Crown positions, an issue

[helidoc]

I would be grateful for a technical perspective from the TZ collective on the crown action of my Bell&Ross BR02

It’s a fairly recent acquisition, 13 years old, service history unknown. It keeps great time.

The crown is screwdown, so when released it should be pull to position 1 to wind, date in position 2, hack and hand set in position 3

The issue is that the stops between them are sometimes positive, but usually muddy and indistinguishable. In position 3 the crown often slips so the seconds restart, but it is in no mans land between position 2 and 3 as the date is not in the setting position, but the movement isn’t hacked and the hands can’t be set. I think the watch can be wound before position 1, and sometimes the jump is between 1 and 3.

I have been in touch with Lee who is B&R service agent, and maybe I should just have it serviced.

I’ve attached a couple of timegrapher pics, the amplitude seems good, the watch keeps great time on the wrist and the power reserve was 41.3h for an SW200-1, which seems good.

I’ll probably end up servicing it, but as the movement is running well I wondered if there was a crown only option. It would help if so understood what might be happening

Cheers

Dave



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[ben4watches]

sounds as though something is askew with the keyless works, could be loose or maybe a bent stem stopping it locating correctly.

A service would indeed have this rectified.

[JGJG]

Sorry to hear that D. In fact, I’m surprised many more watches don’t have crown operation issues - *every* time I see a crown operated online, it brings me out in a flush of mechanical sympathy for the poor machine! Perhaps the prior owner was just a little indelicate.

[helidoc]

It’s cool J, I always have a watch service fund available, it’s a keeper and it’s a cost of this weird enthusiasm. It’s not that I can’t set the time, date or hack the movement, it’s just a bit indistinct between jumps

D


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[th6252]

The muddy feeling between positions could be due to wear or lack of lubrication in the crown mechanism or the movement itself. It’s also not uncommon for older watches, especially those with unknown service histories, to develop such issues.

[Dynam0humm]

When you pull the crown out what you can feel is the setting lever acting on the setting lever spring. This is a typical setting lever spring with the notches that you can feel arrowed -



If it was simply a lack of lubrication then the click between the positions would be more pronounced, so it's more likely that the notches on the spring are worn and it needs replaced.

However, another issue that could cause the same vagueness is a lack of lubrication on the crown gasket. If there's a lot of friction between the crown and crown tube it can make it harder to feel the clicks because the gasket is putting up resistance, so it might just need a dab of silicon grease on the gasket to get it feeling 100% again. On watches with the gasket enclosed within the crown all you need to do is pull the crown out to the hand setting position, put a dab of grease on the crown tube, then press it back in and rotate the crown a few times to spread the grease. If the gasket is on the stem of the crown and enclosed in the tube then the crown will need to removed before you can get to the gasket. I'm not sure which set up a B&R has, but I'd be checking the gasket lubrication first before sending it off for a full service.

[helidoc]

When you pull the crown out what you can feel is the setting lever acting on the setting lever spring.

Thank you so much for such a detailed and technical answer

Dave


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