Seiko 6309a Pallet Fork Problems

[Dave84]

Hi guys,

I have been working on my first full strip down and service of an old 6309a I picked up. 

When reinstalling the pallet fork, I am noticing that when I put a turn of power to the mainspring to test the fork in its position that its not locking the escape wheel and instead pivoting back and forth uncontrollably at high speed for a second until it runs out. I have also tried to reinstall it a few times but keep getting the same results. I am assuming that have damaged something ... 

Any advice appreciated 

Thanks 

Dave 

[jguitron]

The pics looks alright as far as I can tell. Tough with just one pic but I’d say it shouldn’t be doing that. 
 

given my own mishaps, I have to ask without meaning any offends... is it possible you placed the fork upside down and so the stones are not at the same level as the escape wheel and hence free spinning? Or is the escape wheel placed incorrectly? All teeth ok?

 

keep us posted!

 

Julian 

 

[Nucejoe]

Looks like you have no shellac left on pallet jewels. What cleaning solution you used.

Pallets having moved deeper inside the fork slot causes fluttering. 

I check side shake on the fork arbour and escape wheel as well.

[Dave84]

Hi Julian- no worries, it is something id likely do, but no i checked its in correctly. the escape is sat within the pivots and moving freely. 

Nucejoe - I didn't actually clean the pallet fork, but I did notice that the jewels were sat pretty deep in the fork and they might not be connecting properly with the escape wheels. 

[watchweasol]

Hi  on this one I would side with nucejoe  It looks and sounds like the the pallet jewels are set wrong and mislocking on the escape wheel. Watch closely the action of the pallet, apply a small amount of power and watch how the jewels lock, control the release of the power with some peg wood.  Do not run the watch at speed as it may break or chip the jewels.  one answer is to obtain another pallet and try the same tests as re setting the jewels whilst not impossible will be time consuming and may not achieve the desired results.

[Nucejoe]

I take it you manually clean pallets. So I make a habit of dropping the fork in bath of avgas and gently brush (soft brush) pallets alot. 

I think more friction and drag come to the play during escape teeth run on the face of pallets , than all other low tension components combined. Good clean and proper lube on a good pallet face is your ticket to good amplitude.

Escape teeth scratch pallets face especially if dry, so I make a habit of routinely  checking pallet face under high magnification. 

But in this case, I am affraid replacing complete fork with a good one is your best option. Watchweasol once called pallet adjust a minefield, everyone agreed.

 

[Dave84]

Thanks guys

Luckily i have a donor movement here and will swap out the pallet fork today to see if it makes a difference, i suspect it will. 

Cheers 

Dave 

[Dave84]

The donor pallet fork worked ! thank you guys .