Thread: What's this part of the router plate for?

It's a starter or freehand pin when using bearing tipped bits freehand without a fence to help guide your work piece onto the bit with more accuracy.

Well there you go! Thanks very much for that.

If you try to hand feed without a fence or pin, the router bit can grab the workpiece and throw it, possibly drawing your hand into the bit and causing grief. If you are say profiling straight material, you use the fence to control the materials exposure to the bit. If your workpiece is not straight, you move the fence well clear of the bit, install the starting pin, and position your work between the bit and yourself, bit in contact with the pin. With the pin between both hands and the bit, you can safely rotate the work around the pin to make contact with the bit and start the cut. Once the cut is established (work is riding against the bearing), the bearing limits the depth of cut and it becomes safe to move the work clear of the pin and hand feed it, provided you keep your hands well clear of the bit. If you interrupt the cut for any reason, you need to use the pin to restart.