[DesertRatTom]

I also did a search and found nothing but an overview of exterior parts. Craftsman gear is often a problem. I suggest you take a picture of the spring, and a straight down picture or two of the open router. Perhaps someone can figure it out. It would help to place the spring near a ruler so we can know a little more about it. Take it outside to take the picture.

 

[DesertRatTom]

Spring may have been behind a brush. Not sure what other needs for a spring a router would have unless there is a squeeze handle with lock button.

That's what I suspected as well. That kind of spring has wide gaps between loops, so a picture would have shown that. Heck, we're not sure if it is even a compression spring.