August 03, 2006, 11:06
John JohnstonQuestion on Howard 17 jewel's movement
I found this movement on ebay and I thought that there was a strange star looking thing on the winding wheel and I was wondering if anyone has seen something like this before?
John
August 03, 2006, 11:19
Cooksey ShugartStop works system used to prevent the barrel from being over wound. So called Maltese cross.
Cooksey
August 03, 2006, 13:13
Tom McIntyreIn the example shown it is missing the finger that is fixed to the barrel arbor. These are often partial like this because they require the watch to be set up properly and sloppy watchmakers couldn't be bothered. The mechanism is called a Geneva mechanism. The star wheel itself is called Maltese cross as Cooksey said. Of course this "cross" has 6 arms instead of 4.
Here is an intact 21J HC movement (click to make it big):
Here is another 17J that is complete.
August 03, 2006, 14:03
John ArrowoodI have seen the Geneva stop mechanism on clocks as well. In fact, I have a Kroeber kitchen clock that has part of the mechanism on the front plate. Someone was too lazy to replace the complete system when the movement was disassembled. This is on par with leaving off the whip spring etc on a watch regulator. "Don't need that, pitch it out and forget it."
August 03, 2006, 23:18
Tom McIntyreMany higher grade and some pretty ordinary clocks have them. There is a variant on my Bingham regulator and a pretty standard one on my Seth Thomas small 8 day shelf clock. It actually has them on both time and strike.
The form found on these watches is a "floating Geneva" which is a little unusual. On most such mechanisms the index finger turns and indexes the Maltese wheel once on each turn as the item is wound. Here the barrel turns and carries the Maltese wheel around during winding and the finger action takes place while unwinding.
It will work ones head a bit to try to visualize it. The clock versions are much simpler since the Maltese piece is fixed to the plate.
August 03, 2006, 23:46
Cort MooreYou are right Tom because this one did "work my head"as you put it. I've "set up" many Geneva stopworks and Reed's barrel pat. is familiar territory but this pattern looked really strange at first. Also, I'd never seen one on this type of Howard before that I can recall. Would these be considered a fairly uncommon feature(i.e. seldom seen/scarce/rare) on the Keystone Howard's?
-Cort
August 04, 2006, 10:43
Tom McIntyreCort, I think they may have found their way onto about 5% to 10% of the 17J OF thin models. They are generally earlier. I would consider them scarce.
Since the 21J thin model is itself scarce, the floating stop works may even be rare there. Actually this is the only 21J HC example I have seen with or without the stopworks.