6431/6445 Question

[atkin68]

I have two of these right now (another on the way) - one is from Arnex via [mention]blueradish[/mention] , the second is from Rodania, and the third is another from Arnex. I'm just noticing some differences that I'm curious about.

1. #1 & #2 are marked on the ebauche under the balance with the UT 431/445, while the other Arnex (#3) is marked UT 6431/6445
2. #1 has a balance wheel with the little balance weights distributed around it like you see on most old pocket watch movements, while #2 from Rodania is smooth and has none of those little weights around the wheel. #3 has no balance wheel so I don't know which style it had.

Wondering if these differences are based on changes Unitas made over time, or if they were customized for Arnex/Rodania.

Thanks,
D

[atkin68]

The two balance wheels:





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[blueradish]

[mention]Yoda[/mention] [mention]unreformed66[/mention] [mention]djolemag[/mention]

[straps68]

The 6445 may be 20 years newer than the 445. I'm guessing they wanted to save costs by going with the obvioiusly cheaper wheel with no weights.

[atkin68]

The 6445 may be 20 years newer than the 445. I'm guessing they wanted to save costs by going with the obvioiusly cheaper wheel with no weights.

That’s fascinating - to look at the two side by side I would have guessed that the smooth wheeled movement was older. But then it is always possible it has been altered. Indeed I’m planning to put the Arnex balance and several other parts from it into the Rodania since I prefer the wheel train bridge on the latter.


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[Yoda]

The balance wheel without timing screws is the modern one.

[atkin68]

The balance wheel without timing screws is the modern one.

Thanks [mention]Yoda[/mention] , would you agree with [mention]straps68[/mention] that this was a downgrade in quality in order to cut costs?

[Yoda]

The balance wheel without timing screws is the modern one.

Thanks @Yoda , would you agree with @straps68 that this was a downgrade in quality in order to cut costs?

I agree with everyone regarding this, in the sense that ETA did this to cut costs. These "naked" balance wheels are as good as the older ones with timing screws and they are well made and balanced by drilling under the rim. My personal opinion is that it is a time consuming thing to make the one with timing screws and the new one was made to save time and money. Is it even possible to save time? My answer to that question would be NO, but efficiency and costs has something to do with this.
Personally I like the old style with timing screws, nothing beats the satisfaction when you have tweaked a balance wheel and adjusted for 3 to 8 adjustments and it spins forever.

[atkin68]

I need help from the masters on this movement. I've reassembled using a mix of the cleaner parts from each of the two movements, and everything seems in order but I can't get joy once it's wound up - won't run. I've dissassembled/reassembled a few times. Balance seems to swing fine. With the balance out, I can turn the escape manually and see it turning the 4th and 3rd wheels. Can't manually turn the center wheel or the barrel. Just can't figure out what's holding her back. Feels like things will turn but somewhere between the barrel and centerwheel it just isn't enough umph from the spring to get the train rolling.

[Yoda]

Have you tried with the center wheel fitted only?

Check if there is a slight play up/down in each wheel!

If that is spinning freely, try adding the barrel and try again.

If these two steps are ok, then add the train without the pallet arbor assembly.

Make sure it spins freely when you turn the crown a little, a bit of a backlash is even better.