[time-nuts] Oscilloquartz 8601 Rebuild Question
ed_palmer at sasktel.net
Mon Aug 1 18:21:57 UTC 2011
I did find Pope's site earlier after looking for Dewar flasks on eBay.
They don't have one that's close enough in size to be worth the cost
premium over a standard Thermos bottle. Same with a Google search for
other Dewar suppliers.
The original Dewar had internal dimensions of approx. 50 mm in diameter
by 100 mm deep. My three candidate bottles so far are two glass ones
with internal diameters of 80 mm and depths of 105 mm or 160 mm and a
steel bottle with a diameter of 75 mm and a depth of 130 mm.
Although the short glass bottle seems like it would be a good fit, it's
internal depth limits the thickness of the foam plug that I can use.
Either the diameter (larger than the original) is allowing more heat to
leak through the foam or my foam isn't as good as the original. The
result is current readings about 10% higher than the spec. The taller
glass bottle gives me lots of room for a plug. I can get current
readings 10% lower than the spec, but it's so tall that it's awkward to
use. The steel bottle has better dimensions, but the current is 15%
higher than the spec. These numbers might be close enough that it
doesn't matter. I'm leaning towards the steel bottle because of it's
strength, electrical shielding, and since I was able to retain the
screw-on cap, it has a more secure method of holding the foam plug in
place. But I haven't ruled out the short glass bottle yet.
On 8/1/2011 9:38 AM, J. Forster wrote:
Maybe these guys have what you need:
John & Don,
Thanks for your thoughts and ideas. Limited availability of different
sizes and shapes of vacuum bottle is a problem, but I'll be keeping
your ideas in mind when I make my selection.
On 7/30/2011 6:29 PM, J. Forster wrote:
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