Fused quartz pendulum ror


Thank you  for that very interesting article john. David cements a short price of invar inside the FQ pendulum , and uses that to support the temp compensator under the bob, which is a great idea and one that i will look at. I have plenty of invar and it is about the correct size i think. I will check tomorrow. The TC of the epoxy will still tend to change the pendulum length, but i guess it will be a small amount, and can be compensated for with the under bob compensator. Trying to model the effect of the epoxy joint is giving me a headache, so i need to give it more thought.
I will report back.

On Sat, 4 Apr 2020, 9:36 PM John Haine <john.haine@...> wrote:
Ni Neil, David Walter uses FQ rods in his (D)W5 clock.  This pdf from the HJ may be useful.

John Haine

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 Haine

Neil, further to your question, I was leafing through my copy of "Woodward on Time" to chase another reference and it includes a short description by David Walter of how he went about the construction, giving more detail than his website.  It wasn't published separately alas (I think).  But he specifically refers to "...using a special Loctite adhesive designed to bond metal and glass."  That might help?