Re: [ATM] 64 pound single-pole 18" f/4.3

[William Lee <wjl12@comcast.net>]

Ross,

Was the original pole carbon fiber too? If not, have you noticed any  
difference in stiffness? I'm asking because my mind was trying to  
work around the $240 price for the tube, and was trying to consider  
alternatives!

Bill

On Aug 6, 2007, at 11:09 AM, Ross Sackett wrote:

> --- Gil McFarlane <gilboastro@yahoo.com> wrote:
>
>> Great looking scope Ross.  Can you describe the
>> carbon
>> fiber parts for me a bit and how they were to work
>> with?
>>
>> Did you find a source or have to make them?
>
> Hi Gil,
>
> The 2.125" diameter tube was from (I think)
> carbonfibertubeshop.com.  The 1/16" thick carbon-epoxy
> plates veneered on the pole support stock were from
> McMaster-Carr.
>
> The material was surprisingly easy to work with
> carbide tools, Dremel cut-off disks, and ordinary
> sandpaper.  You need to be very careful with dust and
> splinters, so I always had the shopvac running to pick
> up stray particles.  I cut the tubing with a diamond
> wetsaw for tile to keep the dust down.  Being a little
> paranoid I dressed up in Tyvec overalls, gloves, and
> closed splash goggles (fun in the summer Memphis sun).
>
> We all know how light and stiff carbon-epoxy is, but a
> major downside is that its strength can be limited to
> certain directions and planes.  For example, the
> tubing had to be supported by internal plywood disks
> to keep it from splitting at the clamping points.
>
> It made sense to use some carbon in this project
> because I was trying to save more weight.  The
> non-carbon blue version of the scope I took to the
> RTMC weighted 76 pounds; the new version with carbon
> and some sandwich construction reduces this to only 64
> pounds.
>
> Would I use carbon again, say in a conventional scope?
>  Nope: it is too expensive, finicky, and has safety
> concerns.  This scope was fun to build, but I will
> probably stick with wood and aluminum in the future.
>
> Ross
>
>
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