Router plate system Bosch 1617 (RA1165 Base)

This is a plate for table mounting a Bosch 1617/1618 with the table mount base (RA1165).  It is designed to flush mount in ¾" plywood (actual height .72" / 23/32").  I had a ¾ MDF below that to support the plate, but this could be anything thick enough to hold the router.  I have been using this reliably for a few years printed in PLA (not solid but with extra perimeters)

The insert has a custom 3 start thread that allows it to thread into the router plate and sit flush with the plate, quicker than using multiple mounting screws.  With the insert removed you can access the collet using the standard tools to change bits, and there is hole for the depth adjustment from above.   So you don't need to remove the router to change tools or depths, and you only need to access the bottom to change speeds, or make the large step changes in height with the clamp.

The square hole (6 5/8") in the top surface can just be cut out using jigsaw and 5/16" holes for the corner. I recommend rough cutting the octagon shape and using the template to route out the final shape and drill the holes (sized for ¼" threaded inserts) in the proper location.  spanner tool needs 5/16" dowels, use wood, plastic or print some.  The router base mounts to the plate with 4xM4 counter sunk screws.

This could easily be modified for a larger hole within slicer.  You could make minor vertical scale changes to account for your actual top surface thickness as long as it is still ~¾" nominal.