Change case seiko

[RELORT]

Is there a way to change the case from 4H to 3H movement?

[AndyGSi]

Welcome to the forum.

Not quite sure what you mean.

Can you post some photos.

 

[RELORT]

[AndyGSi]

So you're wanting to put the movement from the 4H watch into the 3H case? Why?

[tIB]

So because that Seiko is 3.8 rather than 4, if the movement fits the aftermarket case you would just need to refit the dial somehow - the day/date should line up with a 3o'clock crown. 

[RELORT]

@AndyGSijust want to look different and use a different strap.

[RichardHarris123]

24 minutes ago, tIB said:

So because that Seiko is 3.8 rather than 4, if the movement fits the aftermarket case you would just need to refit the dial somehow - the day/date should line up with a 3o'clock crown. 

I don't understand how the date would line up  

[AndyGSi]

My suggestion would be to sell it and buy another rather than ruin a perfectly good watch.

38 minutes ago, RichardHarris123 said:

I don't understand how the date would line up  

The spacing on the day/date discs means if you removed the dial the day and date would be inline with the crown.

Edit

The above depends on the movement.

Edited April 9 by AndyGSi

[RichardHarris123]

3 minutes ago, AndyGSi said:

The spacing on the day/date discs means if you removed the dial the day and date would be inline with the crown.

Of course, silly question when I think about it.  

[Neverenoughwatches]

2 hours ago, RichardHarris123 said:

Of course, silly question when I think about it.  

You forgot one of the forum's golden rules, " no question is silly " . A matter of repositioning dial feet.....I'd rather not. 

The day date disk stepping may not then line up with the date window of the new case. I wouldn't mess, like Richard said you might ruin a perfectly good watch. 

Lets look at an example of the alignments. The crown positions of the two cases are 3.8 ( old case ) and 3 ( new case ) , that's 15 degrees of case position difference.  In order for the date window to line back up at 3 the dial needs to be re-positioned on the movement 15° clockwise, thats the first obstacle.  Now looking at just the date disk alone, it's divided into 31 days , each date number and disk tooth is approximately 11.6 ° of rotation from it's neighbouring number. So each date position is also approx. 11.6° apart, since the new dial position is 15 ° from its original position and the date mech is set to that position..... the jumper can't be repositioned ! ... the date numbering will be approx 3.4° out of alignment with the date window.

Edited April 9 by Neverenoughwatches

[tIB]

5 hours ago, RichardHarris123 said:

I don't understand how the date would line up  

I think you've figured it and the above post explains far better than I will, but crown either side of 4 works (3.8/4.2), but bang on 4 needs a new day and date wheel.

Day wheel can be realigned on some, date is a different disc.

[AndyGSi]

5 hours ago, Neverenoughwatches said:

that's 15 degrees of case position difference

3.8 is 24 degrees so result would be 2 degrees out.

[Neverenoughwatches]

1 hour ago, AndyGSi said:

3.8 is 24 degrees so result would be 2 degrees out.

Well spotted Andy,  I missed out the 360° of a full dial divided the 4 minutes of an hour dial reposition.   Should have actually been . 360° ÷ ( 60÷4 )= 24° . I must do better maths .  Still won't line up,  11.6°  or multiples of would have.

 

1 hour ago, AndyGSi said:

3.8 is 24 degrees so result would be 2 degrees out.

 

[AndyGSi]

38 minutes ago, Neverenoughwatches said:

Well spotted Andy,  I missed out the 360° of a full dial divided the 4 minutes of an hour dial reposition.   Should have actually been . 360° ÷ ( 60÷4 )= 24° . I must do better maths .  Still won't line up,  11.6°  or multiples of would have.

It does line up which makes me believe it's not actually @3.8, even the Seiko literature states @4.

Edit

Just realised my maths was wrong too and it would be 0.8 Degree out 

Edited April 9 by AndyGSi

[Neverenoughwatches]

That's probably why they line up then. Each day on a date ring is spaced at 360° ÷ 31 days, which works out to 11.613 ° or as near as,  2 days is 23.226° . Thats probably where the crown is postioned  from 3 onwards on the original case.

Positioned at 4 would be 360° ÷ (60 ÷5) = 30°

Who has a seiko 5 and a protractor handy ? 

It looks like the crown is at 19 minutes, which I assume is where the 3.8 comes from .

[AndyGSi]

38 minutes ago, Neverenoughwatches said:

It looks like the crown is at 19 minutes, which I assume is where the 3.8 comes from .

Yes and very difficult to tell even close up if the 19 minute / 3.8 is accurate.

If you worked on a 30mm diameter dial you're looking at around 94mm circumference so 0.8 degree works out about 0.2mm

[Neverenoughwatches]

4 minutes ago, AndyGSi said:

Yes and very difficult to tell even close up if the 19 minute / 3.8 is accurate.

If you worked on a 30mm diameter dial you're looking at around 94mm circumference so 0.8 degree works out about 0.2mm

That's pretty damn close, the original case crown position could easily be just 2 date clicks away from 3 o'clock.  The OP still needs to decide if he wants to move the dial feet. Do seikos have dial feet ?.... I have no idea .........whats a Seiko anyway .   The 4 crown position doesn't leave a crown imprint  in your wrist when doing push-ups......stick with the original case OP.

[tomh207]

They are usually 28.5mm diameter for these dials. 
 

Tom

[AndyGSi]

21 minutes ago, tomh207 said:

They are usually 28.5mm diameter for these dials. 
 

Tom

Was just using 30mm as an example to show how small 0.8 degree would be on the circumference.

[tomh207]

Just now, AndyGSi said:

Was just using 30mm as an example to show how small 0.8 degree would be on the circumference.

No worries Andy, I was just trying to be helpful as you and Rich were nearly getting to minutes and seconds, maybe radians weren’t granular enough

 

Tom