Master Navigation Watch

Type AN5740

Hamilton 4992B (works for 3992B too)

The Hamilton G.C.T. Service and Repair Manual

Operation, Service and Overhaul Instructions Manual

with

Parts Catalog

This manual for the 4992B movement can also be used for the 3992B movement. The only difference between these two movements is the minute and hour wheels of the 3992B movements for the conversion from 24 to 12 hours, otherwise they are identical. 

Also some of the 4992B movements have been converted to 12 hour dial after the war. There are some indications, that Hamilton offered a "conversion kit" to do this. I have one of these 4992B 12 hour dial watches myself, which is identical to a 3992B in every other perspective.

Here you can buy a PDF scanned manual and repair instructions with parts list for a Hamilton 4992B movement. It contains 36 pages with the following chapters.

Section I - Introduction

Section II - Description

Section III - Preparation for Use

Section IV - Operation

Section V - Service Inspection, Maintenance, and Lubrication

Section VI - Disassembly, Inspection, Repair, and Reassembly

Section VII - Test Procedure

Section VIII - Introduction (Parts Catalog)

Section IX - Parts Catalog with Exploded Views

Section X - Parts Catalog Numerical

The manual with repair instructions and parts list has extensive drawings and work instructions, explains maintenance and repairs in detail and even explains the adjustment specifications and how these are measured.

This manual is delivered as a PDF file via email or download. This offer only includes the manual as a file, no watch or anything else. No printed manual will be sent, but either a download link will be sent, or the manual will be sent as an email attachment if your email account allows emails with more than 18 MB of attachments and you give me your email address. For email delivery, please enter your email address in the notes to the purchase and make sure that it is correct.

YOU CAN CONVERT 12H CONVERSION 4992B BACK TO 24H VERSIONS.

HERE I DESCRIBE HOW:

 At the end of World War II there were a lot of the 4992B movements changed from a 24 hour military watch to 12 hour civilian watches. The dials were also changed to what we often see which is a 12 hour painted dial and a sweep second hand instead of the conventional second like what would be on a 992B movement, parts were available from Hamilton to make these changes.

This can be rebuilt if you have the right parts from a bad 4992B donor movement. Or if you find them individually, of course.

This is just a description, these items are not part of the offer.

So here is what has to be changed. The minute wheel, the hour wheel and minute wheel pin or arbor. The latter takes more tear down than just removing the dial.

You will notice the minute wheel is different the outside diameter and the tooth count on the wheels are the same but the little gear on it in a 24 hour watch is much smaller and has more teeth than the one of a 12 hour conversion watch. You will also see that the hour wheel on the 24 hour watch has 2 times as many teeth as the 12 hour watch.

The pin or arbor, i.e. that for the minute wheel, is much smaller. The 12 hour watch has a pin .55mm as found on any 992B movement and the 24 hour watch has a pin that is .32mm.

You will have to remove the set bridge. It is held in place by two screws that need to be removed in order to remove the minute wheel. After you remove the set bridge you will need to remove the set spring winding pinion, set gears and so on. They will fall out once you turn the movement over so it's better to go ahead and remove them before they fall away.

Next the pin or arbor has to be changed. To get the pin or arbor out you will need to get at the back side of the pillar plate in order to press it out.

Then the pin or arbor must be turned down to the height of the pillar plate to a diameter of .32 mm and is then pressed in again.

Of course, the whole thing also works the other way around if you have the parts of a 992B donor movement to turn a 24h 4992B into a 12h.

Hier die leider nötige Erklärung des Ausschlusses von Garantie und Gewährleistung, die ansonsten auch für private Verkäufe gesetzlich gilt. Ich verkaufe dieses PDF Datei Manual nur unter Ausschluss der Garantie und Gewährleistung. Irrtümer sind nicht ausgeschlossen. Die Ware wird unter Ausschluss jeglicher Gewährleistung verkauft. Alle Angaben nach besten Wissen und Gewissen. Der Ausschluss gilt nicht für Schadenersatzansprüche aus grob fahrlässiger bzw. vorsätzlicher Verletzung von Pflichten des Verkäufers sowie für jede Verletzung von Leben, Körper und Gesundheit. Ein angegebenes und angenommenes Gebot ist verbindlich. Gebots-Rücknahmen sind ausgeschlossen. Der Bieter zahlt bei Nichterfüllung des Vertrages 30% der Kaufsumme, zzgl. der dadurch entstehenden Kosten als Entschädigung. Wer mit diesen Bedingungen nicht einverstanden ist, möge bitte nicht bieten und/oder kaufen. Wer kauft, akzeptiert diese Bedingungen als Vertragsbestandteil. Rückgaben und Nachverhandlungen sind ausgeschlossen.

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