ETA Unitas 6498-1 - Timegrapher Results

So after winding my new watch and allowing it to run for 24 hours to "settle in", or "distribute the lubricants", 😉
or just let it get a feel for it's new life, I gave it a full wind and ran a series of scans, the results are shown below.

I let it run for another 24 and did another series.

To me the results look pretty good, but I'd like some opinions from those much more in touch with interpretation of results than myself.

So any observations / comments are welcomed from @Archer, @ChrisN, @Canuck, @Stewart H, @Mad Dog and any others who'd like to jump in.



PS: The Test Period was the default 4 Seconds. Is there any reason to use a longer test period (e.g.: 60secs), if so why?

Cheers

Jim

Thanks a lot Chris, a lot to absorb and some reading to do.
I'll check things out and run another series and see how it goes.
If results are similar I guess it will mean a service.
I have the service docs so just have to see if my epilame is still in date (or even still in the bottle).

Could servicing it improve on those results? Change, maybe, but really improve?

Hmmmm. Food for thought. I'll do some more testing using Chris' guidelines and see what the result is

Hi Jim,

First question I have is, what grade is this movement? Standard or Elabore, or something else? That will make a difference on the tolerances that ETA states.

ETA calls for stabilization time (time between measurements after you move the mic stand) at 20 seconds, and measuring time (what they call integration time) is specified as 40 seconds as the minimum. I don't recall what kind of machine you have, but if you are using the typical graph, the way I was taught to take the measurement was to find a label on the machine, preferably near the right hand side - this is the point where you will look at the number and write it down. Picking a specific spot avoids the temptation to cheat if the number is bouncing around. So watch that spot on the screen, and as the line is coming across, when it hits that spot look at the numeric display and write the number down.

I think the test period is referring to the averaging time - not sure but the machines typically use a running average that is updated every 4 seconds as the default, but that isn't the time over which you take the actual measurement of the rate.

For a Standard grade 6498-1, the Delta is allowed to be 40 seconds, measured over just 2 positions, and for the Elabore grade it's 30 seconds over 3 positions. ETA's disclaimer is that 95% of all watches produced will fall into this tolerance, so the tolerance is pretty wide actually. Your result is clearly well within those tolerances. But these are just a starting point in my view, and I do use Elabore grade movements and get them to single digits over 6 positions certainly before I ship the watches. So to answer Canuck's question yes they most certainly can be improved with servicing and a little adjusting. If you have the time and ability to do some dynamic poising, you can get results that are actually very good:



I admit I don't get them all to this level, but it shows what can be done with these movements if you have the skills. Right after servicing this one had a Delta of 11 seconds, and it took 2 shots at the dynamic poising to get this result. I could have made this better actually by opening up the regulating pins just a hair, but 2 seconds over 6 positions is "good enough." 😉 Just for comparison, Omega allows 12 seconds over 5 positions at full wind for their COSC watches.

I'm inclined to agree with Chris that the excessive amplitude dial up is because it was just wound - I would expect to see a larger dial up/down difference at full wind +24 hours if it was something other than that. ETA recommends 1-3 hours after winding for the first checks. Maximum allowed amplitude is pretty high on these compared to some watches, but ETA recommends no higher than 320 to avoid rebanking.

BTW I buy new movements and they always get serviced before I use them. I often find that the factory doesn't do a great job adjusting certainly, but also find dry jewels on occasion, and even have found cracked/chipped jewels.

Cheers, Al

Thanks for all the guidance folks. I've been experimenting and have figured out a plan.

I have a simple "Weishi" type machine that gives Rate/Amp/Beat and adjustable Lift Angle/Timing period, so tomorrow I'll do a more structured run based on:

Full wind, wait 1 hour, Set LA 44º, Test time 60 seconds, give at least two minutes to stabilise, take reading when trace hits the edge.
Set to next position, wait for a full trace (about 30sec) to stabilise and then two minutes to read, repeat.

I think I may have got some readings wrong in the first pick, but doing ad-hoc checks still gives a Delta of about 13 to 16 seconds.

PS: Al, it's an Elabore grade, but as the supplier said it was factory lubricated I haven't pulled it apart but I may do so when I get back from our holiday in July.