Certina 25-661 and 25-66 differences

[Bopmd]

Hello! 

I am working on a certina 25-661, but the forth wheel is broken. I can not find parts for the 25-661, but I found the forth wheel for a 25-66 for a reasonable price. I asked the seller and he wasn't completely sure if they would fit. Does anyone know? 

[HSL]

Most of the parts in the drivetrain is interchangeable between these two, I just put a new center wheel to a 661 and it worked just fine.
It is just the date part which is obviously lacking on the 66.
I can try the fourth wheel later if you still wounder.

[Bopmd]

2 minutes ago, HSL said:

Most of the parts in the drivetrain is interchangeable between these two, I just put a new center wheel to a 661 and it worked just fine.
It is just the date part which is obviously lacking on the 66.
I can try the fourth wheel later if you still wounder.

Yes, please. That would be very kind of you! The seller said it might be top short for a seconds hand by the way

[watchweasol]

Hi   I have attached the tech sgeets for the certina 25-66 and 25-661 and also 25-65 range so you may make a comparison.Cheers

1808_Certina 25-66.pdf 1809_Certina 25-661.pdf 1806_Certina 25-65, 25-651, 25-652 (1).pdf

[HSL]

To jogg my memory I took a look at the two side by side, one can express it short like this, everything concerning the date function is different beween these two. The parts for the 25-661 is a tad bit longer and that goes for everything involved with the time keeping (Part No. 205, 227, 245, 250 ,260,  the seconds hand is mostly no problem since the seconds hand tube is so long (goes on 227). 
Makes sense since the date wheel builds a small bit.
So to be on the safe side you should just go with the correct parts in this case.
Some pics during the check.

[Bopmd]

7 minutes ago, HSL said:

To jogg my memory I took a look at the two side by side, one can express it short like this, everything concerning the date function is different beween these two. The parts for the 25-661 is a tad bit longer and that goes for everything involved with the time keeping (Part No. 205, 227, 245, 250 ,260,  the seconds hand is mostly no problem since the seconds hand tube is so long (goes on 227). 
Makes sense since the date wheel builds a small bit.
So to be on the safe side you should just go with the correct parts in this case.
Some pics during the check.

Oh, ok. Thanks for the reply! Would it be too much to ask if you could measure the length between both?

[HSL]

I took some quick measurements.

205  (Center wheel), 25-66 = 3.09mm (slightly longer than 25-661) and 25-661 = 3.07mm
227  (Sweep second wheel), 25-66 = 5.06mm and 25-661 = 5.52mm
245  (Cannon pinion), 25-66 = 1.8mm and 25-661 = 2.33mm
250  (Hour wheel), 25-66 = 1.13 and 25-661 = 1.63mm

Measured a couple of the Center wheels and it seems the 661 has a slightly lower version.

[Bopmd]

1 hour ago, HSL said:

I took some quick measurements.

205  (Center wheel), 25-66 = 3.09mm (slightly longer than 25-661) and 25-661 = 3.07mm
227  (Sweep second wheel), 25-66 = 5.06mm and 25-661 = 5.52mm
245  (Cannon pinion), 25-66 = 1.8mm and 25-661 = 2.33mm
250  (Hour wheel), 25-66 = 1.13 and 25-661 = 1.63mm

Measured a couple of the Center wheels and it seems the 661 has a slightly lower version.

Did you mean 5.60mm? If so it shouldn't be that big of and issue? I think I'll take my chances. Unless you want to sell me one?

[HSL]

If you mean the sweep second on a 25-66 beeing 5.60mm instead of 5.06mm? No unfortunately not.

[Bopmd]

1 hour ago, HSL said:

If you mean the sweep second on a 25-66 beeing 5.60mm instead of 5.06mm? No unfortunately not.

Oh, ok. Thank you for the help I guess I'll have to find the right part then... Or learn to use my lathe