I have 4 Hamilton 974, 16s, and upon checking every one of them has the same problem. The watch may be useable but I would always know it's there. Not really visible to the naked eye it shows up well on a microscope. Cracked drum bridges. On all 4 of them.

Patrick, I've never looked for cracks but will next time I have one apart. Are they evident in other grades I wonder?

Patrick,

I'm confident that what you're seeing here aren't cracks but instead marks caused by the center wheel recess being cut subsequent to that of the third wheel. Obviously both couldn't be milled at the same time since they overlap, and these marks are evidence of the third wheel recess being milled first ...or at least milled to a slightly lesser depth if the center was milled first. If these marks appeared on the finished side of the bridge, I'd be very surprised.

William

Agree with William on that one.
as Im working on one plate that got over cuts.

I have thoroughly checked it out on all the bridges, using a 50 power microscope, doing my darnedest to prove you are wrong, but I must admit I do believe William is right. There is a slight ridge there, more pronounced on some, the lip (Height) is smooth as is the top side.
Patrick

I have thoroughly checked it out on all the bridges, doing my darnedest to prove you are wrong, but I must admit I do believe William is right. There is a slight ridge there, more pronounced on some, the lip (Height) is smooth as is the tip side. Williams circle he drew kind of spells the story plainly.
Patrick