What does this mean? - Timeograph readouts explained

[pabler]

Very interesting info!

 

[GreenHornet]

Oke, let's address these one by one.


We have 'BEAT: AUTO 28800' - what is the 28800 referring to? Is it how many beats per hour? Yes, it is beats per hour. In this case (28,800) it equates to 8 ticks per second. Common beat rates are:

5 beats per second....= 18,000 bph = 2.5 hz
5.5 beats per second = 19,800 bph = 2.75 hz
6 beats per second....= 21,600 bph = 3 hz
7 beats per second....= 25,200 bph = 3.5 hz
8 beats per second....= 28,800 bph = 4 hz
10 beats per second..= 36,000 bph = 5 hz

Then we have 'Lift Angle: 52.3 degrees' what is that all about? Lift angle is the angle of rotation of the balance in which the roller pin is in contact with the pallet forks.Lift Angle is used to along with the rate to calculate Amplitude. It is not measured by the machine, it is set before testing to the correct value for the watch. This is usually between 50 and 52 deg for common MVT types but much higher for a co-axial escarpment like in a gen Omega. A Unitas 6497 however is only 44deg. If this is not set correctly all measurements will be off. I am not sure of the correct beat angle for an a7750 MVT but no doubt a little research on the gen fora would find it. If not, an email to Shanghai Watch (in SIMPLE english) requesting the correct lift angle, and amplitude for the 3L chronograph would get an answer.

'Rate: + 0.00s/d' is this seconds per day lost or gained? Roughly speaking, yes. It is not a real world measurement tho as it varies depending on the position of the watch which is why COSC MVTs are tested in 5 or more positions.

'AMPLITUDE: 305 degrees' does this refer to sound of the movement? No. Amplitude is the number of degrees thru which the balance wheel rotates, usually around 260 to 315deg. anything above 315 is getting a bit on the high side and may cause issues. 305 is fine, 280 to 300 is more or less perfect.

'BEAT ERROR: 0.7ms' ? The difference (in milliseconds) in the length of beats. The lower the better, anything below 1.2ms is fine in these MVTs, below .9 is desirable, 0 is perfect with the COSC testing requiring below .5 in all positions.

Hope that clears that one up.




Col.

Just got the QC pics for my PAM00288K and based on TrailBoss' explanations, it seems that my watch is a bit off. What say ye who are well versed in such matters. Is this something that should be addressed with Angus prior to accepting shipment?

Rate: +009
Amplitude: 247 deg

 

[andries]

Come on. You just quoted post that explains what readings mean and in what range amplitude should be. And then you ask question about same matter. Do you really expect to hear something very different?

9sec/day - is it good enough for you or not? While watch movement is breaking in, this will slightly change. There is no need to address it right now.

247deg - average amplitude.


Are we going same path as QC pics when everyone was reposting their QC pics asking others for approval? Information in this thread was given so people could make educated decisions on their own.

 

[trailboss99]

Looks good to me.

 

[GreenHornet]

Come on. You just quoted post that explains what readings mean and in what range amplitude should be. And then you ask question about same matter. Do you really expect to hear something very different?

9sec/day - is it good enough for you or not? While watch movement is breaking in, this will slightly change. There is no need to address it right now.

247deg - average amplitude.


Are we going same path as QC pics when everyone was reposting their QC pics asking others for approval? Information in this thread was given so people could make educated decisions on their own.

My friend, first off, thank you kindly for the clarifications provided. The only way to learn is to ask questions so that one truly understands.

The reason I inquired was because of Trailboss' explanation. I took them litterally.

He stated the amplitude was generally 260 - 315 deg range. 247deg is BELOW that, so I wanted to know if it indicated an issue. He addressed the high end, but didn't comment on the low end.

He does not specify a number for rate: s/d, but I read in another thread that +5/-5 was acceptable tolerance, otherwise regulation was needed.

We all start the learning curve somewhere, so I guess I'll continue to ask NOOB questions. They seemed pretty legitimate to me.

 

[RobbDizzle]

+/- 5 is about ideal (COSC certifed is +/-5)...I'd say anything under 15 out of the box is just fine.

Bottom line, as stated before in the thread (and I think Boss himself said it, IIRC) that if it runs well and keeps good time, all is well. It's a beautiful watch, wear it in good health!

 

[Fortey]

This has been a great read, glad to learn this stuff. Now I'm pretty psyched about my UPO, looks like it should be pretty accurate as long as a long chain of mailmen are careful with it...what could go wrong?

 

[Watch-Out]

Has anyone found out correct settings for a7750?

 

[robmack]

Back to my earlier question, assuming one has the correct equipment to test the movement and that the correct beat rate n lift angle are used, how is the amplitude adjusted?

The amplitude of the balance is determined mostly by the friction encountered through the drive train. Having the watch professionally serviced will be the greatest contributor to returning the amplitude to factory specification. On a timegrapher, the line traced by the machine showing the average change in rate over time is usually a good indicator of problems with the drive train -- i.e. wandering line, sudden broken discontinuity in the line, non-linear line, etc. will point towards problems like worn pivots, insufficient endshake or sideshake, misaligned pivots, etc.

If i recall correctly, Regulation of most movts are usually done by the arms near the balance spring..and minimal loss/gain is achieved thru trial and error..

That is correct. There is usually an adjustment on the balance bridge to lengthen or shorten the balance spring which decreases or increased (respectively) the oscillation rate of the balance with will directly affect the rate of the movement. There is also another adjustment at the balance spring anchor point that can vary the beat error and bring that value closer to the 0.0mS desired setting. Both of these settings are trial and error.