Servicing a 6497

[thealphabeta]

I've just stripped, cleaned and rebuilt an old 6497 that wasn't running properly. After rebuilding it winds fine and I cans ET the hours etc. it won't run though. The balance wheel and pallet fork doesn't move. Have I over tightened something or maybe put something in wrong? Any ideas? Sent from my iPad using Tapatalk HD

Edited January 19, 2013 by DaveR

[chris5264]

you mean the balance wheel will not move at all...even with a puff of air?

[Rolexman]

Something is wrong with either your gear train or pallet fork / balance. Check by removing the balance and pallet fork. If your escape wheel won't turn if you wind, you know it's the gear train. If it does the problem lies with your pallet fork or balance wheel.

Let us know.

[w0lf]

if it's an asian movement make sure you didn't flip the pallet bridge, they're not keyed and can go on both ways, this will freeze your pallet. your hint will be the lack of reaming around the bridge screws

[thealphabeta]

Great thanks guys. It will move but not will full range of motion. I think it might be upside down. The pallet fork has a long and short pin on ever side. Who've one case down, long or short? I'll have another go Sent from my iPad using Tapatalk HD

[thealphabeta]

So, the escape wheel works just fine and rotates, so not the gear.  Clearly I've buggered the pallet installation

[thealphabeta]

So i've put it all back together, again.  But, it seems like the escape wheel isn't catching the pallet fork.  I'm not sure if I have it the right way up.  If I have the shorter protrusion on the bottom it sits too low, or at least it looks that way??  It's the only part of the ETA manual that doesn't have clear orientation

[thealphabeta]

Arghhhh, after about 5 attempts I've realised what the problem is.  I think.

 

The pallet bridge has lost its jewel, it's just a straight hole.  So, that must have come out at some point, so the pallet fork isn't sitting right and therefore not doing anything.

So, without a jewel????  I've clearly knocked it out somehow and I can't see it anywhere.  Can I get another?

[thealphabeta]

Managed to order a new pallet bridge from cousins in the UK.  I made the assumption that t jewel would be pre inserted

[Rolexman]

Great monologue.... Glad to see you figured it out

The jewel probably came out because you mounted the pallet fork bridge the wrong way like wOlf indicated. This caused the pallet fork pinion to push out the jewel. Be sure to get it on the right way next time by looking at the screw head slots (was also mentioned by wOlf)

[thealphabeta]

So, I've nabbed a pallet bridge out of another 6497 that I had in parts. It's working and ticking along but very slowly?  Any thoughts?  The hairspring isn't whizzing round as viciously as I'm used too.

 

Suggesting friction maybe somewhere? 

[chris5264]

can you stick on a min hand and time it?

[thealphabeta]

This is why you guys know what you're doing

 

Minute hand is on.  Will keep track of time.

[Rolexman]

Check the end shake of the balance. That is the vertical play between the balance jewels. You can only do it if the balance is at rest. If there is too little end shake it causes too much friction. Ergo slow en short balance swings. IMO this topic should be over at 'movement Q&A'...

[thealphabeta]

I looked over there but there didn't seem to be much going on so thought I'd get more feedback here.

 

I'll check that.  So far it has kept time.  Maybe I'm just comparing with a high beat 6497 which is why it looks slower?

[chris5264]

using the min hand over an hour is a pretty crude method...but I've found that if its keeping close time,,,,usually you can do an adjustment.....anything wrong with the hairspring usually can't keep time even over an hour....

[thealphabeta]

I think you're right. I have a steinhart and a custom build that I did recently and both are much faster beat than this. Here is the video. It's running fine time wise. Been going for nearly 3 hours and still accurate.

http://videobam.com/PiqXQ

[thealphabeta]

Ps my Kello app picks it up at 18k bph

[thealphabeta]

Amplitude??

[Rolexman]

Yup... amp way too low. This won't keep accurate time on the wrist.

[thealphabeta]

What causes low amplitude? The mainspring? Worn out/damaged? That's why I serviced it. It's an old watch (my first ever rep) and I wasn't too worried about the outcome. Should I buy a new mainspring?

[Rolexman]

What causes low amplitude? The mainspring? Worn out/damaged?

That's why I serviced it. It's an old watch (my first ever rep) and I wasn't too worried about the outcome.

Should I buy a new mainspring?

Could be all the things you mentioned and a 100 extra.....

Regulator studs touching the hair spring, coils out of sinc, broken balance staff, broken jewels, damaged barrel wall etc etc. Unfortunately....

Just bring it to a local repair guy. Otherwise you will spend all your money on parts you may even not need.

[thealphabeta]

How do you even access the mainspring in the barrel? Thanks rolexman but I don't feel like I've learnt if I do that. I rather spend £50 and find out I can't fix it and have learnt something than just hand it over and be none the wiser. If I can't repair it then ill probably not both doing anything more. The mainspring is £12 in the UK but I assume that's not the full barrel assembly.

[Rolexman]

How do you even access the mainspring in the barrel?

Thanks rolexman but I don't feel like I've learnt if I do that. I rather spend £50 and find out I can't fix it and have learnt something than just hand it over and be none the wiser. If I can't repair it then ill probably not both doing anything more.

The mainspring is £12 in the UK but I assume that's not the full barrel assembly.

Noted. The steps I would do. You need a good 10x loup though.

1. Check the end shake (ok?)

2. Check if the hair spring touch-and-releases the rate regulating stud (ok?)

3. Check if balance staff pivots are (ok?)

4. Turn balance and determine if all coils are spaced equally (ok?)

5. Check the jewels of the gear train for cracks (ok?)

6. Diassamble the barrel and look at the barrel wall and clean oil main spring.

This last step can even be dangerous if you never done this before as the main spring is packed in the barrel with a lot of force.....

Edit:

In between step 2 and 3 I would recheck the pallet fork if it moves freely. Wind the watch and gently tap the fork. It should move on it's own 1 teeth of the escape wheel and than lock.

Good luck!

[thealphabeta]

Ok. You've totally exposed my ignorance to this project. I wouldn't have a clue how to do any of that. Maybe I should just admit defeat