Hand fit fatigue?

[TedRzad]

Hello all,

 

I’ve been furiously modding and re-modding Seiko-based timekeepers over the last several months.

 

I’m chasing aesthetic experiments swapping handsets and dials zeroing in on my own ‘grammar of design’ while making much-needed improvements to my technical skills.

 

Two different dial/handset swaps I performed this week appear to suffer from what I theorize are fatigued handsets: the hour hand on each appear properly seated on the arbor but can slip with only a gentle knock to the side of the case.

 

Is there a ‘rule of thumb’ for how many times hands may be removed and re-pressed? Each of these handsets have been pressed 3 or 4 times so far.

 

Is there something in my technique that could have contributed? I use a plastic protection sheet over the hands and the symmetric hand pulling tool. I see no cosmetic damage.

 

Is there a way to gently improve the friction capacity or are the hands toast? I am an experienced bicycle, motorcycle, and car mechanic but am having trouble imagining a shim or knurling solution here.

 

Many thanks!

 

Ted

 

 

Sent from my iPad using Tapatalk

[watchweasol]

Hi   Watch hands are usually only fitted once when new and when repairs are done, constant fitting and re fitting can stress the boss closing is possible but not always sucessfull . not something I would do myself.  Not all seiko canon pinnions and hour wheels are the same size, close maybe, check the part numbers for the models you are using against the tech sheets.

[jdm]

11 hours ago, watchweasol said:

Not all seiko canon pinnions and hour wheels are the same size, close maybe, check the part numbers for the models you are using against the tech sheets.

The Seiko used for modifications all have the same hands sizes. Holes can be closed a little, either using a tool for the purpose or other techniques.

[TedRzad]

So far I’m only messing about w/ 7S26 and NH36a. I have assumed the hand sizes are identical but it’s a good in the “belt & suspenders” mode of diligence!

As far as tightening the openings of the hands goes: any tips? Is it as simple as gently cold-setting the flange inward?


Sent from my iPhone using Tapatalk

[jdm]

16 minutes ago, TedRzad said:

So far I’m only messing about w/ 7S26 and NH36a. I have assumed the hand sizes are identical 

Yes, they all are as well for the 4R, 6R, and others.

To avoid duplicated discussions I suggest you use the search function with a couple of keywords. 

Edited April 20, 2019 by jdm

[TedRzad]

Yes, they all are as well for the 4R, 6R, and others.
To avoid duplicated discussions I suggest you use the search function with a couple of keywords. 

Thanks, jdm

I did search for ‘hand fit’ prior ting this thread. Can you suggest a more precise terminology?




Sent from my iPad using Tapatalk

[jdm]

2 minutes ago, TedRzad said:

I did search for ‘hand fit’ prior ting this thread. Can you suggest a more precise terminology?

 

Loose hand maybe. Anyway what is done it to use an hollow,  rounded staking punch to close the ring. You could  try making one from a wood stick, pegwood or so.