About movements

[onzenuub 308]

Found this on RWGcc, writer Ziggy:

Mechanical movement user guide

 

Automatic movements.

 

There are two basic types of automatic watches, those that wind in both directions, and those that wind in one direction.

 

 

Uni-directional winding movements

 

all Asian models are unidirectional (at least the ones I have seen). Included in this is the Asian or ETA 7750, its a unidirectional model.

 

You can safely wind these movements as long as you do so slowly and only enough to get the movement running.

 

 

Bi-directional models

 

ETAs and most Swiss models, 2824-2, 2836-2, 2892-2, etc¦

 

You can hand wind a bi-directional model, as long as you do so slowly, these models have automatic winding clutch wheels with click levers that will be damaged by fast or repeated windings, as above, wind until the watch starts running, then stop.

 

There is no such thing as Over-winding a watch so forget that notion.

 

An automatic watch has a clutch assembly on the mainspring to allow the mainspring to slip once the watch is fully wound. Otherwise the rotor would jam up and not rotate.

 

When you first get your new watch, you should wind it a good 25-50 turns by hand before you put it on. Just follow the cautions above. This will give the mainspring a full wind, and get the watch going with full power available. Once your wearing the watch regularly, it doesn’t need to be wound.

 

 

 

Manual wind models

 

Simple rule to always follow, wind the watch until it stops and you cant wind it anymore. I dont care if it takes 150 turns of the crown, until and unless you have reached the full stop and cant wind anymore, you have not fully wound the watch. The odds of winning the lottery are better than breaking a mainspring from winding, I have only ever seen one broken mainspring, and it was defective

 

Basics on the most common movements

 

ETA, automatics, 2824-2, 2836-2, 2892A2 etc

 

These models are basically the same, automatic wind models, and they all beat at 28,800. Although they are all the same speed, the 2892 series is noticeably smoother sweeping than the others (not that the others are not smooth, but there is a difference).

 

 

Some are old surplus stock and can suffer from dried up sticky oil. The Gold coloured ones are from the ETA factory in Switzerland and the Silver (actually they are Nickel plated) ones are from ETA in Hong Kong.

 

Date set, no problem for quick set on the date, you can do it anytime you like.

 

Power reserve, 36-48 hours.

 

 

 

ETA 6497-1 (misidentified as Unitas)

 

Manual wind, 18,000 BPH

 

Very reliable, has been around in one form or anther for 70 years

 

Power reserve, 46 hours

 

 

 

Asian 7750

 

Chronometer, i.e. stopwatch. Automatic. Not a bad movement, but should be serviced as they are mostly dirty and/or dry (no oil). Once serviced seem to work really well. 21,600 or 28,800 BPH. Some have never been serviced, and have no problems, so its really up to the owner what they want done.

 

Cautions adjust the time on these models only if absolutely necessary. The cannon pinion (clutch between the motion works and the crown) is not very good and can and will slip if overused. Symptoms of a cannon pinion slippage is that the watch will apparently loose time when in fact the cannon pinion clutch is slipping, the movement runs on time, but the hands dont indicate the correct time.

 

Caution, never ever set the date between 7pm and 2am, if you do, you will damage the keyless works.

 

 

 

ETA 7753 (7750 etc)

 

Excellent movement, doesnt need a thing but a good home. Fast beat at 28,800.

 

Caution, never ever set the date between 7pm and 2am, if you do, you will damage the keyless works.

 

 

 

Venus 175 (another misidentified model, sometimes named Lemania 1874 or whatever)

 

Chronometer, manual wind. Good movement, well designed and built, does suffer from jerky seconds hand once in a while. Not bad as delivered, clean, oiled so - so.

 

21,600 BPH

 

 

 

Asian movements

 

Most are automatic and have a 21,600 BPH. Reserve is 36+ hours.

 

Most need nothing, and overall are new and clean and well oiled.

[onzenuub 308]

And some other issues:

Do not activate the chrono until you have done all these steps as mentioned

 

When you receive your watch, please remember to handwind the piece for about 5-10 rounds (very slow and gentle) to generate some power reserve. [if you feel the slightest resistance immediately stop handwinding. The gears are probably dried out and your movement needs some servicing.]

Then you carefully shake the piece for 1-2 minutes to generate more power reserve.

 

How do you set date on 7750 or 7753 or 7750b1 or any movt with date chrono/ automatic?

 

Make sure you do not adjust the date between 10pm-3am ever!!! Always adjust the hands forward and never backwards.

 

Pull the crown out to adjust the hour hand manually to determine when is am/pm. See the date change - then you will know when is am/ pm. Make sure you know when is am/ pm before you proceed

 

After u have confirmed the am/ pm - adjust the crown to get to the desired date you want.

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I would also suggest only adjusting the hands forwards, never backwards. One strange thing I've noticed when adjusting the time on A7750 movements is that the minute hand is very difficult to keep at the adjusted time. Everytime you set it to the correct minute, you pop the crown back in and the hand jumps forwards half a minute or more. Very, very annoying.

 

One last thing to mention is that once you've wond the hands forward and set the time, you always seem to lose a minute. Basically, the first minute after you pop the crown back in is actually 2 minutes, not 1 so the watch ends up 1 minute slow. The way you solve this, and don't ask me why this works, is that you set the time a couple of minutes ahead of the correct time then adjust the hands backward to the correct time.

[oscarmadfish 0]

thanx onze

[iabounty 8]

We would need the "Bristal Stool Chart" to analize my movements....... (Cue John.....) By the way thanks for the great information Dutch. I don't care what everybody says about you, your alright in my book... :wink:

[AllergyDoc 40]

Interesting site for movements. Not complete, but interesting.

 

http://www.pmwf.com/Watches/WatchTools/Gen...reMovements.htm

Edited December 4, 2008 by AllergyDoc

[onzenuub 308]

Interesting site for movements. Not complete, but interesting.

 

http://www.pmwf.com/Watches/WatchTools/Gen...reMovements.htm

 

The link don't work for me Doc.

[alphakazi 0]

working here...

[oscarmadfish 0]

works here

[Massimo 53]

Ziggy is "the man", a watchmaker who knows his reps.

 

Here's some more stuff from him, also copied from RWG.cc, specifically on the myths around the Asian 7750 movement, from July 2008:

 

 

 

 

User guide to the 7750 automatic Chronograph movement

 

Pity the poor 7750, of all the movements, it has to be the one that is discussed the most on these forums, yet it’s probably the most misunderstood and certainly the one movement that everyone has an opinion on. There are so many myths and legends and un-truth’s about this movement, that I though I would share with you those that I remember.

 

Myth or Truth??

 

1. You should run the chrono for 24 hours after you first get your 7750, to help “distribute†the oils…

 

This is totally untrue, not only for a 7750, but for any watch movement. If you understand how a movement is oiled, where it’s oiled, and how the oil is applied, you will know that this is impossible. A movement doesn’t have oil “sitting around†waiting to be splashed and distributed inside the movement when it’s running. When speaking about lubrication in a movement, the type, quantity and how it works is not like any other mechanical thing. It’s certainly not like a car engine, or even the engine in your lawnmower.

 

In a properly lubricated and serviced movement the oil is held in place between the pivot and the jewel via capillary action. If the oil is held in place, then it has no where to go or be distributed to…

 

For a movement to be correctly oiled, it first needs to be perfectly clean and dry. Oiling any movement without a full teardown and starting with a clean and dry jewel and pivot, is another myth. Once you have a perfectly clean and dry movement, a measured drop of the specific type of oil is inserted into each jewel, between the jewel and pivot. The measured drop of oil then gets sucked in by capillary action, and the oil fills in the space between the jewel and the pivot. And there is sits, forever. Once the oil fills the space, it can’t move, or be distributed or anything, capillary action keeps it secured in place. The oil will stay there until the watch is cleaned or disassembled. Time only causes the oil to deteriorate and dry up and in about 5 years (makes no difference if the watch is running or not) the oil needs to be replaced with fresh oil.

 

Since all the oils that are used in lubricating a movement are held in place within the jewels by capillary action, what oil is exactly being “distributed†when you run your chono for 24 hours? The answer of course is “noneâ€.

 

Myth – Busted

 

2. You should only run your chrono with a “Fully Charged or fully wound movementâ€.

 

The friction in a movement is carefully planned. There is a certain designed friction built into each and every movement. Part of that friction is of course the oil type and quantity applied in each pivot and jewel during servicing. If you over-oil, or under-oil, or use the incorrect type of oil when you service the movement, the running of the movement can be affected dramatically. Over oiling a movement can stop it running completely, under oiling can cause over-banking of the balance wheel (spinning to far and hitting the impulse jewel).

 

If the power reaching the balance wheel varies, the balance wheel will swing more or less (more power = larger swing, less power = smaller swing, less swing = faster, more swing = slower). If the balance swings more or less, the rate of the watch will vary, if it varies, the time keeping is not accurate.

 

Therefore the design of the 7750 chronograph, like any well designed movement, is such that the balance wheel can’t tell the difference between a running chrono, and a chrono that is stopped. If the basic movement friction doesn’t vary from chrono ON to chrono OFF, it makes no difference as to the state of wind of the movement when the chrono is engaged.

You can run the chrono at any time, whenever you want, it makes no difference as far as the movement is concerned.

 

Only two things happen when you start a 7750 chrono

 

1. The tilting pinion (which is running ALL the time) tilts over and engages into the center chrono seconds gear. The center seconds chrono gear has slight friction, in fact it’s very free to rotate, any friction would be the actual gears meshing. The only real friction is when the center seconds gear ticks over a “minute†on the 30 minute counter. If your movement is serviced correctly, and the chrono adjustments are all within the specifications, there would be about 2 seconds of actual engagement between the center seconds and 30 minute counter, this quick engagement and disengagement isn’t enough to slow down the balance wheel and affect the rate.

2. The 12 hour wheel wants to run all the time, why? well because it’s connected directly to the bottom of the mainspring barrel. As long as the watch is running, the mainspring barrel is spinning round and round. The reason the 12 hour counter doesn’t run when the chrono is OFF, is because a break lever is preventing it from running. Turning the chrono ON, releases this break lever and the gear starts to spin.

 

That’s it for what happens when you engage the chrono, very simple and easy.

 

So starting the chrono causes the tilting pinion to swing over engaging the center seconds gear, at the same time the 12 hour wheel is released and starts to spin.

 

What does the movement see? Nothing really, it doesn’t know if the chrono is ON, or OFF, because there is no change in the friction or running. So if the movement can’t tell if the chrono is running or shut off, what does it matter as to the state of wind of the actual watch? It doesn’t matter, you can engage and run the chrono any time you like, and even leave it running until the mainspring runs out of power…it doesn’t make any difference.

 

Myth - Busted

 

3. Don’t set the date between 7 pm and 2 am

 

This is true for all 7750’s, Asian or ETA. There are two type of calendar changeover gears, Instant, and Slow.

 

Instant Date Change. A small gear with either a built in moveable spring or a spring connected to it, changes the date “instantly†when it snaps over at midnight.

 

Slow Date Change. A fixed gear rotates along with the hour gear and slowly engages into and switches the datewheel. Since this gear has a fixed tab that engages into the Datewheel, if you try and change the date when this tab is engaged into the Datewheel, you will damage the Keyless works. It’s not a design defect, it’s just the way it is on this model, if you want a date function, the size of the movement only allows a certain type of date change gear, in the case of a 7750, a fixed gear is installed.

 

The date gear starts to engage with the date wheel around 7pm and disengages totally by 2 am, if you attempt to do a quick date change during the engagement, you will damage the watch.

 

Myth – Confirmed

 

4. The Rotor on my 7750 is noisy

 

The 7750 rotor only winds in one direction. The winding direction has resistance since the rotor is trying to wind the mainspring. In the other direction there is no resistance at all, and the rotor is free to spin around, and around…and around… If the rotor bearings are dry, there is nothing preventing the rotor from spinning like crazy. Lubricating the bearings helps to quiet the rotor and prevent such a free spin in the non-winding direction.

 

The noisy rotor is normal, it can be made quieter during servicing when it’s lubricated, or you can lubricate it without a full service.

 

Myth – Confirmed

 

5. Don’t re-set the chrono with the seconds hand anywhere but between 10 and 2 on the dial

 

On an un-serviced 7750, the reset hammer slams down very hard onto the heart cam’s for the Seconds and Minute counters. This force can and will cause the seconds hand to slip, if the hand is sitting anywhere but between 10 and 2. Even genuine watches can suffer from this problem. A slipping center seconds hand is totally preventable by the owner, all you have to do is never reset your chrono between anything but 10-2.

Myth – Confirmed

 

I think that’s about what I can remember, if you have any further items that you think should be added to this list, please let me know and I will address them.

 

And as always, all of this is based on my personal experience with these movements as well as standard knowledge with movements and their servicing.

 

Thanks for reading.

 

RG

[P_Diddy 0]

I want to put my Asian 7750 movement in my Ebel on watchwinder.

 

Which direction does it wind, clockwise or Anti-clockwise?

 

 

The 7750 rotor only winds in one direction. The winding direction has resistance since the rotor is trying to wind the mainspring. In the other direction there is no resistance at all, and the rotor is free to spin around, and around…and around….

[Massimo 53]

I want to put my Asian 7750 movement in my Ebel on watchwinder.

 

Which direction does it wind, clockwise or Anti-clockwise?

 

 

The 7750 rotor only winds in one direction. The winding direction has resistance since the rotor is trying to wind the mainspring. In the other direction there is no resistance at all, and the rotor is free to spin around, and around…and around….

 

I have my winder set to wind clockwise and it winds my 7750 IWC.

[houndoggie 58]

We would need the "Bristal Stool Chart" to analize my movements....... (Cue John.....) By the way thanks for the great information Dutch. I don't care what everybody says about you, your alright in my book... :wink:

 

 

I have the Bristol stool chart hanging in my employee bathroom on the back of the door along with all the other Labor Law posters....

 

Funny Shit.

[onzenuub 308]

We would need the "Bristal Stool Chart" to analize my movements....... (Cue John.....) By the way thanks for the great information Dutch. I don't care what everybody says about you, your alright in my book... :wink:

 

 

I have the Bristol stool chart hanging in my employee bathroom on the back of the door along with all the other Labor Law posters....

 

Funny Shit.

 

 

DAMMIT

[whaler 17]

Helpfull post and a good read for noobs!