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fireftr45

Mainspring winder for Seiko 7S26

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Hi All,  I have exhausted google and various pdf's on the Bergeon mainspring winder sets, and I have wasted enough money on ebay buying worn out vintage "universal" winders.

Does anyone know which Bergeon winder drum/arbor you need for the seiko 7s26 mainspring?  Any help here would be greatly appreciated!  Thank you, ,,,,,,Erik

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I’ve found that for some Seiko mainspring it’s best to use a combination of one handle and another drum. The appropriate size drum has too wide of a post.

Anyway, my 2 cents.

May just have to do it by hand...


Sent from my iPhone using Tapatalk

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I know Seiko parts are not so easy to buy these days. Seiko back in the 70’s and 80’s advised, you should replace the barrel complete after (I think 5 or 7 years) you’re not supposed to take them apart. Its possible you will not find a winder that will fit.

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4 hours ago, fireftr45 said:

Hi All,  I have exhausted google and various pdf's on the Bergeon mainspring winder sets, and I have wasted enough money on ebay buying worn out vintage "universal" winders.

Does anyone know which Bergeon winder drum/arbor you need for the seiko 7s26 mainspring?  Any help here would be greatly appreciated!  Thank you, ,,,,,,Erik

There is no barrel supplied by Bergeon that fits the Seiko 7s26. If I remember correctly with the Bergeon set they are either too small or to large. I used a K&D winder that I usually use for the larger pocket watch barrels. Oldhippy is correct Seiko recommend a new barrel & mainspring. I have noticed Cousins have the mainspring as obsolete.

However I have done a little research & the consensus is the mainspring size required is:  0.95 x 0.12 x 400 x 10.5.

Which is ref: GR2378X

Cousins have this in stock.

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I haven't measured one but it seems widely reported that the ID of the 7S26 barrel is either 10mm or 10.5mm.

If you check Cousins web site it lists the bergeon winders by size.

https://www.cousinsuk.com/product/watch-bergeon-winders-by-size

No.6 has a diameter of 9.8mm so woud be the right size.

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Thank you all!!!  I am finding out that Seiko has discontinued making a lot of these mainsprings for 7S, 4R, 6R.  I guess they just want you to buy a new movement.  So a generic spring will most likely have to be sourced.  They don't even sell the barrel complete anymore. (or I just haven't found a viable source yet)

I have gotten a little frustrated lately, as I started purchasing spring winders from ebay.  The first turned out to be a pocket watch spring winder that is too deep and the spring winds up in a ball.  The second set I bought was an adjustable K&D 123, A & B, that fits the barrel but the right winding knob has the nib that grabs the spring hole worn off, so it won't wind.

I am still very new to this.  This is the first spring I am trying to wind up and it has been a source of stress so far.  The spring has gotten kinked several times so I just decided to keep practicing on it till the tail broke off last night.  I will say I almost had it once, but when trying to get the spring to let go of the knob, as I removed the winder knob the spring popped out.

I suppose I could just keep trying to find a newer knob for the 123A, but I am gravitating towards spending more for the Bergeon and be done with it.  My thinking is I could always add new drums one at a time as needed over time (as I don't have $1K+ to drop on a whole set).

Well again Thank You all for your help.  I will keep trying.

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