I was just browsing on Northern Partners website and read" Most pocket watches will not keep good time hanging on a hook" as in a display case --what do you fellows know about this because that is where mine are and some run excellant same as on there back or belly-- others not so- thanks BOB McK

They might have a point to a certain extent, if the watch is a light movement/case combo the action of the balance wheel is enough to cause some movement which would take some energy away from the balance action.

On some watches I have like 16/18 size that have good strong balance action on a polished surface laying on it's back I have seen the watch move back in forth in response to the balance action, so you could say the same thing about a watch laying on its back too.

I doubt that the energy loss is that dramatic but it could cause some timing changes. If the watch is heavy enough and you don't see the watch swinging when it is hanging on the hook I doubt that it is an issue.

I put a small piece of leather between the hook and the bow of the watch, essentially damping any motion what so ever that the balance is causing in its swing. No problems at all.

I hang all my 'rotation/carry' watches overnight.

I agree with Claude...I've never seen a heavy 18s watch move on a hook, but I HAVE see 16s watches swing, and quite vigorously. That's when I started trying the piece of leather, and it stopped all that nonsense.

Regards! Mark

I guess the easiest way to ponder this topic would be to think of how hard/far you could throw a football wearing cleats on good solid ground and then how far you could thow the football wearing roller skates. The principle is about the same but the roller skates would be a bit more dramatic.

Using a wrap of leather that is more than a 1/4" wide would be enough to stop the pivot action that the watch would have just hanging on the hook because the contact area on the hook and bow would be quite small where the leather strap would be enough not to be a pivot point.

As Mark mentioned I was quite surprised by watching a BWR 571 dance on its back quite vigorously on a polished table. Beside the worry of wear to the case I figured it would also impact timing so I will put it on a rubber coaster if I leave it on the back for any length of time which stops that action.

I have seen size 12 watch rock back and forth on a hook.

Robert,

The phenomenon is called 'reduced mass'. Typically a mechanical pocket watch hanging on a hook will gain time due to the effect of 'reduced mass'.

Here is an explanation I posted earlier in another thread:


"The reason that a watch hanging on a hook gains time is because of a phenomenon called 'reduced mass'. A watch movement and case will rotate in the opposite direction of the balance wheel, thus effectively shortening the swing arc of the balance wheel and allowing the watch to gain time. In other words, the hairspring is pushing or pulling the balance wheel in one direction and the movement and case in the opposite direction."

"So, to reduce the amount the case and movement 'recoil' they need added mass (weight) in addition to their own. Carry the watch in your pocket and your body becomes the added weight. Lay it on a table with a non-slick surface and the table becomes the added weight etc., etc."

"It is exactly the same effect as the recoil of a gun, thus you can say your watch is 'recoiling' in your pocket with each swing of the balance wheel."


It doesn't seem possible, but that little hairspring (not the mainspring) is doing all the pushing and pulling and causing your watch to swing back and forth on it's hook, the little devil.

Joe

Actually the watch can go into a "harmonic" rotation for a few degrees back and forth in reaction to the torque shock imparted to the balance wheel from the pallet fork via the roller jewel on the Balance wheel.

As Pete mentioned, it will happen because the "flick" of the pallet fork is actually strong enough to "rock" the watch in a pendulous or radial fashion when the watch is hanging from a hook or sitting on a smooth surface face-up.

As this is a harmonic, it could take 5 or 10 seconds to build up visibly , but its motion is in direct reaction to the pallet fork meaning the "flick" is partly absorbed to the watch movement and case, leaving less to propel the balance wheel, hence a shorter arc of rotation of the wheel causing a timing error.

I think a lot of the time the swinging is caused by a worn bow.

I use a leather strap on my carry watch to reduce wear on the bow. Having had a bow come loose when the watch was hanging from a hook I avoid hooks, but I cannot recall any time keeping problems for 16 and 18 size watches hanging from a hook.