Let me try this again - question about two center wheels and where the hands attach to the cannon pinion and inner shaft

[RobBrandywine]

The Seiko I'm working on appears to have two center wheels.  The 2nd wheel closer to the main plate and the 4th wheel on top of it. So are the shafts of both of these going through the main plate  (I don't see how) or just the 4th wheel?  Second question, there are 3 hands attached to the cannon pinion and shaft inside it But to work they must have 3 different sources providing rotational movement.  I believe the 4th wheel shaft is what the seconds hand is fitted over the end of.  One of the other hands could be fitted over the cannon pinion (which one?).  But what is the 3rd hand residing on?  TIA.

[nevenbekriev]

15 minutes ago, RobBrandywine said:

The Seiko I'm working on ...

Well, dissassemble this Seiko and see how it is built. Then come again and try to explain here

[mikepilk]

1 hour ago, RobBrandywine said:

The Seiko I'm working on 

What is the movement number? We cannot help if we don't know what it looks like.

[RobBrandywine]

Here's a video of a 7s26 being disassembled.  At  8:50 you can see him removing the 4th wheel which is clearly centered over the 2nd wheel.

 

The Watch Repair Channel

Here is the disassembly of a Seiko NH36.  Pretty much the same. At 12:15.

Macro Time

 

I suspect, from trying to see, that the 2nd wheel, although centered, doesn't extend through the main plate.  It's pinion gear (between it and the 4th wheel) merely drives the 3rd wheel and the 3rd wheel's pinion gear drives the 4th wheel.

Here is a Seiko 6r15 being assembled.  At 24:45 he is lowering a bridge onto the 2nd wheel.  You can see the jeweled pivot hole for the 4th wheel being placed over the center of the 2nd wheel.

Macro Time

And here is a Seiko 6309A being disassembled.  Same thing, the 4th wheel is centered over the 2nd wheel and it's shaft is what is turning the seconds hand (I think).  At 8:03.

My Retro Watches

And once more.  Here's a Seiko 7009 disassembly.  At 20:18 he removes the 4th wheel from its position over the center of the 2nd wheel.  It's apparent this arrangement has been used by Seiko for quite a while. 

Dumas Watch Repair 

And once more.  Here's a Seiko 7009 disassembly.  At 20:18 he removes the 4th wheel from its position over the center of the 2nd wheel.  It's apparent this arrangement has been used by Seiko for quite a while. 

Dumas Watch Repair 

And finally a 1972 Seiko 6105 predecessor of the 6309.  At 16:23.

Blair Witch Project

[eccentric59]

Technically, maybe. I suppose how you want to adhere to accepted terminology or semantics. Sure, you have two wheels on the train side that pass through the center of the main plate, so you could say both the fourth and the second wheels are "center" wheels. You could also call them "intermediate" wheels since they are between the escape and barrel. The forth wheel is the pivot for the second hand and is directly connected to the train. You set it by stopping the train (hack), while the minute hand is connected to the cannon pinion which is friction fit to the second wheel. This has to move independently from the train when the keyless works is engaged so hands can be set. 

Edited January 26, 2024 by eccentric59

[RobBrandywine]

Thanks, so how is the hour hand connected to the cannon pinion?  It can't be attached to the same section as the minute hand because it rotates at a different speed.

[tomh207]

5 hours ago, RobBrandywine said:

Thanks, so how is the hour hand connected to the cannon pinion?  It can't be attached to the same section as the minute hand because it rotates at a different speed.

The hour hand goes onto the hour wheel which sits over the cannon pinion on the dial/motion works side. This is driven by an intermediate wheel and the minute wheel by the cannon pinion.

 

Tom

[Kalanag]

Source: „TimeZone Watch School, Illustrated Glossary of Watch Parts“ by Walt Odets

[nickelsilver]

To clarify, the barrel drives the center pinion, which extends through the mainplate and carries the cannon pinion, The center wheel drives the 3rd pinion, the third wheel drives the 4th pinion, and the 4th wheel drives the escape pinion.

 

The center pinion does indeed extend through the mainplate and carries the cannon pinion. The long pivot on the 4th pinion, which is part of the 4th wheel, extends all the way through the center pinion, to carry the seconds hand. And as Kalang's excellent drawing shows, the hour wheel rides on the cannon pinion, driven from the cannon pinion through the minute wheel to get the 12:1 reduction necessary.

[RobBrandywine]

So the hour hand fits onto that pipe on the hour wheel?  That must mean that it (the pipe) fits on the outside of the cannon pinion?  Is it just above the bottom gear on the cannon pinion and below the bulge?  And so the minute hand fits directly on the cannon pinion above the bulge?

Now that I know what to look for I can see plainly in The Watch Repair video I linked to above at 29:27 the hour wheel with its pipe being slid onto the cannon pinion with some space above the pipe for the minute hand to go on.

[nevenbekriev]

31 minutes ago, RobBrandywine said:

So the hour hand fits onto that pipe on the hour wheel?  That must mean that it (the pipe) fits on the outside of the cannon pinion?  Is it just above the bottom gear on the cannon pinion and below the bulge?  And so the minute hand fits directly on the cannon pinion above the bulge?

Now that I know what to look for I can see plainly in The Watch Repair video I linked to above at 29:27 the hour wheel with its pipe being slid onto the cannon pinion with some space above the pipe for the minute hand to go on.

Halleluyah!!!

If You had the watch dissassembled, You could answer by youself, with no others help, and this is much sweeter

[Jon]

1 hour ago, RobBrandywine said:

So the hour hand fits onto that pipe on the hour wheel?  That must mean that it (the pipe) fits on the outside of the cannon pinion?  Is it just above the bottom gear on the cannon pinion and below the bulge?  And so the minute hand fits directly on the cannon pinion above the bulge?

And the minute wheel is a 12:1 reduction gear so the cannon pinion which turns once per hour gives power to the minute wheel, which in turn powers the hour wheel so it turns once every 12 hours. Very simple

[RobBrandywine]

I've got the watch, a Seiko 5 with a 7s26C movement, partially disassembled -- baby steps. The problem is that the watch stops at night during the day change unless it has a good wind  At first I thought it was going to be bent or broken teeth on the plastic wheels involved in day/date change, but they all look good. So then I thought maybe I had a weak mainspring and have one on order. But in the meantime I saw a video saying this can happen if the tension of the cannon pinion against the 2nd wheel shaft is too loose or too tight -- I forget which. Probably too loose.

[eccentric59]

Just remember, while this is a good understanding of the connections between the train and the motion works, it is by no means universal or absolute. You will encounter many movements with variations on this, or completely different designs. 

3 minutes ago, RobBrandywine said:

The problem is that the watch stops at night during the day change unless it has a good wind

That wouldn't be a loose canon pinion. A loose canon pinion wouldn't stop the watch, it just wouldn't advance the date. A weak mainspring or binding in the calendar works would be my guess. Pictures would help.

[RobBrandywine]

Pictures of what?  Most of the watch is in little baggies.

[nevenbekriev]

48 minutes ago, RobBrandywine said:

I've got the watch, a Seiko 5 with a 7s26C movement, partially disassembled -- baby steps. The problem is that the watch stops at night during the day change unless it has a good wind  At first I thought it was going to be bent or broken teeth on the plastic wheels involved in day/date change, but they all look good. So then I thought maybe I had a weak mainspring and have one on order. But in the meantime I saw a video saying this can happen if the tension of the cannon pinion against the 2nd wheel shaft is too loose or too tight -- I forget which. Probably too loose.

See, understanding is needed, not blind following what they do in videos.

If the cannon pinion is loose, the watch will not stop, but the hands will. The seconds hannd will run, but the minute and hour hand will stop. Is it the case?

If the spring is weak, then the amplitude will be to lo and timekeeping bad. The spring is not likely to be that weak, but it is possible that it is not wound enough by the autowinding or the outer end slips and thus the spring unwinds. In such case, the power reserve will be to small. Is it the case?

The problem can be in calendare itself. To check the watch without calendare, take out the day wheel and if the watch will start to work correctly (without calendare function), this is the case...

[RobBrandywine]

All good tips.  When it is partly back together I'll do those things.  I do know that if I wound the watch by turning the crown wheel directly that it would run for the full 42 or so hours. I also believe the seconds hand was stopped each morning.

Edited January 26, 2024 by RobBrandywine