Measuring watch accuracy

[KarlS]

Looking for some help from an expert. I understand that the watch is tested at 6 different positions. In order to assess the accuracy do you merely add the sum together and get an average or group into the 4 crown measurements and the 2 dial (as the amplitude is different. Also where do you get a list of manufacturers lift angles as mine looked pretty low for a new watch. Anyway this is what I measured over 3 minute intervals.

-3.0 s/d. 262 degrees. 0.1 ms
-1.6 s/d. 260 degrees. 0.0 ms
-1.2 s/d. 261 degrees. 0.1 ms
-2.4 s/d. 253 degrees. 0.1 ms
3.7. s/d. 289 degrees. 0.3 ms
3.8. S/d. 288 degrees. 0.2 ms

It's obvious the ones dial down and up. So it loses time on the wrist and gains lying down or up. Do we work the average?

[Friar]

I'm not an expert, but I've found that a simple average of the readings comes quite close to my experience on the wrist. Here is one source of lift angles--http://hiro.alliancehorlogere.com/en/Under_the_Loupe/Calibres_by_Make

[SearChart]

You can probably find the correct lift angle if you Google it.
What I learned to do is fill in the stats in a schema of both fully wound and half wound. Then fill in a formula and a good watch should then always get a score below 5. I don't have this stuff at hand right now but I could make a picture of it next week and try to explain it properly.

But this is how we check ETA, valjoux, Omega movements, etc. I'll probably have to do it completely different once I started my RSC internship.

[KarlS]

Thanks that's very useful. I think I guessed it was an average but then I was looking at my one watch and it was very consistent at say 2.2 s/d - hardly deviated over and hour and thus I would think that would be the rate for the day. Then there was another that had a -6 in one position and +4 in another which would give the same avaerage of 2 s/d and yet my gut would have said the first watch was better as it didnt fluctuate too much. Guess thats the danger of getting a Lepsi Watch scope you start over analysing everything!!

[SearChart]

Do you just check your movement's accuracy or do you have it out of the case with the automatic complication removed? If not it's kinna hard to wind the watch exactly untill it's half wound.
I always look at how many 360 degree turns the ratchet wheel makes, say this would be 9 then I wind he watch until the ratchet wheel made 4.5 turns. It's recommended to use a little blob of rodico as a reference point on the wheel.

I could do the quality control check just for fun if you like, your watch is obviously running very precisely so it isn't necessary.
If you can give me the stats of the 6 positions both fully wound and half wound I will fill in the schema and show it to you. Dial up and down is obvious, but I need to know what positions the other stats are from.

[KarlS]

Originally Posted by SearChart

Do you just check your movement's accuracy or do you have it out of the case with the automatic complication removed? If not it's kinna hard to wind the watch exactly untill it's half wound.
I always look at how many 360 degree turns the ratchet wheel makes, say this would be 9 then I wind he watch until the ratchet wheel made 4.5 turns. It's recommended to use a little blob of rodico as a reference point on the wheel.

I could do the quality control check just for fun if you like, your watch is obviously running very precisely so it isn't necessary.
If you can give me the stats of the 6 positions both fully wound and half wound I will fill in the schema and show it to you. Dial up and down is obvious, but I need to know what positions the other stats are from.

Thanks that would be great. I will do the stats on teh half wind position. Guess just look at the Power Reserve and see when half way or fully wind the other watch and let it run down half the power reserve. The stats above I think were fully wound and is:

dial up, dial down, crown right, crown down, crown left, crown up,

[SearChart]

Originally Posted by KarlS

Thanks that would be great. I will do the stats on teh half wind position. Guess just look at the Power Reserve and see when half way or fully wind the other watch and let it run down half the power reserve. The stats above I think were fully wound and is:

dial up, dial down, crown right, crown down, crown left, crown up,

Yes that would be pretty accurate to determine a half wound mainspring.
I'll have access to those papers on Tuesday, will get back to you then.

[Friar]

Originally Posted by KarlS

Thanks that would be great. I will do the stats on teh half wind position. Guess just look at the Power Reserve and see when half way or fully wind the other watch and let it run down half the power reserve. The stats above I think were fully wound and is:

dial up, dial down, crown right, crown down, crown left, crown up,

I was thinking that the last two readings are from the dial being up (CH) and down (FH) as their amplitude is the highest. I don't suppose it has to be that way but it is on all my watches.

[KarlS]

Apologies you are correct. I was reading upwards on the thread when typing

[KarlS]

What do these readings mean:

Full Wind Half Wind

2.6 s/d 257 degrees (0.1) m/s 4.2 225 degrees (0.1) m/s
1.8 s/d 260 degrees (0.2) m/s 6.0 231 degrees (0.4) m/s
(2.1) s/d 232 degrees (0.4) m/s 0.6 190 (0.1)
(2.1) 252 (0.2) (1.2) 205 (0.1)
(2.0) 247 (0.2) (7.2) 192 (0.2)
(3.4) 242 (0.2) (6.4) 188 (0.2)

Average:
(0.86) 248 (0.2) (0.66) 205 (0.18)

I guess i was surprised hpow low the amplitude is. The watch is only 8 months old so guess doesnt need a service. Maybe I have the lift angle wrong. I just used 52 degrees and not sure if it makes a huge difference.

[KarlS]

Doesnt allow to tabulate so looks bit complicated

[padi56]

Originally Posted by KarlS

Looking for some help from an expert. I understand that the watch is tested at 6 different positions. In order to assess the accuracy do you merely add the sum together and get an average or group into the 4 crown measurements and the 2 dial (as the amplitude is different. Also where do you get a list of manufacturers lift angles as mine looked pretty low for a new watch. Anyway this is what I measured over 3 minute intervals.

-3.0 s/d. 262 degrees. 0.1 ms
-1.6 s/d. 260 degrees. 0.0 ms
-1.2 s/d. 261 degrees. 0.1 ms
-2.4 s/d. 253 degrees. 0.1 ms
3.7. s/d. 289 degrees. 0.3 ms
3.8. S/d. 288 degrees. 0.2 ms

It's obvious the ones dial down and up. So it loses time on the wrist and gains lying down or up. Do we work the average?

Originally Posted by KarlS

What do these readings mean:

Full Wind Half Wind

2.6 s/d 257 degrees (0.1) m/s 4.2 225 degrees (0.1) m/s
1.8 s/d 260 degrees (0.2) m/s 6.0 231 degrees (0.4) m/s
(2.1) s/d 232 degrees (0.4) m/s 0.6 190 (0.1)
(2.1) 252 (0.2) (1.2) 205 (0.1)
(2.0) 247 (0.2) (7.2) 192 (0.2)
(3.4) 242 (0.2) (6.4) 188 (0.2)

Average:
(0.86) 248 (0.2) (0.66) 205 (0.18)

I guess i was surprised hpow low the amplitude is. The watch is only 8 months old so guess doesnt need a service. Maybe I have the lift angle wrong. I just used 52 degrees and not sure if it makes a huge difference.

Originally Posted by KarlS

Doesnt allow to tabulate so looks bit complicated

IMHO Karl you are over-thinking accuracy as long as your watch performs to a AVERAGEof between -4 to+6 seconds over any 24 hour period give or take a second or so either way.Then you cannot expect more from any purely mechanical watch,remember there are 86400 seconds in a day.And out of the box most all Rolex are 99.994% accurate or slightly better. Lifes to short to fixate on a second or so either way truth be told no purely mechanical watch will keep 100% perfect time close yes but perfect no.

[SearChart]

What movement is it? The Rolex 3135 should be a lift angle of 52.
Also could you give me the stats like you did the first time. Just two rows of 6 positions.

[KarlS]

Originally Posted by SearChart

What movement is it? The Rolex 3135 should be a lift angle of 52.
Also could you give me the stats like you did the first time. Just two rows of 6 positions.

I will PM you so not as to be over analytical to other members. Cheers

[SearChart]

Originally Posted by KarlS

I will PM you so not as to be over analytical to other members. Cheers

Fine

One thing is for sure though, like Peter said your watch is pretty darn accurate. As you can see from the first stats.