[Elecraft] DIY Hard-drawn copper wire

[Bill Frantz]

Trees are quite strong. When we do demonstrations by breaking 
equipment during cave rescue classes, we use trees as anchors 
and a truck with an electric winch attached to one tree. Some of 
these things break at several thousand pounds force. (We measure 
the force with a load cell.)

The basics for tree anchors:

(1) Make sure the tree is alive and healthy.
(2) Wrap the tree with a tarp or heavy cloth to protect its bark 
from damage.
(3) Then wrap it with 2" nylon webbing at least 3 times. Use a 
water knot to join the webbing. Leave the knot facing the load 
and pull the rest of the loops out to a carabiner or quick link 
rated for the expected load. This arrangement gives you a chance 
of being able to untie the know when you are finished. (2" 
tubular webbing is rated at 4000#. If you pull two loops, that 
is 4 strands and 16000#. Derate by 50% for knots, bends around 
carabiners etc and get 8000#.)
(4) If you are breaking things, such as #8 copper wire, cover 
them with blankets to minimize the danger of having them snap 
through the air.
(5) Keep everyone far enough away so flying wire won't hit them, 
or keep them in a closed vehicle.

73 Bill AE6JV

On 2/11/16 at 6:34 AM, edauer at law.du.edu (Dauer, Edward) wrote:

>I wondered what 700 or 800 pounds of shear force would do to an 
>automobile frame, assuming attachment to a suitable bolt 
>somewhere.  Or would the tree fall over first?
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