I recently acquired a Watchco SM300 with a cal. 552 movement and noticed that the second hand doesn't sweep smoothly, but rather it seems to go in very short and fast increments. I just figured the cal. 552 would be a bit smoother and not so choppy. Not sure if you can even tell from the vid. It's more obvious in person. (Be sure to enlarge the vid to see it better). Are all 552 movements like this, or do I need a servicing? Thanks
Can't see the video, but what you're refering to is called stutter. It happens when the pressure on the indirect seconds mechanism is incorrectly set.
I was under the impression that it ticked once for every two beats, so 28,800 beats at 4hz, and 19,800 being 2.75hz. Chronographs with 28,800vph tend to have intervals on their chapter ring for 4 quarters per second, rather than 8, I could be wrong, but that's how I thought it worked.
Once every beat so each turn of the balance wheel in either direction equals one tick. One hertz is a complete cycle, which is one rotation in each direction, or two ticks. So 19,800 bph = 2.75 hz = 5.5 ticks per second.
Ahk, I thought the hz rate was also the rate it ticked at, anywho it does look the same as my SM300 did in the video
This discussion on bph and hz rates is a bit over my head, so what's the consensus then — that the stutter effect is normal for this particular movement, or it should be smoother and needs to be serviced? Thanks
It is very hard to see from your tiny video, but I think what you are actually talking about is that it pauses for an instant twice on the video? If that is so, no that is not normal.
No, those two pauses are likely glitches in video playback. You really need to expand the video to full screen to see the actual movement.
Well then, if you are refering to the regular ticks, yes that is perfectly normal. No spring watch secondhand is truly "smooth" as you say.
I realize that, but I just had a Steinhart where the seconds hand was WAY smoother - not choppy at all. I would just think an Omega movement would be at least as smooth as a Steinhart. Don't get me wrong, I sold the Steinhart and kept the SM300 for a reason. But I did notice a definite difference in the smoothness of the seconds hand between the two, and it made me wonder if the SM300 should be similar. Just want to be sure it's not a problem or needs servicing, that's all. Thanks
Looks normal to me. The only ones which I know have a smooth sweep seconds are those of the Grand Seiko Spring Drive.
Or an Accutron or Omega f300 or other Swissonic, which sweep - there is no discrete tick visible to the eye. Your Steinheart was probably a 28800 bph and would appear smoother at 8 ticks per second over the 5 ticks you are getting from the old 18000 Omega. A HF watch at 36000 is getting noticeably smoother to the eye.