IBM Industrial Master Clock

[Tmuir]

At my watch and clock association BBQ I picked up for a song this IBM master clock along with the case, pendulum and slave dial of a Synchronome clock.

The Synchronome clock has just been stored away as it is missing too much to do anything with it, but this IBM clock is pretty much complete.

I've not finished my reserach on it, but from what I can see the clock is powered by a mainspring and the mainspring is would by electromagnets.

It would appear the power is used just to wind the clock and provide signals to other slave clocks.

The clock is complete except for the missing second hand and the pendulum rod is bent which will be fun to deal with.

It has a sticker on it stating it was installed in 1962 and the plat of the clock states it is a model 41572ZZ , but I can't find any infor on that model.

If anyone can provide any more information please do.

The clock is so 'chunky' and 'industrial', I could even stretch to 'ugly', but I love it.

Anyhow enjoy the photos and yes it is big, I haven't measured it but it comes up to just below my shoulder.

[AndyHull]

Big Blue did more than just make computers and typewriters it seems.

Furthermore there is a fair amount of info, if you peer in to the correct corners of the internet.

https://www.ibm.com/ibm/history/exhibits/cc/cc_room.html

 

[AndyHull]

Yours appears to be a derivative of the "type 25"

https://www.ibm.com/ibm/history/exhibits/cc/pdf/cc_2407M251.pdf

[AndyHull]

It reminds me of the sort of thing you would have seen in some of the big factories I visited over the years. I'd place it somewhere between the late 50s and the late seventies.

 

These things were the bane of the tardy worker, as they were linked to the clocking in system.

If you clocked in 5 mins late you were docked 1/2hrs pay, up to 15 mins and you lost an hour, and anything more and you were hauled up before the manager.

[Tmuir]

Thanks for the link.

Yes I also have a National Time Recorder desktop model. Rather than putting your card in you cranked a handle and it stamped the date and time and you signed your name next to it.

Pretty sure mine is from the early 60s. I've downloaded a service sheet and will read and digest that over the next few days.

[AndyHull]

The important question is.. does it go.

The next most important question is.. what is the piece of paper wedged between the contacts of the middle switch in the mechanism shot doing, does it allow you an extra 15 minutes in your bed each morning

[oldhippy]

This is one type of clock movement I never worked on. I do not intend to start now. I am no electrician.

[Tmuir]

It actually has a couple of the relays wedged out and have just noticed it is missing a spring from the middle relay stack like is on the bottom relay stack, but that is easy enough to replace.

My plan is to disconnect the mains supply and leave it inside the clock as its part of the original build and use a modern power supply to just supply what is needed to operate the coils for winding.

As part of my apprenticeship in telecommunications I did many years ago I was taught how to adjust relays and a few years back purchased a toolkit for adjusting relays for working on a 1978 Chicago coin pinball machine, so the 3 relays on the side of the clock do not worry me, unlike the stack of Selenium rectifiers below the transformers which provided the DC voltage from the transformer. No way I am connecting that to the mains.

[AndyHull]

Selenium rectifiers certainly show its age, at lease they aren't mercury tube rectifiers, although those do emit a nice glow.

You might like this series ...

.. nothing much to do with clocks or watches, but lots of stuff about contemporary vintage equipment.

[AndyHull]

You could of course replace the selenium rectifiers with modern silicone diodes, if they are shot (which they probably are not). Any ancient capacitors would be more of a worry, depending on what construction they employ.

[Lenj]

Love that old 50's photo, that brings back some memories..

 

[LH97]

G’day,

As of today, I picked up an exact copy of your IBM clock in a hard rubbish pile. I couldn’t fathom the origin nor what it was used for other than time keeping. I happened to stubble across a photo of your clock on Google!

[AndyHull]

3 hours ago, LH97 said:

As of today, I picked up an exact copy of your IBM clock in a hard rubbish pile.

Have you got any pictures of it you can share?

[AndyHull]

I was just re-reading the PDF about these clocks and spotted that they were actually comparable in accuracy to a modern mass produced quartz clock.

Quote

INTERNATIONAL MASTER CLOCK, self regulating magnet wound spring driven
movement. Several hours reserve power with current shut off, fully rewinding on restoration of
current supply, winding spring wound to same tension to prevent overwinding and insuring good
time keeping. 60 beat, Graham dead beat escapement with micrometer adjustment. Furnished
with Metal Ball, (Invar) or (Mercurial) pendulum. Time rating plus or minus per month with
Metal Ball pendulum 30 seconds, (Invaró15 seconds) (Mercurial pendulumó10 seconds).
Precision cut gear train of hard brass, burnished and plated. Pinions of stainless steel machine cut
and burnished. Furnished only with dial as shown.

30 seconds a month if my memory serves, is a typical accuracy for a typical quartz movement. Obviously better tuned crystals, and better temperature control will produce much better accuracy from a quartz oscillator, but a run of the mill 32768 Hz sits around this level.

Not bad for a purely mechanical movement.

Edited October 27, 2023 by AndyHull

[LH97]

G’day, 

I finally got around to taking photos of the clock. When I picked it up, it was intact. I have removed the case to get a better understanding of its workings. It’s currently laying on the floor in the downstairs spare room.

It’s definitely a keeper!

 

The case itself needs repairing. It was nailed shut which took some prying to open it.
 

I’m assuming it had a bracket attached to the case which may have been used to then attach to a wall.

Please note that the paperwork in the last picture was found inside the case. It’s barely legible but adds to the history.

Cheers

[AndyHull]

Very nice. I presume the kink in the pendulum rod is not factory correct.
Is the weight  the Invar version, or mercury filled?

"Time rating plus or minus per month with Metal Ball pendulum 30 seconds, (Invar 15 seconds) (Mercurial pendulum 10 seconds)."