Worn barrel bushing

[ddrescueb2048]

I am learning watch repair and am working on my first 'broken' movement, a seiko 7009a, with a wheel train does not move freely when the bridge is fully tightened.  The first thing I noticed is there is wear on top of the bridge where it appears that the ratchet wheel has been rubbing.  I traced the problem down to where the barrel meets the center wheel.  I gave a close inspection and saw that the barrel bushing on the bridge appears to be worn.  My thought is that this allows too much side shake and is potentially binding the gears at this point.

My question is does this diagnosis sound correct?  If so, is my only option either to find a replacement bridge or find a way to replace the bushing with a jewel?  I have been wanting to learn how to use a jeweling tool but suspect this would be a poor choice for a beginner to learn on.  Any advice is appreciated; thanks!

 

[szbalogh]

That bushing seems ok from here, its not oval. 

I have a Stowa with ETA movement and had a similar strange problem. The bushing was ok but there were terrible marks on the bridge, like here. The problem was that the bridge was not tightened fully, and the barrel pinion was not sitting in the bush all the way down making the barrel not sitting upright. 

Your 3rd picture shows that the barrel arbor was not all the way down in the bushing. 

[rogart63]

The bushing in the train wheel bridge or auto device plate  is worn. You can actually see that it's oval. Either you find a better bridge or replace the bushing with a better one from a scrap movement. Think the 7s26 movement has the same bridge? 

A fix could be to rotate the bushing a 1/4 turn. That could work. But it's better to replace. 

Haven't seen any jewels that fit this movement. 

Edited August 5, 2017 by rogart63

[anilv]

Seikos will usually run with a worn barrel bushing.. not well but it usually runs well enough for my Indian cousins to flog them on eb@y 

With the barrel and train installed but not the ratchet wheel and escapement, push on the barrel teeth and see if the train wheel spins well.

One thing on these movements is the screw post is also the centre seconds lower pivot. Applying force when undoing the rotor could lower the pivot (its pressed in) and cause the train to bind when you tighten bridge.

Try installing the bridge without the barrel and see if the wheels are free.

All the best!

Anilv

[anilv]

 

Edit

...... is the screw post for the automatic weight is also....

sorry!

[ddrescueb2048]

I'll answer the questions first:

1) Is the arbor all the way in the bushing?

I believe it is but have included a picture of the top and bottom pivots.

2) Does the wheel train spin easily with the bridge tightened all the way and the barrel removed?  What about the barrel without the wheels?

All the gears spin easily and when I check the movement of the pivots in their jewels things look about right.  When I install the barrel without the wheels and tighten the bridge all the way the barrel moves easily.

 

I was able to get a picture of the kind of movement that I am referring to by side shake of the arbor pivots:

 

I am currently not equipped to replace a bushing but am eager to change that.  Would a Seitz complete set off ebay and the assorted barrel bushing pack on cousinsuk cover the tools and materials required?  Obviously there would need to be some book learning and some followup study to determine the correct technique to apply.

[ddrescueb2048]

I just realized that I have a 7016 movement which looks to have the same bushing and it isn't worn looking like the one pictured above.  Would I be able to simply remove that bushing with a Seitz tool and swap it?

[anilv]

They are the same 'base' caliber but chronos usually have different mainsprings due to different power requirements. No harm trying!

Also you can try to re-orient the current bush 180degrees like has been mentioned earlier. The bush can also be lowered it its bridge but not too much.

Anilv

[ddrescueb2048]

Thanks for the advice everyone.  I'll have to move this project into the queue until I acquire the tool but I'll follow up in this thread with the results in the next few weeks.  It is good to know that I am on the right track so far.  Thanks again!

[ddrescueb2048]

Just to follow up on this project...

I received my Seitz tool and had some time to continue work on this.  I decided to start simple first and rotated the bushing 90 degrees but that did not make any difference.  Next I ended up applying a decent bit of pressure on the bushing with a flat pusher while it was in the bridge and think i may have succeeded in closing the hole a bit because the arbor would not fit anymore.  I ran the closest sized reamer through and ended up with less shake of the arbor once this was done but the problem was not fixed.  

 

What it turned out to be was anilv's suggestion to check the screw post for the automatic weight.  I was looking at it from an angle and noticed it was slightly protruding from the bottom of the bridge.  I pressed it back out very slightly and the problem is now resolved.

 

Thanks, anilv, for that suggestion; it was spot on!