Does anyone know if a watch back from a 3570.50 will fit on a 3572.50? I like the back of the 570 more than the 572. Thanks.

 

It will fit and anytime you want to swap let me know.

 

Although the case back with the display glass will technically fit, changing from one to the other is not as simple as just swapping the case back. As Ash noted, the non-display back model has the inner antimagnetic cover in it, so the movement spacer (called the enlargement ring) is quite short. The cover snaps on the enlargement ring, and the cover presses on the inside of the case back, and this holds the movement securely in the case.

If you just swap backs, and remove the inner cover, the movement will not be held in place by anything. The screws that hold the movement to the enlargement ring, do not hold the enlargement ring to the case, so the movement can flop around unless you happen to have a very tight fitting enlargement ring in the case.

To do this job properly, the enlargement ring has to be exchanged as well as the case back. The new enlargement ring is much taller, and an O-ring goes on top of it to provide a soft and compressible surface for the inside of the case back to tighten on, which holds the whole movement secure in the case.

Cheers, Al

 

Thanks Al
I realise that you can't just swap the casebacks, as you explained, you need to swap the rings as well as the cover that goes with the solid back.

 

On an 861/1861, it's just the stem. The 321 enlargement ring has drilled holes where the pushers go through it, where the 861/1861 models have slots.

So on an 861/1861 version, you can change the ring without taking the movement out of the case, or taking the stem out of the movement. You just unscrew both case screws, lift out the ring, drop the new one in, and put the screws back.

Note that these comments are for the Speedy Pro watches - others like the Mk. II have a slightly different system, with no inner cover and they use case clamps under the case screws. In these the clamps actually do secure the movement in place in the case.

Cheers, Al

 

While we are on the subject, I would urge anyone attempting to remove the dust cover for whatever reason, to take extreme care not to allow the movement to tilt even slightly in the case. Its easy to cause a lot of damage if the cover is tight and doesn't want to come off.
My own efforts first time ended in an expensive repair.

 

what happened?

 

By removing the inner anti-magnetic oover, will the watch more prone to magnetized?

 

Yes.