In rec.woodworking
wrote:

The router base plate that i got with my "universal" table has many
holes in it for different tools, ie router, jig saw etc. These many
holes are useless to me and always seem to be catching the corner of
wood that i am trying to rout. I have gotten a couple of steel plates
pieces that are thick enough and big enough that I am going to make a
new router plate. My question is how do i make the holes (4 ea ) in
the plate so that they are inset to hold a beveled head of a bolt and
below the level of the plate. The plate is not thick enough to drill
the hole then bevel it out. I know i could buy a plate that is made to
do this job but these plates came along and will be much better than
the one that is one there.
1. Do I drill the holes big enough for the screw shaft then using the
bolt, hammer it in place so that it creates the correct bevel?
2. Do i try to hammer in the bevel before making the screw hole?

You countersink it just like you would do with wood. If it isn't thick
enough to do that, it isn't thick enough period. How the hell would it
hold otherwise?