Replacement cylinder parts?

[bil2054]

Anybody know a source of replacement parts for a Swiss cylinder escapement? My Diogenes watch has a busted cylinder, the lower plug is gone, and the contrate wheel has broken teeth. Oh, and a balance spring will probably come in handy, too.
I have another movement I could scavenge parts from, I think, but I have hopes of getting that one going as well.
Thanks.

Bill Miller
NAWCC Member #157710

[bil2054]

Anybody know a source of replacement parts for a Swiss cylinder escapement? My Diogenes watch has a busted cylinder, the lower plug is gone, and the contrate wheel has broken teeth. Oh, and a balance spring will probably come in handy, too.
I have another movement I could scavenge parts from, I think, but I have hopes of getting that one going as well.
Thanks.

Bill Miller
NAWCC Member #157710

[Steve Maddox]

Bill,

There shouldn't be a "contrate wheel" in a watch with a cylinder escapement. Those are typically found in watches with a "verge" escapement, and they're the wheel with teeth cut on the edge that drives the horizontally mounted escape wheel. I believe the wheel to which you're referring in the cylinder is simply the escape wheel.

S. LaRose used to offer assortments of cylinder escapement parts, including complete cylinders and escape wheels, and I'd bet they're still available. They might have balance springs as well, but I've never tried to order any of those. In any event, the chances of pulling the particular parts you need from an assortment are hit and miss, and your best bet might be to get them from another movement -- especially if you have an extra on hand that you think might work.

If you replace the entire cylinder, be sure to mount it the same way the old one was in the wheel, and be sure that the limiter pin is in the right place on the balance rim to prevent the wheel from taking more than 180 degrees of motion in each direction. When the balance in a watch with a cylinder escapement takes too much motion, the cylinder will lock-up on the escape wheel, and if one forces the balance wheel backward, it'll break a tooth off the escape wheel.
-----------------------------

Steve Maddox
President, NAWCC Chapter #62
North Little Rock, Arkansas

[bil2054]

Thanks, Steve, I will give S. LaRose a try!
On the subject of a contrate wheel, Britten describes it as "A toothed wheel whose teeth are at a right angle to the plane of the wheel", and H. Harris in his "Handbook of Watch and Clock Repairs" specifically refers to the escape wheel in a cylinder movement as "a contrate wheel".
By the way, I was doing some research on the net for "cylinder movement" and was rewarded with a patent application for a self lowering toilet seat. Ain't technology grand? :smile:

Bill Miller
NAWCC Member #157710

[GandalfPC]

That wheel is the escape wheel of the style used in cylinder escapements.

Jason Goldman
Apprentice Watchmaker

[Steve Maddox]

Bill,

Check out the sketch of the "verge escapement" in the back of the Shugart book, in the "Watch Terminology" section. That will describe things much better than I could with mere words. You might also want to check out the sketches for the terms: "contrate wheel," "crown wheel," and "cylinder escapement."

The escape wheel for a cylinder escapement is very distinctive, but it's still an escape wheel, and it's very different from a "contrate" wheel.

SM

[bil2054]

Thanks, Steve. I went back to Harris' book, and see that I misread his description. The particular movement he describes has a contrate wheel which engages the pinion of the escape wheel. So, although a cylinder escape wheel is contrate in general form, it would be kinda confusing to have two contrate wheels in one movement. :redface:

Bill Miller
NAWCC Member #157710

[Steve Maddox]

Bill,

There's still an essential point you're missing. A "contrate wheel" has teeth whose functional surfaces are cut at right angles to the plane of the wheel. In a watch with a fusee escapement, the contrate wheel changes the plane of rotation of the escape wheel from vertical to horizontal.

Essentially, contrate wheels are designed to make a gear train turn a corner.

The escape wheel of a cylinder escapement has offset teeth, but their functional surfaces are parallel to the plane of rotation of the wheel. They do not alter the plane of rotation the way contrate wheels do.


SM

[bil2054]

No, Steve, I understand the principle well enough that I can't believe I made the mistake in the first place. As I mentioned, I misread Harris' description, but I didn't say how large an error it was; you see, Harris was describing the cylinder escapement in a carriage clock, which does need a 90 degree vector change. I was just breezing through, and landed on the escapement part, and totally ignored the context.
I appreciate your effort to save me from dumb mistakes, though; I can make 'em! :biggrin:

Bill Miller
NAWCC Member #157710