Winding watch moves rotor

[Tim]

Has anyone else seen something like this? I have two gens and one rep that do this now all with ETA 28XX movements. When you manually wind the watch, sometimes the rotor engages and it becomes momentarily difficult to wind. While winding, the rotor will actually start to turn and you can make it do actual revolutions just by winding the stem. What causes this and is it tearing the guts out of my gear train when it happens?

In a similar vein of movements being difficult, I also have one rep with an ETA 28XX movement that will not start running after being wound from a dead stop. If I very lightly tap the edge of the case on the table, it will then start and run fine. What up with that one?

/Tim

[stang]

I also have one rep with an ETA 28XX movement that will not start running after being wound from a dead stop. If I very lightly tap the edge of the case on the table, it will then start and run fine. What up with that one?

Tim,

I had this experience with my SMP 300M Chrono w/ the Asia 7750 movement. After winding it via the crown when it had stopped completely, the seconds hand wouldn't move, even after dozens of turns of the crown (tried turning the crown in both directions since I didn't know which way was correct. Apparently, clockwise is the correct direction to wind). After approx 40 turns of the crown (both directions) I tried winding the watch using the rotor by "swirling" the watch (short circles in the air to get the rotor turning via inertia). This caused the seconds hand to start running immediately.

Later on, I was able to get the watch running from a dead stop using just the crown ... but sometimes I have to "jiggle" it a bit to get it going. Not sure why(?).

Jeff

[NRG]

It's probably due to lack of lubrication of the click wheels or a pair of tight wheels in the auto wind bridge. As the Auto wind mechanism does not detach during hand winding the rotor can move as you note. You should always handwind these movements slowly...and probably only occasionally to get the watch started.

[chris5264]

I had a similar problem with one of my gens.

http://www.rwg.cc/members/index.php?showto...626&hl=2824

I ended up removing the winding bridge, doing an ultrasonic clean and oiling it with D5. I put it back and it didn't help things. I have only recently picked up on this advice about handwinding,,,,although I don't think I ever did much handwinding I think I may have done it too fast. The 28** should come with instructions that tell people to hand wind very slowly and only when necessary.

[RWG Technical]

If the rotor turns while handwinding, it's due to sticky/damaged click wheels. The click wheels (2X) are one way sprag clutches, and when the rotor is winding the watch, one wheel locks while the other freewheels depending on the direction of the rotor. These wheels and the gear train from the rotor to the mainspring, is a gear reduction unit, ie many rotor turns, for one mainspring turn.

When you handwind, your turning the mainspring directly, and this motion is amplified and sent up to the click wheels. If you do this fast, or a lot, or if the clicks are somewhat sticky, instead of freewheeling, one of them catches, and spins the rotor. It's supposed to freewheel and not spin the rotor.

Also due to the fact this is a gear reduction unit designed to run one way (from the rotor down to the mainspring) when you handwind, you now have gear multiplication (from the mainspring up to the rotor), which causes the clicks to spin like mad, for a slight crown movement.

Fix is to try and clean them in an ultrasonic bath, or replace them, and keep handwinding to a minimum, and only when needed.

Question 2, the beat is out on the movement, the alignment between the balance, pallet, and escape wheel is off, which causes the escape wheel to lock on a pallet stone instead of self starting. All the winding in the world will not unlock the pallet stone, but moving the stone will unlock it and get it going, your moving the stone by moving the pallet, which rocks when you set the balance wheel in motion by tapping the case.

You need a watch analyser to read and adjust the beat.

RG