Re: ATM Wiring Spiders

[Doug Tanaka <dtanaka@seanet.com>]

Dan,

I just made a wire spider for my scope and just made the adjustments 
through trial and error, loosening one side and tightening the other.  I 
used an archery string called 452 Plus.  It's just like the 450 Plus string 
I used in my string-truss dob, but half the thickness.  Because it's made 
of many very fine fibers it's hard to measure for thickness, but I would 
guess it's around .10".  It's not worth getting a spool, but if you'd like 
some (or anyone else), contact me offlist and I'll send you some.

The string has virtually zero stretch and can be stretched very taut, but I 
did find that there was a bit more vibration.  I solved the problem with a 
tip from Mark Holm (thanks Mark!) about the use of foam earplugs to damp 
vibration.  I had already used it on my fans and found it worked great, so 
I used it on the string  spider by cutting them into fourths, lengthwise, 
and tying them to the bottom of one "vane", through the strings of the next 
vane, and tying to the top string of the opposite vane.  The pieces of foam 
formed a "barber-shop-pole" pattern around the center tube.  This worked 
better than I had hoped, damping vibration in less than a second after 
rapping the secondary cage.

Doug Tanaka