Just going through the tutorials and starting to do some of my own simple sketches.  I have created a simple assemby of a lower plate with a hole in it.  I then created a created/insert/new part.  I designed a guide pin to go into the hole.  When I try to mate the pin into the hole (mating the bottom surface of the pin to the bottom surface of the plate) it goes into for only a second and then snaps up to the top surface of the plate.  For the life of my I can't figure out why the pin wont go into the bottom of the home.  Thanks so much for the help.

Mike