DW Daytonas: How to tell a V72 case from a V7750 case?

[lhooq]

Perhaps a silly question to more capable watchsmiths than me, but...

 

I have a small pile of DW Daytona cases.  They should all accept a Valjoux 72 movement, but I've recently discovered that MANY of them do not!  Is there a quick and dirty way of determining which cases will take a V72, which will take a 7750, and which will take a Mystery Movement?

[freddy333]

No. Externally, except for the casebacks (which are taller for 7750 movements), the cases are the same. & with the lack of manufacturing consistency between them, I do not know of a reliable way to tell other than trying the movement out in a given case. I have had V72s fit in cases made for 7750s & I have had V72s that did NOT fit in cases made for V72s. I have less experience building 7750-powered Daytonas, but, so far, never had a problem fitting a 7750 into a case made for a 7750.

[chiman12]

Check to see if the movement clamp ridge on the case side is higher or lower down...

[lhooq]

Thanks, C, I'll check the internal ridges. Checking the caseback is a no-go, since all of my cases have the skinny type that fits both the V72 and the de-rotored 7750.

[lhooq]

Based on ChiMan's comment, I think I might have got it:  On the cases that will take a V72, the uppermost ridge will bisect the holes for the crown and pushers.  Cases that won't will have a top ridge that falls short of reaching the equator. 

 

Unfortunately, it turns out that my beloved FAP 6239 has one of the latter cases, a discovery made by The Zigmeister during a recent service.  I don't know how my old watchsmith managed to cram everything inside and get it running, but Zig refused to touch it in that precarious state.  The guts have been transplanted into a new DW case, which jmb will soon be working on. 

 

Ignorance was bliss!

[dieselpower]

Thank God for threads like this. They answer questions that have been mulling round my brain for ages. I suppose I'm not as stupid as I think. @ lhooq - yes, ignorance is truly bliss!

[TgfRulez]

Considering what Martin suggested, this should be what a V72 case appear..

 

 

[CptTripps]

I feel like an idiot asking this, but I can't find a link easily (yes...I've looked)

What's a "DW" case, and is there a link?

[cc33]

Dw is David Wong the only seller of a7750 daytonas, cases and dials with proper subdial spacing and functioning, they come as auto winds but can be converted to manual wind. He is notorious for sending the wrong parts or no parts at all so be very cautious actually don't bother, find one from the sales section or from a member. The v72 cases he offers are the cheapest and best bang for the buck

[dieselpower]

Just for clarity's sake, the sub dial spacing on a 7750 Daytona is not correct when compared to the gen/V72 version. The difference is small but noticeable the to the 'trained' eye.

[freddy333]

Ditto diesel's comments.