One might also consider mounting smaller items inside the cylinders of the engine block, to get the most out of its thermal mass.
Dana On Thu, Sep 9, 2021 at 11:03 AM Joseph Gwinn <[email protected]> wrote: > On Thu, 09 Sep 2021 03:30:35 -0400, [email protected] > wrote: > Re: time-nuts Digest, Vol 209, Issue 6 > > > > ------------------------------ > > > Date: Wed, 8 Sep 2021 18:54:03 -0700 > > From: Tom Van Baak <[email protected]> > > Subject: [time-nuts] in-ground clock room > > To: Discussion of precise time and frequency measurement > > <[email protected]> > > Message-ID: <[email protected]> > > Content-Type: text/plain; charset=utf-8; format=flowed > > > > I am considering a below ground "clock room" away from the house. This > > will be for some low-drift quartz oscillators and also a couple of > > precision pendulum clocks. The goal is long-term, unattended, and very > > undisturbed operation. > > > > For scale, assume the room is 1 meter × 1 meter × 2 meters deep. So > > that's vastly smaller than digging a basement, but much larger than > > drilling a 8 inch round pipe. Digging down gives some natural isolation > > and temperature regulation. A couple tons of concrete gives high > > stability vertical walls for the pendulum clocks. > > > > If any of you have personal or professional experience with the design > > or construction of this sort of thing, especially experience with > > precast (utility) vaults or poured concrete, please let me know. > > > > In case this gets too off-topic for time-nuts, off-list email to me is > > fine ([email protected]). > > As others have said, it may not be economically practical to build an > underground clock room. > > Assuming that you have a basement of other suitable room in your > house, I'd suggest an insulated box or room containing a big lump of > iron riding on an inner-tube suspension of some kind. The big lump > of iron can be a 500-pound truck engine head or block from a > junkyard, steam cleaned (to remove oil) and painted (to keep the rust > under control). Drill and tap holes as needed for mounting. > > This box/room plus block can be set up as a temperature-controlled > oven with a few extra components, including a PID controller. > > Bolt a thick plywood floor to the top of the iron hunk, and attach > the clocks to this floor. > > Joe Gwinn > _______________________________________________ > time-nuts mailing list -- [email protected] -- To unsubscribe send > an email to [email protected] > To unsubscribe, go to and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] -- To unsubscribe send an email to [email protected] To unsubscribe, go to and follow the instructions there.
