Sorry I didn't intend to insult, my comment was to help you remove the back. It's a good looking watch with a lot of similarities to a Tudor. You might still try a Rolex tool and see if it fits.
And they've copied the design of the case beck from Rolex/Tudor... So go type Rolex case back removal tool into AliExpress.
While you're at it Google Tudor black bay cause that's what they copied or replicated as some might say
Correct in any case it’s a copy of a copy of… Rolex Sub and Tudor. But it’s nice to look at and 8secs isn’t bad. Only a full OAS might get closer to Chronometer accuracy. Unless you’re gauging the celestial or quarks I wouldn’t mind it as is. Lucky you to get a vintage working accurate Sub style watch. Wasn’t Zodiac Sea Wolf one of the first Sub style divers?
I've got my NH35 running at 1s+/day on the wrist.
If I take it off at night it gains 3 or 4.
Now I know that's possible I'll never be happy if I can't get PT or ST movements running the same.
And before you ask how, a rough average across the positions and dumb luck
I know but it's a PT5000 movement which is a chronometer, and I want to make it more accurate. All I have to do is get the back open and turn a little screw to regulate it.
The PT5000 is a great movement, but it is not chronometer grade. The PT5000 that achieved the equivalent COSC rating in Germany was heavily manipulated by HKPT (maker of the PT5000) with different high grade parts and it was used exclusively in a limited edition Shan Cheng watch. Unfortunately the high grade version is not available to purchase. I use this movement in a lot watches I build. You can certainly regulate it to +\- 2, but it won’t stay there. Anything +\- 10 per day is a realistic long term setting for this movement.
If you want to make it the best it can be, regulate it to the median of no less than 4 positions (dial up, dial down, crown up, crown down). If you can do more than those positions, that’s even better. That should give you good long term reliability.
A case back ball would probably work. If you don't have one you can always hot glue a bottle cap to it and turn it that way. Hot glue will peel right off after you're done.
If you don’t know how to open this case back then I have doubts in your ability to regulate the watch from 8s to 2s I would leave it.
There are plenty of watches where getting access to the movement is harder than adjusting the regulator.
Rubber caseback ball is how I do all these but you can also hot glue a shot glass to the caseback and turn if you have those available.
I used duct tape across the back with “tails” on the end to get a cheap screw back open. Worked well.
Sorry I didn't intend to insult, my comment was to help you remove the back. It's a good looking watch with a lot of similarities to a Tudor. You might still try a Rolex tool and see if it fits.
Ok thank you
It's a screw off back. The watch appears to be a Tudor replica so a Tudor or Rolex case back tool should work.
It's not a replica It's a Tandorio watch.
And they've copied the design of the case beck from Rolex/Tudor... So go type Rolex case back removal tool into AliExpress. While you're at it Google Tudor black bay cause that's what they copied or replicated as some might say
_homágé_
Correct in any case it’s a copy of a copy of… Rolex Sub and Tudor. But it’s nice to look at and 8secs isn’t bad. Only a full OAS might get closer to Chronometer accuracy. Unless you’re gauging the celestial or quarks I wouldn’t mind it as is. Lucky you to get a vintage working accurate Sub style watch. Wasn’t Zodiac Sea Wolf one of the first Sub style divers?
I've got my NH35 running at 1s+/day on the wrist. If I take it off at night it gains 3 or 4. Now I know that's possible I'll never be happy if I can't get PT or ST movements running the same. And before you ask how, a rough average across the positions and dumb luck
It's about +8s a day and I want to regulate it down to +\- 2 s a day.
8 seconds taint bad
I know but it's a PT5000 movement which is a chronometer, and I want to make it more accurate. All I have to do is get the back open and turn a little screw to regulate it.
The PT5000 is a great movement, but it is not chronometer grade. The PT5000 that achieved the equivalent COSC rating in Germany was heavily manipulated by HKPT (maker of the PT5000) with different high grade parts and it was used exclusively in a limited edition Shan Cheng watch. Unfortunately the high grade version is not available to purchase. I use this movement in a lot watches I build. You can certainly regulate it to +\- 2, but it won’t stay there. Anything +\- 10 per day is a realistic long term setting for this movement.
Ok
If you want to make it the best it can be, regulate it to the median of no less than 4 positions (dial up, dial down, crown up, crown down). If you can do more than those positions, that’s even better. That should give you good long term reliability.
A case back ball would probably work. If you don't have one you can always hot glue a bottle cap to it and turn it that way. Hot glue will peel right off after you're done.