So now the 3rd and final segment in the repair of my Brother-in-law's Bulova.
While I'm checking the watch for timekeeping, the case needs some attention. Now since the case is gold filled, I can't do any really aggressive polishing on it. However I can remove some of the tarnished look it has:
So I use some diamantine powder, mixed with a little mineral oil, and use a piece of peg wood cut on and angle as a buffing stick.
After a little bit of work, the case looks much brighter.
Although this method can't remove big scratches, it can remove the haze that sometimes happens on gold pieces. Here is a shot of a Hamilton watch from the 1940's I just finishing restoring, and you can see I've completed 1/2 of the case back, and removed a lot of haze made up of very fine scratches.
So with that done, time to change the crystal since the old one is beat up pretty well. Here are the old and new crystals side by side.
Now this is an acrylic crystal, and held in place with a tension ring. Basically it's a brass ring on the inside of the crystal that provides an outward force on the crystal so that it fits snugly into the case. I use my crystal/case back press for this operation. Correct sizing of the new crystal is critical, and they come in 0.1mm increments.
I place the case in the press, then the crystal on top, and screw down the handle.
The loud snap tells me the crystal has seated. Looks much better!
Now the movement goes into the case. But first I lubricate the stem with stem grease.
Then the movement ring is placed on the movement, and the whole lot if dropped into the case. Note the lugs on the movement ring. These are used to secure the movement from flopping around in the case. The lugs are bent upwards, and when the back is screwed on, the back compresses the lugs and secures the movement - simple, but effective. The back is ready to go on after some silicone grease on the gasket.
Will look nice with a decent strap - I mocked it up with the brown Di-Modell off my Sinn just to see what it will be like.
I'm sure my Brother-in-law will be thrilled with this for his 50th birthday.
BTW the watch is running quite well. Here is the calculation for the Mean Average Daily Rate:
Dial up average daily rate = +2
Crown Right average daily rate = +8
Crown Down average daily rate = -15
Mean Average Daily Rate = +2+8-15 = -5/3 days = -1.67 seconds per day.
I could keep tweaking it but really it will depend on how the watch is worn, but for an unadjusted watch this is a great result! I wish they all came out this well!
Again, thanks for all your interest in these posts.
A true friend stabs you in the front.