I'm pretty new to watch collecting, but it seems that when I wind several of my automatics that have wound down completely, I need to do about twice as many turns until I hear the ratchet as for a non-automatic to be fully wound. Is the manual wind gear train of automatics significantly different than for a non-automatic?

 

usually in automatic watches there's a safety device so has not to break the spring. Si you can wind them endlessly, well, if you have time to do so

 

Mechanically, the manual wind system is a bit different because the automatic system and the manual system are interconnected. But the hand wind function works pretty well the same, with differences with the ratchet system. The biggest difference between the automatic and manual winders is the mainspring and the mainspring barrel. To prevent overwinding, the automatic mainspring is fitted with a calibrated clutch that begins to slip once the spring is fully wound. This prevents over winding of the automatic. Typically, about 30 to 40 turns of the winding crown on an automatic is enough to wind the mainspring fully. As to “hearing” the ratchet system on an automatic? Most automatics made little to no sound as manual winding happens. You might be hearing the clutch on the mainspring slipping. Mostly, you hear a “whirring” sound as you manually wind an automatic.

 

Right, not the ratchet. I meant that I wind the auto until, listening carefully, I first hear the clutch. It just seems to take many more turns than fully winding a manual.

 

A number of factors would come into play on both an automatic wind and a manual wind watches as regards how many turns of the crown would be required to wind the watch fully. Size of watch, size of mainspring barrel, length of mainspring, gear ratios in the winding apparatus, etc. Such factors would also affect run time from fully wound to run down, one model to another. Longer to wind might mean longer run time. Quicker to wind could mean shorter run time. Some automatics actually have recesses cut into the mainspring barrel wall, and others don’t. You can often hear the mainsprings slipping on the ones with recesses, when you can’t hear the slipping bridle (clutch) on ones with a smooth barrel wall.

Antique watches often have a run time of 36 hours or less. Some modern watches have run times of 48 to 52 hours or more. And some ultra-modern ones have a run time of up to a week. I have an Omega a Speedmaster that takes 60 turns from run down, but the run time is about 48 to 52 hours. So it is difficult to make objective comparisons in this regard.

 

My manual wind SLAVA has twin mainspring barrels connected by an idler gear. Its extremely easy to wind and has a minimum 42 hour run time.

It seems the longer the effective spring length the easier to wind and the longer the run time.
With dual mainsprings each spring can be much lighter than standard mainsprings yet working together they deliver more torque to operate the mechanism and any complications.

I suspect the springs would last much longer as well.

 

I get paranoid about over winding the manual ones and probably end up under winding them. I know you get a feel for the watch but then I rotate through the collection and I’m like “is this the one that only winds 22 times or is the one I can wind 40 times?”

 

I'm wondering how many people actually count the amount of turns on their manual wind, I just go by feel.

 

Not necessary, and I wouldn't fret over it. In fact, continuing to wind it up fully will eventually teach you to develop the feel to discern when enough is enough. There will be a little increase in resistance, and then it will stop. No need to force it, and no harm done.

 

Terminology clarification needed: what do you mean by "gear train"? The mechanism from the crown to the barrel? That's called the keyless works. The wheel train is a series of gears that starts with the mainspring barrel and goes to the escapement.

Watches have different ratios in their keyless works. It's not just a difference between auto and manual winding. Sometimes the ratios are identical if there's a manual wind and automatic wind version of the same caliber (like the Longines 19A series automatics and 8.68 series manuals, or Omega 55x/56x automatics and 600 series manuals.)

The ratios in the wheel train are indicated by the beats per minute the caliber runs at.

 

I suspect very few can actually judge a full rotation when winding. I know I can't and the case design of some watches make it pretty much hit or miss in turning the same amount with each move of thumb and finger.

What seems like 60 turns may be 45 full rotations for one watch and 35 for another.