Take a look at the three scans shown below and see if you can tell what is so odd about this Model 1883 Waltham movement?

http://static.flickr.com/75/154335858_deabac13ca.jpg

http://static.flickr.com/75/154335857_05f988f498.jpg

http://static.flickr.com/76/154335856_9b79deb92c.jpg

Well, there is a pattend date on the underside of the top plate, and something that looks like an extra banking screw. Could it be some type of hacking mechanism?

I'd love to see the "rest of the story."

Wow Mike, you're quick!
There are actually three extra holes drilled into the plate, one of which has an extra banking pin fitted into it.
I wish I knew the rest of the story. The owner contacted the person he bought the watch from; he wasn't aware of the extra holes and banking pin, so we will probabaly never know who, or why they were added. The extra banking pin does not come anywhere near any moving part underneath, and the two other holes don't do anything either. One of them is hidden beneath the balance cock, and neither can use used as an observation hole.

There was an image posted a while back on one of the boards of another one of these from the 4-millions. It had all of the hack mechanism parts. Does this example have the rest of the mechanism?

Jerry,
There are no other "extra" parts. If this was part of a hacking mechanism I cannot see how it might have worked, as the extra banking pin is nowhere near the gear train. The two "extra" holes are not tapped and do not appear to be factory quality work.

As I recall from the other example, a pin must come up through the hole under the balance cock to stop the balance wheel.

When in doubt, ask. The amount of expertise on this board is amazing! Jerry's comments look to have solved the "what was it for?" question. The pin and the holes were probably part of an addition of a hack mechanism that would stop the balance wheel at any desired time. This would allow the watch to be used as a somewhat crude chronograph mechanism for timing racing events, etc.

I believe the watch has Moses' patent hack mechanism US Patent Number 0414697.

This was a relatively easy one for the Patent Database at http://www.nawcc-info.org/PatentDB/PatentDate.asp

Hack mechanisms were mostly intended for synchronizing a watch to a time standard.

Here is a photo of the complete mechanism (courtesy of Bill Tapp).