Re: Fused quartz pendulum - temperature coef


neil
 

Matthys in his book "accurate Clock Pendulums" provides the following:

Pendulum Materials:
F Quartz                       0.55 x 10-6
Regular Invar             1.5 x 10-6
Super Invar                 0.63 x 10-6
Carbon Fibre             <0.5 x 10-6 but the glue is 5.0 x 10-6
Steel                           10.5 x 10-6
Walnut                         6.6 x 10-6   + bad moisture effects
Beech                          2.6 x 10-6   + bad moisture effects

Suspension Materials
Stainless steel              10.8       bad strength properties
NiSpan                            7.6 - 8.1   good
Berylium copper            17.5        good
Phosphor Bronze          17.8        good
Al Si bronze                 18              best
Si Bronze                          18         some thermal hysteresis
Ni Sn Bronze                 18.5         bad termal hysteresis

                        
Neil 
On 5/04/2020 12:19 am, John Haine wrote:

I'm glad it's useful Neil.  As a matter of interest, what is the tempco of fused silica, how does it compare with carbon fibre?

John.

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