On Fri, 07 Nov 2014 19:18:02 +0000, Big Fred wrote:

[re eg http://www.harborfreight.com/two-speed-variable-bench-mill-drill-machine-44991.html]
I have a HF Mini-Mill #44991 that needs to have the drill chuck removed
from the spindle in order to install a taper shank cutter. After removing
the spindle cover, I inserted the Fixing Pin into the spindle sleeve and
loosened the Spindle draw bar. The instructions say that all I have to
do is gently tap the taper shank (hidden by the drill chuck?) and let the
drill chuck fall out. As you would guess, the drill chuck is stubborn and
no matter where I hit the drill chuck it remains fixed in the spindle. I
am using a hard rubber mallet. This machine is new and was shipped with
the drill chuck already installed on the spindle.
....

Don't hit the drill chuck or the taper shank (which is an R8 taper).
Instead, after you loosen the drawbar half-a-dozen turns (such that it
still has numerous threads engaging the the R8 shank of the drill chuck,
and still has the 19mm nut on top) tap or rap the top of the drawbar.
One sharp tap should loosen it, and having the drawbar still engaged
keeps it from moving more than about 1/8" in this initial loosening
step. After it's loose you shouldn't need to tap it any more. (But
if the keyway in the R8 shank wasn't aligned with the alignment pin
inside the spindle, but incorrectly forced into place, it might not
come loose that easily.) Note, place a 6" cutoff of 2"x6" lumber on
the table below the spindle when changing collets or chucks.

Engage the crown nut and lock the clamp below the head to keep the
head from moving when you tap on the drawbar.

--
jiw