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IBM International Model "A" Master Clock

John Lippold

NAWCC Member
Feb 2, 2011
Hello, I'm wondering if anyone has one of these International Model "A" Master Clocks, a parts manual or any other documentation about these master clocks. I'm trying to find out what the configuration of the optional Duration Contacts were and where they were mounted on the movement. Thank you,


m1-216009-(A)-07-21.jpg m1-216009-(A)-08-21.jpg m1-216009-(A)-09-21.jpg m1-216009-(A)-10-21.jpg m1-216009-(A)-11-21.jpg m1-216009-(A)-12-21.jpg m1-216009-(A)-13-21.jpg M1-216009-(A)-14-21.jpg M1-216009-(A)-15-21.jpg

John Lippold

NAWCC Member
Feb 2, 2011
Hello IBM Clock,

Thank you for posting the pdf file about the International Type "A" Master clock. On page No. 6, Fig. 2 of the document they do show a set of optional duration contacts. In my clock, that mounting bracket has two threaded screw holes with screws in them and the holes do not match the drawing in Fig. 2. This is why I was hoping to find someone with one of these clocks that has duration contacts installed.

I've seen this document before and it's interesting the Wind Contact "B" shown in Fig. 3 is different than the one used in my clock. I suspect the clock described in the document is an earlier version of the Type "A" Master Clock. The document indicates it is undated but the contact type shown in the document was used in International Master Clocks prior to 1920. I'm guessing this document was probably dated around 1919.

There is no metal Model/Serial tag on this clock and no indication there ever was one. The upper label on the back of the clock is in bad shape but I believe the serial number to be 216009 which would indicate it shipped from the factory in early 1921. The lower label has been scraped off. I do know that by 1923 this Master Clock was no longer available but was replaced by the Type "A-88", (see photo below) which is an 88 beat master which uses the more common International Master Clock Movement.

Thanks again for your timely response,


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