by Cromlech » Mon Dec 20, 2010 11:16 am
HeavyC,
Great question, and one I've been wrestling with. My Treadwall (by cutting down the front legs and jacking up the back legs) has adjustment from 0deg to 28.5deg. The front legs of my A-frame are not quite vertical, to reduce any potential for of topling. I have several thoughts on moving past 30deg.
One of the main issues Bcombs ran into when he moved beyond 30deg was the reduction in lateral stability after he removed of the X-bracing. You do need to maintain the lateral stiffness of the framing, this can be done by internal or external bracing.
Even at 28.5 deg, I am a little concerned about the cable crimps failing and have fitted a dynamic safety tether, just in case.
Based on Bcombs experience running past 30 degree isn't a problem, as long as the chains remain square and in sequence. If they are not square they will get out of sequence. If they are out of sequence as little as 1/2" the wall will stop. If this happens, you have to use the "bolt" trick from the Brewer's Ledge site and re-square your framing.
I do recommend using white lithium grease to lube the panel channels.
PM me your e-mail address and I'll send you some sketches.
PLJ