Hi Scott,
For what it’s worth, cryofab calls that piece a “quick coupling
nut.” But as far as I can tell they’ve only got 4 sizes available
and I’d be pretty surprised if any of those fit your needs. I did a bit
of googling and found that there are similar parts available but everything I
found would require modification—usually an extra hole drilled in the end.
It’s a fairly simple part—you might ask your machinist if they
can make you one. I was trying to 3d print one and consulted with our machinist
and he said that he could easily make one. I don’t need one because all
our magnets are normal sizes… but if I did need one that’s the
route I would take.
And just because I was curious I 3d printed something that I think might work and
then used a tap to cut the threads (wrong size threads because I didn’t have
the right tap…) and I’m now going to go dunk it in LN2 to see how
well it handles low temperatures. I did make it a bit beefier than the aluminum
nuts that are on magnets because I guess the 3d printed parts tend to delaminate
under stress. Maybe making it bigger will reduce that possibility…
Cheers,
Mike
> From: main_at_ammrl.groups.io <main_at_ammrl.groups.io> On Behalf Of Scott Burt
> Sent: Thursday, August 31, 2023 10:27 AM
> To: main_at_ammrl.groups.io
> Subject: [AMMRL] Finding Replacement Open Top Screw Caps
This feels like a very silly thing to ask, but I have had absolutely no luck
with my web searching skills on this.
One of my colleagues has an old horizontal bore FTICR magnet and the open top
screw cap that holds the plug in place on the LHe port is just slightly bigger
than the Oxford screw caps I have lying around. The thru hole is the same
(i.e., fits a 3/8" transfer line), but the diameter of the threaded walls is
something like 1 mm wider than the oxford screw caps that I have on my old
R2D2 magnet and my round-bottom 500.
These can clearly be purchased in various sizes as I have similar caps with
different dimensions from my Magnex magnet. I was expecting to find these
at McMaster-Carr or similar places, but I'm obviously not using the correct
name for these. "open top screw cap," "metal screw cap with thru hole,"
"liquid He port assembly" and other possibilities hasn't turned up anything.
The closest I've found is spark plug retaining caps, but there doesn't seem
to be a lot of variation in dimensions for those...
If anyone has any tips on where to purchase these in various sizes so I can
try to find one the correct size for this old magnet, it would be much app
reciated.
-Scott
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Received on Fri Sep 01 2023 - 14:32:11 MST