[SEL] Life happens!!

[Rob Skinner]

  On Dec 21, 2007, at 12:15 AM, maytagtwin at aol.com wrote:
>
>  then tip them a
> little and use a boring bar to cut the internal taper.


That's quite insightful, Ron.  I'll try to describe the shackle  
arrangement used on elevators for many years -- an application that  
must have 100% reliability.  Perhaps it will help you in your design.

The "socket" of the shackle is a taper, as you described.  The big end  
is a more than twice the diameter of the wire rope.  The wire rope is  
threaded through the shackle, then the individual lays of the cable  
unwound so they "fray" out in a cone shape.  Each lay is then turned  
back in on itself, into the middle of the rope.  This is called a  
"rosette."

Each loop of the rosette must be exactly like all the others and the  
length appropriate to match the shackle.  When all the lays are done,  
the rope is pulled back into the shackle.  Being more than twice the  
diameter as it was originally, the rope will not pull through the  
shackle.

At this point, the rope/shackle will hold a load, but it will need to  
remain in service for many years and measures must be taken to assure  
than nothing shifts from it's current configuration.  While inverted,  
babbitt is poured into the shackle to lock the rope in place.  The  
babbitt is just to hold it all together;  it does not carry a load.

Have a Merry Christmas,
Rob