AP diver low beat mod issues

[Vester71]

Watch: 

I'm on my second AP diver with a low beat conversion. First was a stainless from Vac from 3 years ago and I sold it almost immediately as the watch was too big (or so I thought). Turns out it was running about 10 min fast a day after Vac regulated. The buyer had it serviced and I figured to was a fluke and never asked about it again.

 

I have a new carbon diver with a custom forged carbon case and the low beat mod - brand new and was just serviced and regulated by the gentleman that built it. 

 

Movement:

A2824 that received a conversion to 21,600 bph with a genuine ETA balance wheel, escapement wheel and fork. To improve reliability and power reserve a genuine ETA barrel and mainspring were added. Movement was cleaned, oiled and regulated during assembly.

 

Issue:

Running 30+ minutes fast a day already. I've done a little reading and think there might be something with these conversions that make them tough to regulate or run fast due to the parts used.

 

Anyone have any experience here?

 

Thanks!

[Tim]

Adjusting bph with a new balance wheel. Hummmm. I haven't been keeping up with mods that much but has this mod been checked out? You generally have to vibrate a hairspring to the correct bph matched to the balance wheel. Without vibrating the hairspring +/- "something wild" is about as good as you are going to get. It sounds like a hack job mod that I can't quite figure out why you'd want to do it???

You can attempt to approximate vibrating a hairspring with a timing machine, but results from a timing machine are averaged and not nearly sensitive enough to give an accurate solution. The only proper way to do it is with a Luthy tool and it is considered an archaic art that is rarely done today.

[ceejay]

The ETA 2824 is/was available from 18,000-36,000 there are 4 different models, standard, eleborated, top & chronometer.

The latter 2 have different escapements, shock protection and barrel springs.

 

This in itself would throw up all sorts of mix & match issues.

 

I don't think most people understand the complexities & tolerances that are present within watch movements and this is where bodging hacks like this are always going to throw up issues of reliability of accuracy.

[Tim]

The ETA 2824 is/was available from 18,000-36,000 there are 4 different models, standard, eleborated, top & chronometer.

The latter 2 have different escapements, shock protection and barrel springs.

 

This in itself would throw up all sorts of mix & match issues.

 

I don't think most people understand the complexities & tolerances that are present within watch movements and this is where bodging hacks like this are always going to throw up issues of reliability of accuracy.

Well the Eterna original movement pattern has been replicated with all sorts of variation. But I took the OP at his word and assumed a 2824 with 28.8K bph. The major functional variations always had (that I know of at least) different movement numbers.

Just seems like a goofy goal in one's quest! Everyone usually turns their noses up at the Chinese 21's in favor of something with 28 in the magic numbers. Here is a mod that will give you what everyone pans! If bph is an important aspect for someone seeking an accurate rep, why didn't they start with a Chinese 21? With a little extra work they can be just as durable as a 2824 and much more accurate than this mod.

[Vester71]

Ended up going with a Tissot Powermatic 80 movement. The quest for a "perfect" and overly accurate rep continues!