My watch has a Seiko Nh35a automatic movement, it gains about 1 minute every seven or eight days, Is this normal ? I'm new to autos and I understand they are not quartz accurate.
It would be quite normal.
I would have an auto seiko movement which loses 60secs every 2 days.
I always assumed the better quality movements in more expensive watches would be much more accurate though.
Yes that would be acceptable.The trick is to buy enough seikos that you never wear one long enough to realise how poor the time keeping is ,One for each day of the week was my original target but I’m getting closer to one for each day of the month.
Or you could have one regulated.
The 4r36 in my new prospex was about 15 secs a day fast. Its essentially the same movement as yours mondeo. 15 secs is within the very broad specs quoted as acceptable by seiko, but they can be nudged to far higher accuracy if in good repair, unmagnetised and regulated.
I regulated it to zero spd face down, wore it for a day, noted the loss of seven seconds a day and advanced it same.
If I leave it face down over night it gains back the 2 or 3 seconds its losing a day being worn. Since doing this 28 odd days ago my watch has been to the second accurate every morning. 0 seconds per month. I'd say I'm rather happy with my little ol seiko in this regard.
In short, I'm using the positional variance in timekeeping to my advantage.
If you're in the Cork area I can do this for you foc.
Generally speaking, I have found nh34(5)(6) etc when new and unmag'd, beat error set to 0 and reg'd to +7 tend to be - 2 secs a day when worn. I have 3 examples all identical like this.
Yes you get what you pay for. The Seiko's have massive tolerances in their specifications. Having said that they are not a bad movement, just cheaper. Lots of much more expensive watch makes use seiko or other similar brand movements. Just checked my Aqua Terra and it's -3 seconds per day and zero beat error with the face up. You can get it adjusted which for a watch maker/repairer is an easy enough job. Wouldn't recommend trying it yourself though. Surefire way to really mess up.
The good thing about the seikos movements I mention is they are diesels. A high beat movement is the candle that burns brighter alright, but these are affordable and have imo struck a good balance.
I am in the process of buying a Swiss high beat movement for a project and am in the planning stages at the moment. Interested to see how the other half lives and will enjoy the smoother second hand sweep:)
To the OP: yes, the movement could be just fine, but still run in the +8s per day range.
Just get it regulated. Not a major job.
Just needs a bit of time on timegrapher.
Or, there are apps that can do the same thing with your phone.
Do a search for same and you'll fined apps and how-tos on it.
Or, bring it to an horologist.
the highbeats are lovely.. can be quite accurate as well.. ive seen seiko high beats that are practically 0 seconds per day.. and same for non high beat.. but also seen them 5, 6, 8 seconds a day out.. everyone has different tolerances for this.. once ive seen it can be so accurate it annoys me when i get the same movement in another seiko etc and its out (especially if its a 3k plus watch).. few of the omegas ive had have been just a coupe of seconds a day out.. and the datejust i had was pretty close to bang on.. i don't have a timegrapher but easy to keep an eye on if you wearing couple of days in a row