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Inside the Best Replica Rolex Daytona |
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Articles -
Watchmasters Corner
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Written by Ziggy Zumba
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Page 2 of 4
12 position on the 7750
So lets
work our way around the dial starting at the 12 position in a CCW direction. The 12 position
is where the output from the 30-minute counter comes through from the back of the movement.
The output is a small shaft on which the sub dial hand would normally be fixed.
On
this modified movement, a new gear is pressed onto the shaft, where the sub-dial hand would
normally be placed. The piece of the shaft left sticking up is cut off flush with the gear.
To get the motion from the 12 position to the 3 position requires 2 more gears as you see
here.
9 position
The 9 position
has the running seconds. This is a shaft extension from the 2nd wheel on the other side of the
movement, to which a sub-dial hand would normally be attached. The modified model needs to
have running seconds at the 6-position. This is done with some clever thinking, and some
special gears.
First off, a new gear is pressed onto the
shaft as was done to the 30-minute counter, and the remaining shaft is cut off. Two more new
gears are added to take the motion first towards the right and upper part of the movement, then
a gear with a large hollow center part is placed over the hour hand shaft, taking the motion
down, and 2 more gears are added to finally get the motion on the 6 O’clock position.
So
how well does this work? Not bad - but not great either. There is a fair amount of slack in
the gear teeth, and the result is that the seconds’ hand “jerks” as it moves around the dial.
The other possible long term problem is the friction of the big hollow gear on the hour hand
shaft, any bit of old oil or dirt in this critical area will bring the movement to a halt.
Look at any movement, there are jewels and tiny pivots at all rotating points throughout the
gear train to reduce friction to a minimum. The friction from the new gear here
Must be very high (certainly if we compare it to a
pivot set into a jewel) so I wonder how that will affect the accuracy and life of the
movement.
The one area that will cause problems is beyond belief (at least to me
it is).
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Last Updated ( Tuesday, 14 August 2007 )
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