Seiko 7005 broken click

[Kingsie]

I’ve just started tinkering with mechanical watches and I’d appreciate help/input from the more experienced people here

 

I bought a cheap Seiko 7005 watch from eBay to experiment with. The watch was running (albeit not very accurately) when it arrived but the power reserve wasn’t good

 

I stripped down the movement to inspect the parts and prepare for cleaning

 

The first stages of the strip down were fine. I was following Seiko’s documentation and various videos on YouTube. However I became confused when I got to the stage where I needed to remove power from the movement so I could detach the ratchet wheel

 

I know that power removal involves disengaging the click from the ratchet wheel. However I discovered that the click in my 7005 had snapped and was never engaged with the wheel in the first instance. All that’s left of my click is the stepped part that slots into the base plate, the ‘arm’ of the click that actually engages with the wheel has gone. I’m guessing that the click was broken by the last person to open the case

 

This isn’t a problem per se, a replacement click for a 7005 won’t break the bank

 

My question: How come the movement could run without a click? I thought the click was crucial to the watch being wound. How could my 7005 wind itself without a click? Am I missing something here?

[aac58]

That's because the auto-winding mechanism also prevents the mainspring to unwind by itself. In fact, to unwind the MS in these watches you need to first remove the 2nd reduction wheel and then you can hold the click and unwind it.

[Randy55]

AAC58 nailed it I think

Edited June 7, 2022 by Randy55

[Kingsie]

47 minutes ago, aac58 said:

That's because the auto-winding mechanism also prevents the mainspring to unwind by itself. In fact, to unwind the MS in these watches you need to first remove the 2nd reduction wheel and then you can hold the click and unwind it.

That makes sense, thanks aac58

 

As an extension question, why does a 7005 have a click if the auto-winding mechanism also prevents the mainspring unwinding by itself?

[aac58]

1 hour ago, Kingsie said:

That makes sense, thanks aac58

 

As an extension question, why does a 7005 have a click if the auto-winding mechanism also prevents the mainspring unwinding by itself?

Because the click is designed to hold the spring and the winding mechanism is not, although it does. Probably it's standing a pressure (against the winding direction) that should be supported by the click instead, and that might affect other characteristics, for example the ability to self-wind or the wear of the pawl lever tips and the 2nd reduction wheel teeth. That could explain a poor power reserve, but here I'm just guessing.

Edited June 7, 2022 by aac58

[Kingsie]

2 hours ago, aac58 said:

Because the click is designed to hold the spring and the winding mechanism is not, although it does. Probably it's standing a pressure (against the winding direction) that should be supported by the click instead, and that might affect other characteristics, for example the ability to self-wind or the wear of the pawl lever tips and the 2nd reduction wheel teeth. That could explain a poor power reserve, but here I'm just guessing.

Logical reasoning, thanks

 

I'll give you guys a shout if I need more help with the 7005's rebuild