First 6138 Seiko Chronograph

[thor447]

Tonight I was finally able to spend some time at my bench and put my 6138A Seiko dual register chronograph back together.  This is from a 6138-0010 (UFO) that I picked up a few months ago.  The movement was originally covered in oil, spots of rust, and looked terrible.  It cleaned up pretty well.  I replaced the mainspring, replaced the upper barrel arbor bushing with a jewel, and replaced a broken hour fly-back lever.  This was my most ambitious attempt yet, and I'm really glad the nights of watching videos, and studying the service manual cover to cover about 5 times paid off.  This movement went back together really well and is now running in for the next 24 hours before making any further adjustments.

 

Before:

After:

 

 

Edited January 1, 2023 by thor447

[JohnFrum]

Congratulations. 
I presume reaming out the bushing was quite challenging? Off centre wear on the bushing?

Edited January 1, 2023 by JohnFrum

[thor447]

Just now, JohnFrum said:

Congratulations. 
I imagine reaming out the bushing was quite challenging? 

On the 6138 the lower arbor is already jeweled. The upper arbor port in the barrel bridge is just a bushing that can be pushed out and directly replaced with a jewel without reaming.   On the 6139, both upper and lower’ arbor ports are bushings. The lower would have to be reamed, but if you have a 6 mm OD stump, that is the perfect size to sit in the recess on the main plate so that it doesn’t move while you are reaming it out. I actually have one of those on the way from VTA for a 6139-6005 Pogue that will be serviced soon. 

[thor447]

I finished work on the 6138-0010.  I decided against re-luming or doing any case work. Just keeping it as original as possible.

It didn't come with a bracelet so I found a close remake of the original.