Rocker rebuild

[<bilking@comcast.net>]

I am rebuilding the rocker arm assembly and have come across a problem.  When
I tighten the grub screw tight it binds the rear rocker arm.  Is it necessary
to fully tighten this screw or does the pressure of the springs keep it from
backing out?  I suspect the hole in the shaft to receive the grub screw is
drilled too far to the rear of the shaft so there is insufficient clearance
for the rocker arm.  A bit of wisdom from the group would be appreciated.

TIA
Bill