God - there HAS to be a better way to replace the geartrain bridge.....

[deadmeat 0]

Speaking mostly to cheap-ass 7750 and similar movements with cheesy stamped thin-metal gears. Once everything is placed and aligned to the top plate (3rd, 4th, center and escapement wheels - not to mention any additional gearing for complications) and you have to replace the bridge. Jesus, I'm going to pull out what little hair I have left getting all the bits lined up properly to the jewels and sandwiching them back together. I know - everyone has the same issue, I'm just hoping that maybe someone has the "most awesome, perfect magic bullet alignment technique, jig, God idea, whatever". Any help or advise appriciated.

[10:10 Watch Repair 1]

Which bridge?

[deadmeat 0]

The wheel bridge - covers the main gear train wheels (and mainspring barrel on some movements). On the 7750 I'm currently working on (and most I have in the past) it's such a total bitch to re-align and get right. Just wondering if there is a better way than what I have been doing (after getting the gearing placed into the top plate, sort-of finagling all the bits into their perspective top jewel receivers on the bridge time after time until I finally get it "right" and can screw-down the bridge).

 

This is never easy, but the particular movement I'm working on presently has a couple of extra complications that place 2 additional gears in the train making the bridge realignment almost impossible. Some are hidden and very difficult to see if resting properly in the jewel bearings. I get 3 or 4 in and invariably I missed one or one popped out. Very much a patience testing exercise that I'm failing at the moment.

[UmpaHimself 222]

This thread is waaaaaaay over my head.

[deadmeat 0]

Well, at the moment it's over mine as well.........this particular movement may be getting the hammer treatment...........

[moredhel 0]

Send it back to the china assembly line. She'll get it re-assembled in 10 mins flat. ^^

[10:10 Watch Repair 1]

OK, first, mainplate, not topplate I am assuming.

 

Here's the pro way:

 

Make sure all of your pinions are seated in their bottom jewels, and, as much as possible, sitting upright.

 

Place the bridge carefully holding it with brass or CF tweezers firmly (sometimes flat tipped tweezers help.)

 

You need to determine from experience how to best view the bridge when reinstalling. On a 7750 I choose to view with a 5x loupe from slightly above the bridge. (On the auto winding bridge, for comparison, I view it from the side or even a little underneath to line up the staked in post with the auto winding gear.)

 

Getting it close while placing it is half the battle.

 

The next battle is getting the upper pinions in their respective jewels. Two things are key:

 

1. use sharpened pegwood, or a plexi stick to apply light pressure on the top of the bridge.

2. don't be afraid to lift the movement (in it's holder) to view it from different angles.

 

Remember, through a loupe you have no depth perception, so aligning a top pivot means you have to view it from different angles to get it right.

Lastly, learn what a pivot looks like in a jewel. That may sound simple, but through a 5x it's hard to see, and IMO you need the 5X for depth of field.

 

Work from the mainspring out, with the escape wheel being the last to "pop in." It's also the easiest pivot to break, so be careful with the amount of pressure you exert on the top of the bridge with your pegwood, plexi, or pick.

 

Some of these things, as well as a steady hand, come with experience, but once you know the technique you can begin gaining the experience. Perfect practice is the only thing that makes perfect...

 

Also, watch some youtube videos on assembly.

[James. 4]

I concur

[deadmeat 0]

OK, first, mainplate, not topplate I am assuming.

 

Here's the pro way:

 

Make sure all of your pinions are seated in their bottom jewels, and, as much as possible, sitting upright.

 

Place the bridge carefully holding it with brass or CF tweezers firmly (sometimes flat tipped tweezers help.)

 

You need to determine from experience how to best view the bridge when reinstalling. On a 7750 I choose to view with a 5x loupe from slightly above the bridge. (On the auto winding bridge, for comparison, I view it from the side or even a little underneath to line up the staked in post with the auto winding gear.)

 

Getting it close while placing it is half the battle.

 

The next battle is getting the upper pinions in their respective jewels. Two things are key:

 

1. use sharpened pegwood, or a plexi stick to apply light pressure on the top of the bridge.

2. don't be afraid to lift the movement (in it's holder) to view it from different angles.

 

Remember, through a loupe you have no depth perception, so aligning a top pivot means you have to view it from different angles to get it right.

Lastly, learn what a pivot looks like in a jewel. That may sound simple, but through a 5x it's hard to see, and IMO you need the 5X for depth of field.

 

Work from the mainspring out, with the escape wheel being the last to "pop in." It's also the easiest pivot to break, so be careful with the amount of pressure you exert on the top of the bridge with your pegwood, plexi, or pick.

 

Some of these things, as well as a steady hand, come with experience, but once you know the technique you can begin gaining the experience. Perfect practice is the only thing that makes perfect...

 

Also, watch some youtube videos on assembly.

 

 

Kind of what I have been doing, but will continue - Thanks for the info. Got to get my timing down a few minutes, guess with continued practice.....