[TheForge] shrink fit techniques

[RW]

I'm having varying degrees of success attaching metal parts together by the
use of drilled holes filled with metal dowels using heat and a quench as the
"adhesive".  If I heat 1 1/2" solid and insert a cold 1/4 or 3/8" dowel and
quench, the result is a tight secure joint.  But when I insert this piece
(cold) into another  "hot hole" and quench, the second joint is not as tight
as the first joint .  I really like this approach for many applications and
would like to perfect the "shrink fit technique".  Any knowledge and
experience with this technique is most welcome and appreciated.
RW