Hard to spot wear/damage.

[fjseal]

Reassembling an FHF 96-4 movement, I was gratified (in the usual self-satisfied way!) when the balance went in and it started up. However, it would only run dial side up, and as soon as I turned the watch over, it stopped. It took a while to fathom it out, but I closely inspected the balance pivots and discovered the lower one was worn. This was the best photo of several that I took and it is not very easy to discern the wear on the pivot. It is the left-hand one in the picture. For me it is a reminder to carefully examine these type of components as I am disassembling the watch. Hope this is of interest to others. Luckily, I have a balance wheel from another movement, and that has cured the problem.

Edited December 7, 2017 by fjseal
Last sentence added.

[oldhippy]

It is good practise always closely examine every part. Try to remember this with every repair, it will soon come naturally.

[jdm]

10 hours ago, fjseal said:

 This was the best photo of several that I took and it is not very easy to discern the wear on the pivot.

For more detailed pictures just place the eyeglass on camera or phone lens. Works very good.

[fjseal]

Oldhippy, as a retired aircraft fitter it should come naturally allready, tsk...tsk!

Jdm, my digital camera is good at closeups, but I must try your suggestion sometime.

[anilv]

On 12/8/2017 at 4:04 PM, oldhippy said:

It is good practise always closely examine every part. Try to remember this with every repair, it will soon come naturally.

 

To add on Oldhippy's excellet advice... you need to inspect each parts function as you dismantle the watch. ..

As an example...when removing the crown, check if the crown works as it should. Also set the hands to see if all is ok and that the cannon pinion has proper friction. If you skip this step you may find that when you refit the cannon pinion needs tightening or the watch doesn't set because the setting (keyless) mechanism is worn.

I have kicked myself a few times over stuff I should've caught earlier... usually its due to overconfidence. Sometimes it may be because you already think you have identified the problem but there may still be others. I have several watches in my stash from which I have robbed parts,  one Tissot 781 has sacrificed its barrel, balance and centre seconds pinion. The scavanged parts have been replaced by the faulty one because I felt it would be handy to have something to compare with if I need to rebuild this movement. The next guy to work on this (when I'm gone) will probably catch the barrel and balance but he may only notice the faulty seconds pinion only after the watch is fully assembled.

Anilv