I occasionally need to place a mate as shown below.  I want the edge of the washer to be touching the gray plate.  It seems as though I should be able to place a tangent mate between the edge of the washer and the face of the plate, but that doesn't work.  The only way I have been able to do it is with a distance mate between the washer or nut and the end of the shaft, then just play with the distance until it looks right.  That takes a while and it seems like there should be a better way.  Anybody have any ideas?