A Reliable Seconds @ 6 Movement?

[Ronin]

I have a few budget late model Daytona's that I figured I would experiment on.

There seems to be 3 common types available from a movement perspective:

1.) The A7750 versions with working Chrono

2.) A "21J" type with faux chrono's that perform, date @ 3, 24hr @ 6, week day @ 9 and an ALWAYS sweeping center seconds

3.) A "21J" type with faux chrono's that perform, date @ 3, "Jeweled" SECONDS @ 6, week day @ 9 and an ALWAYS sweeping center seconds

It is that 3rd one that got me curious. I am more after the "look" or should I say eliminating the huge "tell" (faux chrono, always running center seconds) from these cheap 21J versions. I am also NOT concerned about a working chrono. If I need a "working chrono" for the day, I grab my Ebel, Swiss Army, etc, since I am leery to even "use" an A7750.

Ok, here are some photos. The plan is simple: Freeze everything except for the Hour, Minute and Seconds @ 6. So far freezing the 3 & 9 look easy. The real question becomes the center seconds. (Please chime in experts, since I am NOT).

Thoughts, questions, comments, snide remarks welcome...

[jmb]

I have had the same thoughts as I have one with your scenario 3 movement. So far I have not had the time...

[Francisco]

to freeze central second you have to disassemble the movement...so it is not going to be easy.

I think it is an easier approach to freeze the running seconds in the 7750 movement.

Regards,

Francisco

[jmb]

Yes, but freezing the seconds hand on the a21j, and having the seconds at 6 still running, would look more "correct".

[automatico]

I took one of the DG day/date 'chronograph' movements apart with running seconds at 6 and modified it. Freezing the hands at 3 and 9 was no trouble.

A little trouble comes when you freeze the sweep second hand.

Since the sweep second pinion is outside the main wheel train (aka indirect seconds), it does not matter if the ss pinion is turning or not. I cut the spokes out of the wheel that drives the ss pinion and cemented (epoxy) the ss pinion gear to the bridge along with a wedge shaped piece cut from the wheel that I removed...meshed with the ss pinion gear to hold the ss pinion in one place. Quick and dirty but it worked.

You will need to be careful when mounting the center second hand because too much pressure will dislodge the cement and the ss gear.

My running second hand at 6 movement has a jewel on the idler wheel (like the one in the pic) and one on the drive wheel but in reality, the wheel the second hand is mounted on does not have a jewel or anything...it just turns on the plate with support on only one end (known as a 'flying' wheel).

I put a little 'Dri Slide' lube (molybdenum disulfide in suspension) on the second hand wheel bearing and it has worked Ok for months although I do not wear it that often now. I kept it running for a few weeks after it was first modified and the hand worked fine and the watch kept good time. There is almost no load at all on the seconds at 6 wheel so it should be all right.

My advice to anyone who is handy with watch tools is to just take one of these movements apart and look it over. It is easy to see what needs to be done to freeze the center ss hand and hands at 3 and 9. You can also look at a Plain Jane DG without the day/date in 'chronograph' configuration at 3 and 9 to see how to freeze the center sweep second hand. They all have the same indirect center sweep second drive.

note:

The DG movement I worked on was gold color and a bit better finished than the one in the photo and iirc it had 8 or 10 screws in the plate that is screwed to the front of the movement. It had a similar three wheel drive for seconds at 6 though.

Tips:

While the movement is apart, it might be a good idea to take time to clean and oil it properly, especially the balance jewels and pallet jewels. Mine had very little oil anywhere. It was clean though.

If you just want to oil the movement without cleaning it...oil the wheel train pivots and mainspring arbors, then remove the balance jewels and clean and oil them. One quick way to clean balance jewels is to swish the hole jewels around in 'One Dip' hairspring cleaner etc and set them aside to dry. Next...clean the cap jewels in One Dip and rub them on a clean business card etc to remove all the old oil and dirt making sure the cap jewels are pivot side down.

The pivot side will be perfectly flat and the outer side will usually be slightly domed.

Many times a movement will not run correctly after cleaning and the only problem is a speck of hardened dirt/oil on a cap jewel.

Oil the pallet jewels/escape wheel and give it a test run.

If you are feeling extra froggy...oil the reverser and mainspring.

When opening Incabloc gates...place a small bit of clean Rodico over the edge of the jewel or hold the center of the jewel with a sharpened piece of peg wood so the cap jewel will not go in orbit...then remove the whole thing at one whack (cap jewel and hole jewel/setting), with Rodico.

I made a few different diameter tools for removing spiral locks out of a piece of round plastic with a dimple in the center.

You can oil the cap jewel while it is stuck on a pointed piece of Rodico and gently lower it onto the hole jewel and setting or you can oil the cap jewel with the pivot side up and place the hole jewel and setting down over it. Holding the cap jewel still with tweezers while oiling it is a bit tricky and sometimes the jewel will shoot into outer space.

After oiling the cap jewel while stuck on a point of Rodico...set the cap jewel into the hole jewel/setting, then hold the cap jewel in place with tweezers or sharpened peg wood and gently pull the Rodico away. If you foul up, just wipe the oil off the cap jewel on the card, oil it again, and try one more time.

On DG/Miyota type movements...put the train wheels in place with the balance assembly removed or you will not have much room to move them around to line them up. Lining up the train wheels, reverser, and intermediate wheel all at once is bad enough without having to worry with the %&##*** hairspring and balance wheel.

Good luck!

[Ronin]

Automatico! Great information!

Question. To access the Center seconds components they are on the bottom (balance side). As you can see in the photo I removed one top plate, and it looks like there are 2 more screws topside (1 to the left of @6 seconds, and one under the @3 wheel.

[automatico]

You need to remove the autowind assembly to expose the center sweep second drive.

Next, remove the center sweep second hand and ss pinion tension spring, then remove the ss pinion.

The Sea-Gull ST16 is similar to the Miyota clones (DG/CH etc), but a lot easier to work on because of the Seiko type autowind.

Here are some good ST16 pictures and info:

http://forums.watchuseek.com/showthread.php?t=312588

[freddy333]

As long as you are freezing subdial hands, why not just find a standard 3-hand movement (with separate running seconds at 6 that matches the location of the Daytona running seconds) & install (cement) the 2 additional subdial hands in the appropriate locations on the dial? Seems like that would achieve the same effect with alot less work.

[automatico]

"As long as you are freezing subdial hands, why not just find a standard 3-hand movement (with separate running seconds at 6 that matches the location of the Daytona running seconds) & install (cement) the 2 additional subdial hands in the appropriate locations on the dial? Seems like that would achieve the same effect with alot less work."

It would be nice if Eta made an affordable movement that would work but I doubt they do.

The catch is that the center sweep second drive has to be outside the wheel train so you can freeze the center second hand without stalling the movement.

Very few modern movements meet this requirement.

Since these 'chronographs' come with everything you need, it is a straightforward job. After doing 2 or 3 of them, you can fly through this modification with very few false moves.

Cleaning/oiling the movement takes longer than freezing the hands.

[Ronin]

Thanks again, I will keep everyone posted.

@Freddy333, I poked around Ofrei's site for a movement as you mentioned in the past. Not much luck.

[zafod]

Is there anyone who is competant with watches (and in the UK) willing to freeze my centre sweep hand?

[zafod]

Is there anyone who is competant with watches (and in the UK) willing to freeze my centre sweep hand?

I guess not then

[mexrolex]

For this to be a real alternative, the factories will have to do this and then the dealers can sell it. I'd buy one!

[Dizzy]

I would be happy with taking a 21j and freezing the center seconds and having no seconds hand at all... I've always wanted a daytona, but after my sec at 6 died after a few days, i really dont want to buy another one until a solution is found.

How close is the v23 subdial spacing compared to the zenith sec at 9? I wish it was as easy as tossing in a V23 and getting a gen sec at 9 dial...

[automatico]

"I would be happy with taking a 21j and freezing the center seconds and having no seconds hand at all... I've always wanted a daytona, but after my sec at 6 died after a few days, i really dont want to buy another one until a solution is found."

I had a running seconds at 6 'sudden death' Asian 7750 model and it was the reason I decided to freeze the DG center second hand. The dials and cases apperar to be identical comparing the DG powered model to the 7750 model...except the DG case does not have a groove for case clamps and uses a plastic spacer.

The 7750 model claimed to have a sapphire crystal and the DG model made no claims.

The modified watch mentioned above still runs just fine (I wore it yesterday), so I guess it was a pretty good fix. You need the model with running seconds at 6 if possible to make it more convincing.

As far as I am concerned...the best solution would be a quartz chronograph movement with the same sub dial layout and running seconds at 6 ticking 4 to 6 times a second (sub second hands are hard to tell if 21600 or 28800 bph).

I bet a guy could get rich making quartz replacement 3035 and 3135 spec movements for genuine rolex watches with 6 or 8 ticks a second like the new Bulova Precisionist.

My guess is most modern rolex owners do not give a hoot about mechanical movements...just the name on the dial.

Imho, the oysterquartz bombed because it did not look enough like a rolex...and cost 2 arms, one leg, and a left nut to get fixed.

http://watchcomplications.com/?p=43

[marcoxxx1984]

I cannot see new omega chrono with proper subdial spacing for a 16520... it could be so easy to swap this new 7750 to daytona cases....

WHY DON'T THEY DO THIS???!!!!