On Mon, 29 Sep 2014 21:41:56 +0000 (UTC), "Danny D."
wrote:

Oren wrote, on Sun, 28 Sep 2014 10:31:43 -0700:

Just curious. Is there a torque spec for those clamps? Or ...

I had forwarded this thread to the owner of the treehouse in the redwoods, who replied with the following ...
-----------

People worry too much.

I simply design for 10 times the expected load, and pay the premium.
Trying to finely engineer the solution where torque and special fasteners are important
is a way to save money, and I'd rather spend the money and not waste my time.
I've never seen a malleable cable clamp. Drop forged ones are cheap, and I use more than
normal anyway, not because I think they are needed, but because they help keep the cable
from slipping out of place on the wood block spacers.

The reason for keeping the U-bolt on the dead end of the cable is because the saddle has
a lot more surface area, and thus does not reduce the strength of the cable as much as the
U-bolt does. But they make dual-saddle cable clamps, for those who don't use the over-engineering
approach I do.

Each cable can support 7 tons, so the total weight of treehouse and occupants can be 14 tons.
(Although there will be other supports besides the cable -- one end will rest on the ground, and
another end will be anchored to the tree, and there may be other support cables used just to
make installation and leveling easier.)

If half of the weight is treehouse and the other half is people, we have 7 tons of treehouse
possible (although the actual treehouse will probably weigh less than 1.4 tons fully furnished),
and 7 tons of people (70 people, if they are all 200 pounds). I doubt we will ever have 70 people
in the treehouse -- they'd be shoulder-to-shoulder.
I hear that about over engineering stuff. When I was getting ready to
pour the floor for my shop I calculated the concrete thickness for the
various machines and then though about what happens if I move a
machine and then what happens if I buy a heavier machine or one with a
smaller footprint and so on. Then I realized how pointless this was in
my situation, So I had the concrete poured to 7 inch minimum
thickness, had fiber put in the concrete, and I put rebar and wire
mesh in place before the pour. It's a good thing too because I later
bought a lathe that covers 10 square feet with the base and sits on 4
9 square inch pads and weighs 8000 lbs.
Eric