Worn pivots on a Seiko

[anilv]

I have several movements sans watches and in my free time I service them (the more popular ones at least)  so I usually have one on hand for a quick swap. I've been working on a Seiko 6309 recently, an ebay special.

This movement was marked '6349' on the auto-wind bridge but on removing this I was a bit disappointed to see that the third and fourth wheel pivots were unjeweled... this was the plain jane, vanilla 17 jewel 6309 with a 6349 autowind bridge thrown in!. Ah well, the 6309 is good enough in its own right.

or is it?......

Pegging out the holes it didn't 'feel' right, on taking a closer look the pivot-hole just didn't look right.

Looking at it from the other side and ... looks like I have a problem.

Viewed against the light..

Some serious wear! This is not typical of Seikos (in fact I can't remember coming across another Seiko with this problem) but can happen if a pivot gives way suddenly, allowing the mainspring to release all its energy at once. The wheel itself was fine but since this watch was already a 'mongrel' it could have be.en swapped out in a effort to get it running.

Well I have a bunch of 63xx movements so a replacement was soon found. In the pic below, the damaged bridge is on the right and the bad pivot is clearly visible.

The replacement bridges shows some wear on the plate where the ratchet wheel has been rubbing. There was some slight movement when I fitted the barrel so what can be done?

On these seikos, the barrel runs in a steel bushing, slight better than running in bare brass but not as good as running in a jewel. So with a suitable drift (too big for normal staking tools) the bush from the damaged bridge was removed and installed onto the replacement bridge.

One thing to note, the barrel pivot usually wears on one side, so when re-installing the bush I try to install it 180 degrees from its original orientation (use a marker for a reference).

While there was still some movement when I installed the barrel, it was markedly less than before.

Rest of the re-build is your standard Seiko.. no problems except for a wobbly rotor-bearing..

Looking at the pics while writing this post I realised that it was possible that the pivot-holes could also be steel bushes, will check this out on the damaged bridge later.

Happy weekend!

Anil

 

[Watchtime]

looks like it worked like a drill, damaging the bushing.

[ro63rto]

only ever seen that on barrel pivots.

[clockboy]

I have seen pivot holes made of steel on the real low grade pin lever movements but was not aware some Seiko Calibers also have this poor design. I think I see one of Marks vids where he reams out the centre wheel pivot hole & replaces with a jewel. A while ago I did replace a barrel arbour bushing. I had to make the bushing out of brass because although conventional jewels had the correct internal & external dimensions they where all to thick.  This is a very interesting vid that shows the method I used.

 

[oldhippy]

I can remember, yes I can remember some old Seiko's where the center top pivot wasn't jeweled. 

[rogart63]

Barrel arbor bushing do very often have that wear? If i can find a better one from an other movement i use my staking tool to replace it? The 6349 auto.winding bridge probably had a better bearing then the old 6309 had. 

Usually is a lot of different parts in the old 6309 watches. As NOS parts are hard to find.