Pradeep Sarin

Looks like this parts watches auction has a 1677 movement with tri-shock spring protection on the cap jewel :

https://www.ebay.com/itm/WALTHAM-Vintage-Used-Winding-Watch-movement-For-parts-Replacement-Varieties/174081741810?hash=item28881493f2:g:n3wAAOSwU~Ves1OV#shpCntId

What are the chances of the 1677 balance jewel being a close match to the FHF76 ?

Thanks all, for all the info.  

Now I vaguely recall  Chris @ Watertown watch said that some of the FHF76 movements put in Waltham watches during and just after the war had tri-shock protection due to shortage of Incabloc parts.

So now I know I have a particularly hard to fix watch with hard to find parts. Will have to wait till the antique shops around here in Bombay open up - then I will have to go hunt for a matching jewel. 
If it's approximately the right size I have all the diamond nano-machining tools in my lab to polish it to shape. 

Any tips on how to find the exact dimensions required?

No it's a Waltham Wrist Watch (photos attached below). The other side of the balance wheel shaft on the back is also set in a similar 3-prong jewel. 

Update - after struggling with this off and on, in the middle of coping with life in a lockdown.... havnt made any progress.

The balance wheel jewel I have (I'm sure it fell out of the watch movement during disassembly) has 3 prongs on its chaton. (Pic below). 

It doesn't match the balance wheel jewel and chaton 3+4  in Ado123's top down diagram above.

AND I'm missing the shock resistant retaining spring + capstone jewel. Any ideas on how this assembly goes back to together?

Chris Carey at Watertown Watch Repair Co serviced the watch for me soon after my wife gifted it to me for my 35th.. 

We lived in Cambridge back then.

Now in hot, humid India - it's only needed a strap replacement in the last 12 years or so.

And now this catastrophe just at a time and a place where I can't get any parts..

Thanks for the detailed tips! This the perfect thing to occupy my time while we're locked down at home... Will try re-seating the jewels very very carefully. 

Watch: Waltham wrist watch from about 1950's.

Used to work fine.  Opened it up to clean the crystal from the inside and the dial. Now the problems are:

1: Runs face up, but not face down (the hands are off, so its not the hands sticking.

2: One jewel fell out - can't figure out where its from!

3: Examined the balance wheel motion under a microscope (when its running facing up. A slight wobble is noticed. 
     Video is posted at: Link to video of waltham wrist watch balance wheel wobble (watch face side)

     Zoomed in video at: Zoomed in view of balance wheel axle wobble

4: Is this wobble normal? Is there a jewel supposed to go in there, holding the pivot in place? 

 5:  For comparison, here's a view of the balance wheel axle from the back side of the watch, where there is a jewel in place:

    balance wheel axle from back side of the watch

And here's a  zoomed picture of the the jewel that fell out: it's 1mm diameter, and has a 3 pronged sleeve around it:

dropped jewel

Questions:

1:  is the balance wheel axle wobble normal?

2: Where does the jewel go back in?

I am a first time poster to this forum, so please be gentle. Have a liking for old mechanical watches (and old things in general). I do have access to fairly sophisticated workshop facility in my lab, so I can make whatever tools are required to press-fit jewels etc.