Mercer crank
It definitely sounds like the gears are stripped out, but I don't know what to recommend to replace your whole assembly. This is a very old part and you probably aren't going to find an exact match anywhere. can you show me a picture of your complete operator mechanism out of the window? Seeing the whole thing in one shot will allow me to see if anything in our inventory matches. Dimensions would also be a big help, if you can get them.
Assembly looks to be 5" long and the slot in the frame is 3". Frame height is 3/4"
I don't need you to disassembly the operator, I just need to see it out of the window and a photo of the whole thing in one picture.
I recommend looking through our selection of operators here. You may be able to find a match, but at the very least you'll get a good idea of what kind of photo I need.
The 39-001 does look similar, and if the dimensions are the same then it very well may be our best option. I'm not sure if the tapering arm is really necessary for it to function, but these windows are so old that I can't really make any promises.
