Accuracy

[ratty]

Hello

How accurate are manual Speedmasters? What's the general consensus?

[phopwood]

When I got mine out was about 10 sec a day fast. After a year out was 14 sec fast. I put this change down to it bedding in etc. so I regulated it back to 4 sec a day fast. This is an average.

I am more than happy with 4 sec. I don't on the other hand like watches that are slow.

Peter

[ratty]

Mine appears to be running about +10 secs per day. I'm wondering what Omega sees as being acceptable with a view to asking them to adjust it.

[Watch Professor]

When I first bought mine (new from an AD) it was running +9 sec./day. I demagnetized it (I have an inexpensive watch demagnetizer at home) and now it's running at +2.5 sec./day. It's interesting to note, that the way you lay it down at night effects the accuracy- crown down slows it down, dial up speeds it up. So, you can regulate it yourself by the way you store it to get it pretty much to +_ 0.

[ratty]

Thanks for the info. Regulating the watch by leaving it in a certain position is fine if you take it off, but not so good if you don't.

[jmsrolls]

Mine run +/- 2 secs/day.

Fr. John†

[rockmastermike]

knowing these are not chronometers, I think it reasonable to be under 10 either way but no more than that. preferably 7/8/9 but again, not expecting COSC.

Fr John, did you have yours adjusted or just happen to find a one with those tolerences?

[jmsrolls]

Originally Posted by rockmastermike

knowing these are not chronometers, I think it reasonable to be under 10 either way but no more than that. preferably 7/8/9 but again, not expecting COSC.

Fr John, did you have yours adjusted or just happen to find a one with those tolerences?

My brown dialed Speedy Pro has been running +/-1 sec/day since I opened the box last Christmas day.

My custom cal. 861 runs +/- 2 secs/day since the movement was restored in 2004.

I regulated my 46-year old cal. 321 to +/- 2 secs/day.

In the watch box, they sleep dial up.

Fr. John†

[ratty]

Wish mine was as accurate as some of yours!

[TattooedGQ]

Mines around +4 to + 6 depending on how long I keep it wound for, and how often i wind it.

[ratty]

For the past few days i have wound the watch in the morning, lunch time and in the evening and it appears to be noticeably more accurate! I don't understand this at all. Surely the accuracy should maintain without the watch having to be wound every 4 hours or so?

[dieseldragon]

If you are obsessed with accuracy then get a quartz! A mechanical watch movement can be very accurate, but there are many factors that will affect that accuracy, conditions its worn in, temperature, movement etc.. My watches are accurate that I only have to adjust them every month or so.. My PO is my daily wearer and needs little adjustment, I sometimes check it when I have to change the date at the end of the month, my sub only gets worn every few weeks or so for a night out so accuracy is not an issue.

But as this subject has come up again, I have set both the Sub and the PO to the clock on my computer and in 24 hours I will see what the result is. This is the first time in all my years of owning watches that I have ever felt the need to do this!

I am going to keep both watches on my wrists over night and during work tomorrow I will keep both on me and rotate them as I take my watch off for the dirty jobs, this should give them even wrist time.

Sub is a 1994 14060, that has been independently serviced 3 times. The PO is from 2007 and was serviced before I got it at around xmas.

[ratty]

Originally Posted by dieseldragon

If you are obsessed with accuracy then get a quartz!

I'm not obsessed with accuracy but I do like machines to work as designed / intended.

I used to work for Rolls Royce Aero working on jet engine components. Working to near enough for most of the time was not an option for obvious reasons. I fully accept that mechanical watches are usually not as accurate as quartz watches but I do like things to be as accurate as can reasonably be expected. I know that a gain of 5 to 10 secs per day is not the end of the world but if this can be reduced I do not see a problem trying to reduce it, after all, I'm sure that the watch was not purposely designed to be this inaccurate?

[dieseldragon]

Originally Posted by ratty

For the past few days i have wound the watch in the morning, lunch time and in the evening and it appears to be noticeably more accurate! I don't understand this at all. Surely the accuracy should maintain without the watch having to be wound every 4 hours or so?

manual wind watches will behave this way the spring winds down after time, theres only so much the power reserve can cope with. Imagine a clock work car, it will go slower and slower until it finally stops. Automatics keep the watch wound more consistently.

[Andad]

Originally Posted by dieseldragon

manual wind watches will behave this way the spring winds down after time, theres only so much the power reserve can cope with. Imagine a clock work car, it will go slower and slower until it finally stops. Automatics keep the watch wound more consistently.

IMO a manual or automatic movement when fully wound would run slower than when both movements are at say 1/4-1/2 power. At 1/4-1/2 power the torque is lower, the amplitude of the escapement is smaller and the movement will run faster.

[dieseldragon]

Originally Posted by directioneng

IMO a manual or automatic movement when fully wound would run slower than when both movements are at say 1/4-1/2 power. At 1/4-1/2 power the torque is lower, the amplitude of the escapement is smaller and the movement will run faster.

If you say so, I can't argue with that!

My PO has lost 6-7 secs in approx 48 hours

[Bdel]

Omega PO +1.5 secs/day

[ratty]

For the last week or so I have worn the watch and kept it fully wound up, topping it up every 3 or 4 hours or so.

I don't understand why but it has kept almost perfect time!

[Tools]

Originally Posted by ratty

For the last week or so I have worn the watch and kept it fully wound up, topping it up every 3 or 4 hours or so.

I don't understand why but it has kept almost perfect time!

Mechanical watches are engineered to have as little variance as possible in the upper part of their power torque (or through a known power curve).. Isochronism is the term for a uniform rate of performance over a known power reserve..

This is why watches have 50 hour power reserves.. It isn't so you can let your watch run down for 50 hours, it's so that you wind it (or self wind it for automatics) before it loses too much power reserve; taking you out of the optimum power curve and accuracy suffers..

It's possible that if you wind it every 4 hours, you are keeping it in the "sweet spot" for Isochronism.... but it seems to be a bit of a nuisance for a second or two, and likely not universal among watches...........

It's a lot easier to regulate it with positional placement at night. Like Fr. John, my Speedy with 1861 movement is around +2 a day, but I can better that by placing it crown up at night.. I wind it every morning before putting it on..

[Genevapics]

My SpeedyPro runs about +2 secs/day.

[Ken Cox]

If a watch consistently gains or loses the same amount of time per day, I consider that an accurate watch that simply needs regulation.

[ratty]

That's a good point.

Perhaps I should have thought more before describing it as inaccurate.

[Widows Son]

I've never checked any of my watches for accuracy!!!! If they're so close that I don't notice, that's good enough for me.