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vanilla_gorilla
Mar 9, 2008, 5:38 AM
Post #26 of 31
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Registered: Sep 13, 2007
Posts: 10
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I understand the concept of a varying cam angle, i have personally cmm'd all of my own cams and can tell you which ones vary and by how much and which ones dont (max cams included) and just how "much" advantage a double axle gives you ect. I realize im a bit stubborn but i still dont understand why, or i guess i just dont buy it.
This theoretical coefficient of friction looks good on paper but it simply doesnt apply. It is pull testing (shear stress) on real rock that determines cam angles. If the rock cant hold a 14 degree cam angle then you shouldnt be placing cams in it. If a manufactures sells a varying cam angle with a 18 (to remain nameless) out on the end with gaps already in a set of cams mathematically much less when there is an 18 deg out toward the end, and so has the selling point of fewer cams from finger to hands, i dont like it.
Once again this is just personal opinion, but i just dont like it. I think of a varying cam angle as an el camino, it is a blend of a car and a truck, but i just think it makes for a shitty car and a shitty truck.
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patto
Mar 11, 2008, 3:26 PM
Post #27 of 31
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Registered: Nov 15, 2005
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vanilla_gorilla wrote: I understand the concept of a varying cam angle, i have personally cmm'd all of my own cams and can tell you which ones vary and by how much and which ones dont (max cams included) and just how "much" advantage a double axle gives you ect. I realize im a bit stubborn but i still dont understand why, or i guess i just dont buy it.
Well come on then. Don't hold back. Tell us about the cam angles and how much they vary. Also how much does the double axle help by?
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adatesman
Mar 11, 2008, 4:05 PM
Post #28 of 31
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Registered: Jul 13, 2005
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vanilla_gorilla
Mar 12, 2008, 2:36 PM
Post #29 of 31
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Registered: Sep 13, 2007
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I going to do my best and hold off disclosing my data until i finalize my paper in may. I will post it when im finished.
Im surprised that you have not measured the cam angles of various cams yet. Without going back over and reading all of the last posts, i think i recall you mentioning something about solidworks (or any cad prog). that is all you need to find out which ones vary and which ones dont. with a little bit of playing around you can sketch a log spiral, scale it 100%, print it out and just look at it, its pretty obvious. the average printer is surprisingly accurate, in the ballpark of .002 per inch, more than accurate enough to show you the gross variance in cam angle.
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adatesman
Mar 12, 2008, 3:39 PM
Post #30 of 31
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Registered: Jul 13, 2005
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patto
Mar 15, 2008, 4:38 AM
Post #31 of 31
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Registered: Nov 15, 2005
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adatesman wrote: For example, a cam with a 13 degree cam angle with a 50mm retracted size will get 80mm as a single axle and 84mm as a dual axle, if it has 30mm between the axles. Not much of a bonus, given all the weight IMO.
Wow I didn't know that the dual axle design was that little of a difference! I bough a new set of cams 5 months ago. I was going to get WC but I managed to get 20% off BD at REI so I went with them. Makes me rethink my purchase. Still, I'm happy with my new cams.
It seems that the dual axle design is inferior. 5% expansion range doesn't seems that good compared to the disadvantages of extra weight and NO rotation around axis.
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