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Navichief

ORF Seamaster 300M movement pictorial; unidirectional autowinding and other differences from VSF

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Navichief

Hello,
I had an ORF Seamaster 300M on the bench recently. It was the first one I've serviced in comparison to many VSF's. Here are some thoughts and observations on the movement aspect of it. I recently purged a lot of photos, so I'm a bit lacking in VSF movement shots at the moment.

Both movements are decorated A2824's. My general impression is that VSF uses higher quality clone A2824s. For instance, VSF uses balances with Lyre style Incabloc shock protection found on higher end grades of 2824, vs ORF's Novodiac shock spring. General fit, finish, and cleanliness is also better on the VSF movements.

The automatic rotor is attached differently from VSF. I actually prefer ORF in this regard, as it has no glued on decoration to fall off.

ORF:

IMG-20220113-150843987-2.jpg

VSF:

IMG-20201130-113013972.jpg

The decorations are also handled differently. VSF is one large piece that fits over the 2824 and attached with 3 screws under the dial. ORF has smaller plates that attach directly to the 2824. The nod goes to ORF here as the movement is much easier to access for repair or regulation than on VSF.

ORF:

IMG-20220113-153822878.jpg

IMG-20220120-122837889.jpg

VSF:

IMG-20201130-113448590.jpg


Now, what I consider the biggest difference, is how the automatic bridge has been altered in the ORF. I believe this was to improve the look of the decorated movement. One of the reversing wheels was removed, the bridge has been cut and altered, and a click spring installed. This makes the automatic winding system on ORF's unidirectional only.


IMG-20220114-094230889.jpg
IMG-20220114-094057327.jpg
IMG-20220113-162107792.jpg
IMG-20220113-162046714.jpg

There are also custom parts there that won't be available to replace.
Functionally you won't notice a difference in winding or power reserve, but unidirectional movements like the 7750 and Miyota 9015 often get labeled as "loud and helicoptory" as the rotor has less resistance in one direction.

I'm not sure how to end this, other than I hope you find that interesting.

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jcagara08

Great write up mate, would an ETA 2824 be a straight drop in replacement once the A2824 craps out on both ORF and VSF SMPs?

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Navichief
10 minutes ago, jcagara08 said:

Great write up mate, would an ETA 2824 be a straight drop in replacement once the A2824 craps out on both ORF and VSF SMPs?

VSF yes you could switch to ETA, but you would lose the black balance wheel unless you reuse that part. 

ORF I would say no, unless you drill and countersink new screw holes to allow the decorations to attach to the ETA plates. I'd have to have another ORF in front of me to look at it side by side with a plain ETA to be sure. You could keep the plates from the A2824 and use ETA parts for the rest. Plus that automatic module would have to swapped over.  

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judas9r

That is really very interesting. Thanks for sharing. 

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Wolf359

Your informative post is much appreciated :clap: Need a new blue faced summer stunner, never really bonded with the Superocean.   The ability to  more easily use an ETA 2824 is a difference maker. 

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tribefan

Thanks for this post, I'm pinning it.

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Chainen

Thanks, as a newbie I really enjoy reading these types of posts.  I learn so much from the experts here.  Thanks Nav!

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processengr

Hi, Thank you for this pictorial!

I want to regulate my ORF Seamaster- can I leave the movement in the watch, and just remove the rotor to get at and remove the decorative plate (both?)

then bump the timing fork a bit, put rotor back on and test?

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Navichief
Hi, Thank you for this pictorial!
I want to regulate my ORF Seamaster- can I leave the movement in the watch, and just remove the rotor to get at and remove the decorative plate (both?)
then bump the timing fork a bit, put rotor back on and test?
Yes, in fact you don't have to remove the rotor. Just push it out of the way.

The piece over the balance is separate and the only thing you have to remove. Look at the pic of the ORF parts in the tray. You can see the separate decoration that covered the balance.

Sent from my SM-F926U1 using Tapatalk

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processengr
34 minutes ago, Navichief said:

Yes, in fact you don't have to remove the rotor. Just push it out of the way.

The piece over the balance is separate and the only thing you have to remove. Look at the pic of the ORF parts in the tray. You can see the separate decoration that covered the balance.

Sent from my SM-F926U1 using Tapatalk
 

Thank you! 

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