To add to what ger21 just posted, the router body position on the mounting brackets is most important when you need the full travel possible, and the longest bit length available, just to reach down into cavities of some object you are routing. Deep moulds for fiberglass lay-ups and castings come to mind. The router body position on the mount can cause chatter with long bit lengths if the router body is extended so far below the mounts that it is not well supported by the mounts. For most work I would keep the bottom of the router body at the lowest router mounting bracket and choose the shortest bit length needed to reach into the lowest parts of the cavity, Use the minimum z axis travel needed to do the cutting. Cutting bit chatter can make a mess of precision mold making, and craft projects.
CarveOne
CarveOne
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