Hamilton 770 Movement Restore

[kd8tzc]

I have my grandfathers old Hamilton 770 that I would like to restore.  It runs, a little rough, so it needs a good cleaning and oiling.  I will likely also look for a parts movement just in case.

In trying to get all my ducks in a row though, one of the things I started to look into is getting a replacement mainspring lined up (not looking to buy it just yet, but know that I can get one if needed and what to order).  I took a look at the GR Database, but I don't see an entry for 770.  Did Hamilton use someone else's movement back in the 1950's and place it in there and I should be looking for something else?

Here is a picture of the face and movement side of the watch. 

Edited May 12, 2023 by kd8tzc
.

[RichardHarris123]

Here you go. 

[kd8tzc]

@RichardHarris123, forgive me Richard, but where do you see the mainspring in that?  Maybe I just don't  know how to read the information.

[mikepilk]

They are usually listed on Ranfft, but not in this case. Nothing listed in Bestfit, or on Cousins either.

You might just have to measure the existing spring - but it might be OK anyway. I used to replace most mainsprings, but now rarely do unless I really have to.

[RichardHarris123]

Sorry it doesn't give the mainspring information, I was just showing that the Hamilton 770 exists.  Unless anyone knows the spring size, you'll have to measure it.

9 minutes ago, mikepilk said:

They are usually listed on Ranfft, but not in this case. Nothing listed in Bestfit, or on Cousins either.

You might just have to measure the existing spring - but it might be OK anyway. I used to replace most mainsprings, but now rarely do unless I really have to.

Haha, we must of been typing at the same time. 

[mikepilk]

Jules Borel showing it's the same spring in 980, 923, and lists it as GR3281-T.   T-end, oh what fun 

 

[kd8tzc]

Great... another T end... how am I so lucky.  Well, I forget the amplitude that it was showing on the timegrapher, but I do recall it was low (sorry, don't have the actual numbers but will test before I start).  Maybe I will clean it all up and see what happens.

@mikepilkhow did you get that to come up?  For the life of me, I can't figure out the search feature on JB's site.  I go to the Parts Watch Database, but I can't get anything to ever come back.  I must not understand what it is looking for.

[mikepilk]

In the database http://cgi.julesborel.com/?_ga=2.99547678.1292671413.1673701735-126716363.1672876102

Select " Search for parts for manufacturers G to O"

Then select Hamilton, and scroll down to 770

[kd8tzc]

Thanks Mike... good thing those links didn't have teeth... I didn't even notice them there and was just trying to make that Case # box work.  Much easier to do it your way.