Discussion Topic |
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| Messages 1 - 24 of total 24 in this topic |
Enthusiast
Sport climber
Port Townsend WA
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I'd stack that
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steveA
Trad climber
bedford,massachusetts
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I was a machinist all my life, and climbed for 45 years.
Try just buying the aluminum for the asking price; never mind the labor.
The physics remains the same, and it may not have the bells and whistles, but I bet the thing works fine.
Wish I had owned that type of thing BITD. but not sure I would of liked lugging that thing up the Steck-Salathe.
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MisterE
Social climber
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Couldn't work any worse than the 6" wedge of 4 X 4 that I cut and slung BITD to protect an Index, WA climb...
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Greg Corliss
climber
Bishop
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The larger the distance between the contact point on the rock and the axle the greater the torque applied to the axle from the cam. Torque = force x distance.The weekness of many large units is when the cams bend over and the unit folds over sideways under load
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Jaybro
Social climber
Wolf City, Wyoming
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Looks like a clean design. I wonder how wide it is across the axle.
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CalicoJack
climber
CA
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Topic Author's Reply - Nov 7, 2012 - 09:44pm PT
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Yeah - I was also wondering, maybe i can fish another pic outta him.
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BASE104
Social climber
An Oil Field
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A buddy of mine was stationed in Korea for a while, and he got a Korean Machinist to copy all sizes of friends.
They sucked, though.
The offwidth masters use super large hand crafted cams.
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Jaybro
Social climber
Wolf City, Wyoming
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It's been the downfall of many a home made giant cam. Like the one that came out in the rostrum, rattled down most of the pitch I was following and bonked me in the head!
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enjoimx
Trad climber
Yosemite, ca
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As long as it has the trigonometric spiral lobe characteristic, I'm sure it would work. Not going to be as light as the BD # 3 though!
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CalicoJack
climber
CA
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Topic Author's Reply - Nov 8, 2012 - 01:02pm PT
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Pretty narrow as it turns out ( ~3"). An interesting piece though...
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Roxy
Trad climber
CA Central Coast
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wow...and I thought homemade 'clif bars' were cool.
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hillrat
Trad climber
reno, nv
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Nov 15, 2012 - 11:41pm PT
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you want more info on it? should be delivered soon :)
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Ksolem
Trad climber
Monrovia, California
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Nov 15, 2012 - 11:56pm PT
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Back in the wild and crazy days I soloed Tobins at Dome Rock once, largely to escape the wrath of an easily enraged woman - but that's another story...
Along the way I plucked this out, looks a bit like the ebay cam.
Has "Gulag" stamped on the stem, and made of poor metal.
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CalicoJack
climber
CA
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Topic Author's Reply - Nov 16, 2012 - 12:06am PT
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Nice! Jumped in on the opening bid, but then forgot to check in on it after picking up some Yates Big Dudes. Would be interesting to hear a field report!
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hillrat
Trad climber
reno, nv
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Nov 16, 2012 - 12:10am PT
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yeah, i forget to check ebay stuff. usually when it goes cheap too! but now I'm broke... so this will be the last purchase for awhile. now if I could just get out and climb more...
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hillrat
Trad climber
reno, nv
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Nov 20, 2012 - 12:07pm PT
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I have this thing in my hot little hands now.
so i disassembled it to check it out. After graphing out the "ideal" logrithmic 14 degree cam angle spiral, its not even close. It doesnt even fit a 10 degree spiral which would put outrageous force against the rock and probably deform the cams and or axle. Also the springs appear to be no more than bent wire and one cam rides on the threads of the bolt used as an axle.
So enlighten me... Do i reprofile the cams, fix the springs and axle and then whip on it? Or do i take up tossing and huck it off the movntain like so much other gear thats no longer of use at the top of the cap'n?
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Curt
climber
Gold Canyon, AZ
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Nov 20, 2012 - 12:17pm PT
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After graphing out the "ideal" logrithmic 14 degree cam angle spiral, its not even close. It doesnt even fit a 10 degree spiral which would put outrageous force against the rock and probably deform the cams and or axle.
I wouldn't necessarily worry about a 10 degree cam angle. Cams routinely experience much higher forces than that when they are used in flaring placements. In fact, as the angle of the flare approaches the cam angle the range of the unit goes to zero and the forces become theoretically infinite.
Curt
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hillrat
Trad climber
reno, nv
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Nov 20, 2012 - 12:35pm PT
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Good point about flares. Although the super tight spiral also decreases the useful range, so reprofiling would improve this thing a couple ways. Come to thing of it, specialty cams could in theory be constructed with a greater cam angle specifically for flaring placements, though no doubt theres an outside limit to that.
Someone should build a dual load cell test jig with a crack that has an adjustable taper to compare pull out force vs cam expansion force, like this:
Sure wish i had the money to build it.
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hillrat
Trad climber
reno, nv
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Nov 20, 2012 - 01:47pm PT
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Thanks for that link.
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| Messages 1 - 24 of total 24 in this topic |
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