn't be that difficult to adapt the design to have both possibilities. Disclaimer: I'm not an engineer, but I did spend four hours in meetings with them this morning.



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By Stone Nude
Nov 1, 2012
When dumb people have disposable income, hilarity ...
I'm just bumping here because I'm stuck working and dreaming of wide nastiness.

Any updates? Is the project dead-ended?

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By Aric Datesman
Nov 2, 2012
Nope, not dead. Just no time to work on it lately as I finish buttoning up the outside of the house I'm renovating before winter hits (250 feet of hand dug French drain through heavy clay and bamboo forest, several hundred pounds of stucco, paying someone to replace the roof). And now that's almost done I get hit with the hurricane and will be without power for a week or so....

Sigh... On the upside, camping at home means a flush toilet and proper bed. Thankfully the blower on the fireplace insert can run off a small inverter, so we have heat (unlike many of our neighbors). Not so fun is the live 240 volt line sitting on the sidewalk 20 feet from my front door, or the *possibly live* 35,000 volt line laying next to it. Police tape everywhere, and the power company has someone stationed there 24/7 to keep people away from the wires. Oh, did I mention I live in town? That guy's pretty busy. On the upside, watching the neighbor's tree burst into flames when the 35,000 volt line grounded to the ground line in the 240 volt bundle was quite fun.

Good times. Anyway, off to cleaning up debris at the in-process house. Lost a couple trees there, but otherwise no big deal.

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By Greg G
From SLC, UT
Nov 2, 2012
The route in it's entirety.
Good to know you're safe and sound Aric.

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By Aric Datesman
Nov 2, 2012
Thx. All in all, I don't have it so bad. Lots of good discussion and play-by-play on ST in the "OT: Sandy" thread. I've got a bunch of pics there, as do some of the other mid-atlantic folks. Only thing that bothers me is the guy a couple doors down who feels it's ok to be running his giant illuminated Halloween display while the rest of the block is without light or heat. The break happened between the pole in front of my house and the one in front of his, and the electric is fed from his side. What a dick.

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By Stone Nude
Nov 29, 2012
When dumb people have disposable income, hilarity ...
Checking in a month later....what's the wide word?

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By Aric Datesman
Nov 30, 2012
Still no time to work on it, but with the holidays coming hoping to still have a proto ready for testing by the end of the year. Unfortunately day job takes precedence, which is also why I only got out climbing once this year... :-(

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By Princess Mia
From Vail
Nov 30, 2012
Chillin' at City of Rocks
And so many are talking about ice...... Dont get me wrong, i love ice porn, but this thread makes me realize there is nothing better than OW porn....I think I must do a little more awful this season.....

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By Aric Datesman
Nov 30, 2012
FWIW, the current problem is I simply can't get my head around the math for the quasi-MaxCam thing. Seems a fairly straight forward problem with the effective lever arm being the cosine of the angle * length, but generalizing it such that it has an effective 14 degree cam angle across the entirety of the rotation is giving me fits. To the point that once I get time to work on it again I'm going to give brute force a try and see how close I can get with manually tweaking the log spiral to account for the change in leverage. But with a 2.5 year old running around and life in general, hobby stuff like this has taken a back seat. Sorry about that, but still hoping to get a proto ready by the end of the year.

-a.

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By Stone Nude
Dec 2, 2012
When dumb people have disposable income, hilarity ...
I hear you. I've been working around the clock lately, too. Hang in there, climb a few days before you worry about this crap.

K

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By brenta
From Boulder, CO
Dec 3, 2012
Cima Margherita and Cima Tosa in the Dolomiti di B...
Aric Datesman wrote:
FWIW, the current problem is I simply can't get my head around the math for the quasi-MaxCam thing. Seems a fairly straight forward problem with the effective lever arm being the cosine of the angle * length, but generalizing it such that it has an effective 14 degree cam angle across the entirety of the rotation is giving me fits.

Aric, some time ago, maybe a couple of years, I emailed you a .pdf file. Not sure you got it, but if you did, look up equation (4.6) and the discussion surrounding it. The differential equation is simple enough, but evaluating the derivative requires solving a nonlinear equation at each step.

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By DannyUncanny
From Vancouver
Dec 3, 2012
Aric Datesman wrote:
FWIW, the current problem is I simply can't get my head around the math for the quasi-MaxCam thing. Seems a fairly straight forward problem with the effective lever arm being the cosine of the angle * length, but generalizing it such that it has an effective 14 degree cam angle across the entirety of the rotation is giving me fits. To the point that once I get time to work on it again I'm going to give brute force a try and see how close I can get with manually tweaking the log spiral to account for the change in leverage. But with a 2.5 year old running around and life in general, hobby stuff like this has taken a back seat. Sorry about that, but still hoping to get a proto ready by the end of the year. -a.


I wrote a simple numerical solver to calculate lever arm cam curves. The basic idea is that the origin is the axle location. You input a starting lever arm location in x,y, and a starting contact location c_x. The contact curve is defined by c_x and c_y. For each increment c_y is defined by the horizontal distance from the lever arm to the contact point multiplied by the caming ratio. So a cam ratio of 0.25 is approx 14 deg. Do this for every incremental step in angle, while rotating c_x and you get your final curve.

So the equations I have xi and yi are simply a rotation of x and y by whatever angle theta. xi=x*cos(theta) - y*sin(theta), yi=x*cos(theta)+y*sin(theta). c_xi is simply the previous contact position, c_x(i-1) ad c_y(i-1) rotated by the angular increment, and c_yi is defined above, the cam ratio times the horizontal lever arm. To get an actual series of points along the curve, you have to rotate the c_x and c_y values backwards by whatever angle they are for.

Here is the excel file, maybe that will better explain the calculation. Sorry I didn't keep the same notation.

dl.dropbox.com/u/107337915/cam...
dl.dropbox.com/u/107337915/cam...
dl.dropbox.com/u/107337915/cam...

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By Aric Datesman
Dec 3, 2012
Thanks Brenta and Danny. Will see if your work speeds thing up when I get time. Sadly that's the thing that's lacking, and the reason this project stalled. To give you an idea, this was my day today:



Buddy came over and we took out ~2.5 cubic yards of clay and building debris (mostly large chunks of shale). Now that we got to the far wall the plan is to hook right and take out another 10 cubic yards, so that I can fix a pair of floor joists along the back wall (house is 150+ years old and needs a lot of this kind of work). Once that's done we turn around and thing about clearing out another 20 cubic yards the other direction so there's access to rewire the place and do away with any future termite concerns. All before he moves to DC in a couple weeks.

And this was after me hand digging 240' of French drain in clay the past couple weeks... :-(

Sorry this has dragged on so long, but with winter/snow coming life's getting in the way... Still want to get a proto done and to one of you guys by year end, so keep on me about it. :-)

-a.

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