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Servicing a 6497 movement & Building a watch - Part1

Odyseus

Renowned Member
1/11/11
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0
OK, Time to give something back to the members :)

Over the last year or so, I've been stripping down and rebuilding many watch movements! Now I'm going to start the write up's!! (I should start up a blog if I get the time and figure out how to do it??)

Anyway, I hope it's of use?? More parts to come in the coming days :)

Servicing a 6497 movement & Building a watch
In these tutorial I will show you how to:-
(1) Strip down a naked A6497 hand wind movement.
(2) Reassemble the movement, indicating where to oil.
(3) Fitting a dial and watch hands.
(4) Fitting movement into a case, adjusting stem length and adding strap.
(5) Regulating movement

Part 1 - Taking the movement apart!

Now this movement is real breeze to work on and so if you want to learn how to service a movement, then this is the one to start with! ?. So here we go.. starting with the movement, our trusty Asian 6497 hand wind movement, shown here in Figure 1.

NOTE that there is a spring washer that fits over the pinion! Don’t forget this before fitting the dial!!!

Figure1_zps5f773377.jpg

Figure 1 An Asian 6497, very close to the genuine Unitas 6497 movement and very reliable.

Mount the movement onto a movement holder (I use a Bergeon 4513 universal movement holder).
First thing is to remove the hour pinion (Hour Wheel Part #250). This is the pinion that the hour hand is pressed onto. It should just lift off without any effort.

Figure2_zpsd3cc8ae9.jpg

Figure 2 Removing the hour wheel.

With the hour wheel removed, the Cannon Driver Pinion (Part # 240, minute wheel) will be exposed. This is the pinion that the minute hand is pressed onto.
It is removed by using a Presto type hand puller as shown in Figure 3.

Figure3_zps0cc3c495.jpg

Figure 3 Removing the Driver Cannon Pinion (Part No 240) using some watch hand pullers.

We can now disassemble the keyless works. On the 6497 there are only two positions, winding (ie Crown/stem the normal pushed fully in) and the hand setting position (Crown/stem pulled fully out).
Figure 4 shows the keyless works in the winding position. The winding pinion is turned by the stem and rotates the crown wheel on the other side of the movement. The sliding pinion is disengaged with the setting wheel.

Figure4_zpse72b5d67.jpg

Figure 4 Crown/stem pushed into the winding position.

Figure5_zps084304b6.jpg

Figure 5 Crown/Stem pulled out to the hand setting position

As you can see from Figure 5, the Sliding Pinion (Part #407) is engaged with the Setting wheel (Part #450) so that you can set the hands.
Remove the single screw and be VERY careful when removing the keyless Cover (Setting lever jumper part #445) as the spring underneath (Yoke spring Part #440) may spring out!!

Here (shown in Figure 6) is the keyless exposed (In the winding position).
The lower section of the minute wheel drives the Canon Pinion and the top section drives the hour wheel.
What you may notice, is that when the keyless is put into the winding setting position, the Minute wheel, Intermediate wheel and setting wheels are continuously turning as the watch runs. This is because they are all connected to the minute wheel, which is driven by the Canon Pinion and turning of the Minute wheel turns the hour wheel.
When the keyless is set to time setting position, there is not enough torque from the Canon Pinion, to drive all the setting wheels, Pinions and stem and in a sense hacks the movement by stalling it!
Anyway back to the disassembly of the movement! All the keyless components can be removed (start with the yoke spring and don't let it fly away!).

Figure6_zpsa90dd83c.jpg

Figure 6 Close-up of the keyless works components.

We now turn over the movement and remove the crown wheel (Part #420)..

Figure7_zps6ee53d5b.jpg

Figure 7 Movement turned over and fitted in jig. Crown wheel has been removed

Next we can remove the Ratchet Wheel (Part #415).

Figure8_zps6f325588.jpg

Figure 8 Ratchet wheel removed.

And now the Click Wheel (Part #425) and Click Spring (Part #430).
Note that one end of the click spring sits in a small hole and the other raised end of the spring normally sticks up in the small recess on the click wheel (as shown)

Figure9_zps11777e8d.jpg

Figure 9 Click wheel removed, showing position of click spring.

We can now proceed to remove the barrel bridge (Part #105). By removing the three Screws for Barrel bridge (Part #5105).
Carefully lift off the barrel bridge.

Figure10_zpsb200843e.jpg

Figure 10 Remove the three screws for Barrel Bridge.

With the barrel bridge removed, you can remove the barrel assembly on it’s own – useful if you just want to replace the main spring or suspect that the main spring requires oiling, without having to disturb the rest of the drive train.
Assuming we want to remove the drive train then we remove the two Train wheel screws (Part #5110).

Figure11_zpsbd197150.jpg

Figure 11 Barrel bridge removed, exposing the Barrel assembly and centre wheel.

We can carefully remove the Drive Train bridge (Part #105) to reveal the drive train. The centre wheel drives the minute wheel and results in turning of the hour hand. The third wheel is under a lot of torque from the main spring and along with the second wheel, dilutes the energy from the main spring to the escape wheel and balance wheel, which performs the timing function of the watch.

Figure12_zpsb1381924.jpg

Figure 12 Drive train exposed.

This section describes removing of the drive train..
Start by removing the Centre Wheel (Part #201) – If it doesn’t come out then you forgotten to remove the Cannon Driver Pinion (Part # 240) !!

Figure13a_zps7b44106f.jpg

Figure 13a Removing the Drive Train & Barrel.

Figure13b_zps1661fa03.jpg

Figure 13b Removing the Drive Train & Barrel.

Figure13c_zps84cfae1c.jpg

Figure 13c Removing the Drive Train & Barrel.

Figure13d_zps756ed857.jpg

Figure 13d Removing the Drive Train & Barrel.

Figure14a_zpsf5a7a36e.jpg

Figure 14a Removing the Drive Train & Barrel cont.

Figure14b_zps71a69137.jpg

Figure 14b Removing the Drive Train & Barrel cont.

The only thing left now, will be the Balance Wheel Assembly. You only really need to remove this, if you feel that the balance wheel is dirty or needs to be replaced. In which case, remove the Screw For Balance Bridge (Par t #5121) and remove the balance wheel assembly and dip in Bergeon ‘One-Dip’ Part # 2552.

Examine the pallet fork (Part #710) and pallet fork stones for dirt or damage.
If OK, then we can proceed to oil and re-build the movement.

When oiling, generally only apply so as to smear the contact area with oil. If too much oil has been applied, remove the access with some Rodico.

Part2 Looks at oiling and re-building the movement :)
 
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bobandshawn

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29/10/13
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Fantastic friend! I just tried to work on my first 6497 and lost the Yoke Spring and Setting Lever in a mishap. I found the replacement parts at Offrei and hopefully they will fit. This tutorial will help me put the movement back together!!!

Thank You,
Bob
 

paulvillo

Renowned Member
6/6/13
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Awesome, thanks!
Just brought my 390 back to life (misaligned wheels).
 

shelby1501

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18/10/11
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Is it possible to access to the second wheel (part 220) without removing a dial?
 

Major Tom

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Great job, and much appreciated.

Where would you look if a handwinding movement won't wind?

When I pull the crown I can only adjust the time, there is no function between screwed in and setting the time. Hours and minutes only. Radiomir 232

Thank you,