Hi everyone,
This is my first post and have a couple of questions. I'm just learning about the wonders of mechanical watches and managed to purchase a Hamilton 974 movement. What a beauty. I am in the process of disassembling this movement and unfortunately the screw for the ratchet wheel must have reached escape velocity and is now orbiting the earth somewhere because I cannot find it anywhere. I saw that Cas Ker has an assortment of screws (Swiss made)on their website. Will these work on an American made watch? Is the thread pitch common to all pocket watches regardless of being American or Swiss made? Second question: Where can one obtain a parts breakdown (pictorial) of this movement? Thanks in advance for any help.
David

Welcome aboard to IHC185 David!

I'm not a watch mechanic, so I can't help you with your present difficulty, but a lot of our members are knowledgeable in that department, so I'm sure you'll get help soon.

Ed,
Thanks for the warm welcome. I'm excited about getting my hands on something mechanical after working 30+ years as an electrical engineer. Always loved working with my hands and am especially fascinated that given the technology available in the early 1900's that a watch of this beauty could be made.
David

Welcome to IHC185 David,

It is very unlikely the screw you’re looking for can be found in a Swiss assortment. Not only are the threads all different pitches they’re different sizes and lengths as well as the OD, depth and finish of the screw head. The screw you need is a Hamilton part # 503 which was used on grades 956, 964, 965, 968, 969, 974, 975, 976, 977, and 978 according to the old material catalog I have. The new number is 521040 and the newer catalog lists it fitting all the 16 size grades except the 992B and 950B so there may be some difference in the finish (flat vs. beveled etc.) but any Hamilton 16 size ratchet wheel screw should work except the “B” models. The screw is rather large relatively speaking so if you keep looking you’ll probably find it. A vacuum cleaner with a new bag is a good way to find lost parts.

A pictorial parts breakdown for your specific movement may be difficult to find. The 974 was made in pendant set and lever set so there’s going to be different parts for each. Some parts also changed throughout the years so the serial number is needed to look up part numbers. Early models were single roller and later changed to double rollers so again different parts for different years. I have an early and later Hamilton watch material catalog used to determine which part is needed for a specific application.

Below are some links with pictorials that should be able to assist you in naming or describing a specific part.

The TimeZone glossary of watch parts

John D. Duvall's "HELPING HAND TUTORIALS" Components of a Pocket Watch

TM 9-1575 War Department Technical Manual

RR

Richard,
Thanks for all the great information. So it sounds like I'll just have to get a part from a donor movement. I did a very thorough search including using a vacuum cleaner with a new bag and came up with nothing.

Can you tell me what publication you used to arrive at the part number for this movement?

One last question: What are the chances that I can successfully make a screw for this location? I assume the part number also states the pitch and diameter of the threads? Is there a die available somewhere for me to attempt this? I do have a few lathes at my disposal ( Myford, Schaublin ) so this isn't totally out of the question.
Regards,
David

David,

The older catalog is from 1951 and titled Hamilton Watch Materials. The newer Parts Catalog from 1961 is in PDF form but I don’t think the link for it is still working here so I’ll try to e-mail it to you.

I am sure it’s possible to make the screw but much easier to get a used one. The Hamilton catalogs do not list screw specifications.

There is a "WANTED TO BUY OR TRADE" HOROLOGICAL ITEMS section in the 185 trading mart where us members help each other find items. Just click on the link above and start a new topic with your request. It’s best to include as much information as possible and also post a picture or describe the screw you’re looking for because like I mentioned earlier there may be different finishes on the screw head and you’ll want to get one that matches the rest of the movement.

Good luck,

RR

Hamilton Watch Materials, 1951

David I have one send me your address and I will send to you. Regards Roger

Roger,
Thank you very much for the generous offer. Just sent you an email with the information.

Regards,
David

David in the mail.

Roger,
Thank you, thank you, thank you.
David

hi David; I think you will find that a spring cable handled magnet such as mine is as good a tool as you can find for locating lost screws,the handle is curled for purposes of the photo, and they are very reasonably priced,best wishes, Tom

Tom,
Thanks very much for the suggestion and the photo. I have never seen anything like that. Do you recall where you acquired that?
Regards,

Roger,
Got the part in the mail. Thanks very much. I'm back in business.

Just to be safe, I practiced taking apart and putting together some not-so-valuable watches over the weekend so that I can handle those tiny screws a little better and hopefully not lose another one.

Regards,

Check the selection of magnets at the auto parts store.

I broke the screw holding the crown wheel in my 974 movement. I thought it was a right hand thread but now I'm not sure. I have two questions:

1. Is this a right hand thread or a left hand thread?

2. How would one go about removing a broken screw from the main plate? I do have a few carbide drill bits and have successfully drilled my first hole in this screw. My plan is make an "easy out" but I'm open to suggestions.

Thanks,

Lindell,
Thanks for the reply. Yes, it is indeed a left hand screw. I did manage to get it out by drilling a hole into it with a carbide drill bit. I used the tip of an exacto blade is an "easy out" and she came right out with a little clockwise persuasion. Now I'm on a mission to get a replacement screw for this location.

Being a left hand thread is going to make it a bit of a challenge.