wrote in message
ups.com...

Here's the rub. When the door has been hung and the shims are in, the
shims are roughly 24 inches apart on a three hinge door with shims
under each hinge. However, with MDF jambs, they will easily move and
torque even with shims 24" apart, and the trims properly nailed.

With longer screws that go into the door buck stud you can torque the
jamb if there is the slightest imperfection in your shim fit.

I hang my doors the old fashioned way, using long wedges from each side
at the hinges. Scribe and cut the wedges to fit after the door is in
its proper place, and more nails in the jamb, and a couple of 16 ga 2
1/2 " brads in each shim.

However, I discovered that when I countersink a large finish nail that
doesn't go exactly through the center of the wedge, I can literally
bend the MDF jamb around smaller shims (3" or so) when I am setting the
nails. Now THAT makes a nasty installation.

No Doubt.