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Dear slide rule addicts,

I have good news.
I found a firm that supplies star gazer's needs 
including custom tubes for telescopes.

These are made of a sort of laminated paper similar to 
circuit boards. So it is cellulose fibre reinforced 
epoxide.
Advantages should be strength, low thermal expansion 
and low density (~1.3, half of Al); Strong enogh to 
make threads in it but still allows to use "normal" 
DIY wood working tools.
(To see a picture visit
http://gerdneumann.net/v2/deutsch/hp-tuben.html
regrettably there's no english version of this site)

Tolerances are 0.2 mm nominal, but they say it's 
normally around half that number.

Manufacturing length is around 1250 mm (four feet), 
enough for four slide rules. Cost around 75 � each.

There is even a possibility to have them ground to 
precise diameters on the outside but I do not have 
details on this yet.

I now ordered a first set of tubes, to try if this is 
the end of our quest. Unground for the first attempt, 
I hope this is sufficient.

I will keep you updated.
Wolfgang

   

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