OFWW wrote, on Sat, 27 Sep 2014 23:55:45 -0700:

If you installed these without lock washers I would recommend you go
back up and at least put nylock nuts as safety nuts. Heating and
cooling will cause those nuts to walk off the u-bolts.

Thank you for that safety suggestion!
That is a good point. Safety is paramount.

This treehouse 50 feet in the air in the redwoods has to outlast us
and it has be safe at all times.

Since we didn't use lock washers on the steel clamps, I will advise
my neighbor and I will snap a picture of the results for you.

You will notice that we doubled up the two ends of the steel cable
as they wrapped around the tree, so that we'd always have two cables
supporting the bridge.

On the big tree, 125 feet away, we will add a wraparound additional
steel cable, so that the middle also has two cables.

Any other safety ideas are welcome, as we're just at the point now
where we can start hanging the suspension bridge from the two steel
catenaries.

For example, you will notice that we followed the rule as shown he
http://www.pirate4x4.com/tech/billav...dead%20end.jpg

Following that diagram, we put the "saddle" of the clamps on the
"live end" (the mnemonic we used was "don't saddle a dead horse").
http://www.pirate4x4.com/tech/billav...pe%20clips.jpg

Any other tips are welcome, as we're just now at the stage where
we have the ability to build the 125 foot long bridge starting
about 15 feet up in a pine, and then going straight across a
steep slope through the set of two redwoods, and then on to the
really big redwood 125 feet down the slope.

The treehouse will be in the middle of the bridge.