Sweep second problem.

[rogart63]

Have an old movement with sweep second attachment. An extra third  wheel and an pinion. The problem is that the pinion is wrong. Either it's to many teeth or wrong cut of the teeth. When i put the extra third wheel on the movement it stops. Going to see if i can fix it anyway. But my question is if a wheel or a pinion has more or less teeth in this construction. Would the watch run okay anyway, Only the second hand would go faster. As the extra third wheel on top of the movement turns the second hand pinion. 

Edited November 27, 2018 by rogart63

[WatchMaker]

If it's an extra wheel providing the drive for the seconds then this is known as 'indirect centre seconds' - example diagram below.

If you have the wrong pinion i.e. the green shaded pinion one in the diagram then, yes, this should only effect the seconds hand in some way.

Have you found a picture of your movement type on the web to compare the pinion?

[yankeedog]

movement type ? If the movement runs without the center second, the problem lies there. If the teeth are correctly sized the gear would be over or under sized depending on the number of teeth. if the gear is of proper diameter and tooth count correct  i think improper shape could cause a jam. inspect the teeth closely under magnification.If you can somehow get a picture of the movement online , do a tooth count.tooth much tension on retainer spring could also cause a problem

Edited November 28, 2018 by yankeedog
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[yankeedog]

the principle at play here is gear reduction. if the second hand turns once per minute  and the hour hand turns once per hour you have a 60:1 ratio. if the minute hand turns once per hour and the hour hand once in twelve , that is a 1:12 ratio. the only way to know for sure is to count the teeth and do the math.rule one problem out the move on to the next variable.

[rogart63]

24 minutes ago, yankeedog said:

the principle at play here is gear reduction. if the second hand turns once per minute  and the hour hand turns once per hour you have a 60:1 ratio. if the minute hand turns once per hour and the hour hand once in twelve , that is a 1:12 ratio. the only way to know for sure is to count the teeth and do the math.rule one problem out the move on to the next variable.

Was just me wonder how it worked. But got the answer i wanted from Watchmaker. The movement is a Doxa 14 with sweep second. I misplaced the sweep second in the wash. Found a pinion on a Eterna 600 that fitted. But think it had more teeth or had a different cut on the teeth. But think i have found the right pinion now.