What am I looking at?

[bonusbuilt1950]

I've got a Waltham Riverside movement, #4869178, 16s that has a stud sticking out the side. I went to put it in an open face case and it will go in except where that stud is. Just won't sit flat. it's not a dial face retaining screw. I looked at it thru a Loupe and it is just a stud sticking out of the case. I'm posting a pic of it. No idea why it's there or what it's purpose is. Any ideas?

 

[roughbarked]

Are there other things of interest, like where does the winding stem line up?
At the 12 or the 3?

 

[Dave Coatsworth]

The model '88 uses a single case screw. Most movements that use a single case screw have a pin opposite that will go into a hole in the case rim. You are looking at just such a pin.

 

[Jerry Treiman]

In addition to what Dave said, these 1888 model movements are a little larger than 16 size and will not fit a standard 16 size case

 

[bonusbuilt1950]

So I need to find a case especially for a model 1888? Do I look for one by measurement in MM? Learn something new every day!

 

[roughbarked]

Yes. Measurements would help you a lot. The pin has to fit under a rim and be tightened by the one screw on the other side.

 

[bonusbuilt1950]

I did some checking on Ebay to look at other Riverside movements and found a couple with those pins, but not in the same location. Mine is at the 5 O'clock position. I saw 2 that were at the 3 and 7 O'clock positions. Most did not have the pin. From what I saw, the year made a difference.

 

[Dave Coatsworth]

Often they are missing. Pretty much any movement that only has one case screw should have a pin. Otherwise the movement will not be secure in the case.