Tom; can you post a photo?
Normally of course the jamb nut would tighten against the component that's at risk of loosening/moving. Are you saying that the armature or shaft has an adjustment as well?
(Sorry, I can't picture what you're describing. )
Welcome to the forum, sorry to hear you are having trouble with your router. I can not visulize your problem, Save a picture to your desktop, then drag it into the space at the bottom that says "Drag and Drop file"
Most routers have a nut on the shaft that you can hold the shaft, with a wrench from turning while you loosen/tighten the collet nut.
If you mean the nut that holds the collet in the end of the router shaft to lock the bit in place, most routers today have collets with a groove around the outside that the collet nut is supposed to snap into and make an assembly. Then, when loosening the collet nut you need to loosen it about one turn further and this will pull the collet out of the router shaft, loosening the bit for easy removal and change. If you don't snap the collet into the nut before use, you cmay have considerable difficulty removing the bit after use, since the outside of the collet is tapered and will nest tightly into the tapered hole in the inside of the router shaft. Getting the router bit out after use is much easier with the collet and nut snapped together before use, so the nut will hold the collet and bit tightly in use, but also help to pull the collet out of the router shaft when removal / changing of the router bit is desired.
I have no experience with your model router, but most routers made since about 1960 work this way.
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