My Bosch 1617 plunge router drops 1/16″ after a minute of use. It doesn’t matter what bit I use (1/4″ or 1/2″ collet, dovetail, dado, spiral up cut…). I thought it might have been debris in the collet so I lightly touched it up with Emory cloth on the inside.  I cleaned all the router bit stems with wet dry sand paper. I cranked the bit down extremely tight just to be sure.  Bits are inserted all the way in and backed out a little to give room for heat expansion of the stem.  I tightened the router body clamp tight when attaching to the plung base. Yet, it drops 1/16″ each time. I am totally stumped. Anyone seen this before?