Fitting a Door Blank
If you are putting a new door blank into a existing jamb, consider installing the door knob first. It can help you control the door while test fitting and handling.
Set blank into the opening and block it up off the floor and shim it on the strike side and the bottom. You’re aiming for an even 1/16" gap at top, an even 1/8" gap on the strike side and up to a 1/4" gap on the bottom. (If installing carpet later, include that in bottom clearance.)
A new door blank will probably need to be planed to fit an older opening.
If you’re fitting a new door in an existing opening, carefully transfer the location of the existing hinges onto the new door. Mortise out the door for the hinges and install the separate leaves on the jamb and the door.
If you’re installing hinges from scratch, we usually locate one 7" from the top of the upper hinge to the top of the door, one 11" from the bottom of the lower hinge to the bottom of the door and one hinge dead center. Locate the hinges to stick out slightly from the jamb so they won't "pinch" when opening or closing.
TIP: Don't completely tighten the screws to allow the hinges some "play" while getting the hinge pins in.
Set the door into the opening, tap the door pins in and test the door.
Adjusting a Door
Even a carefully hung door may bind or sag a bit. Also, accidentally making the hinge mortise too deep creates an uneven gap along the latch side of the door.
Both of these problems may easily be corrected by shimming a hinge or two with a cut piece of cardboard, thin flooring scrap, or in some cases a shim cut out to fit behind of the hinge.
Close the door and check the gaps. If the door binds at the top hinge, shim the top hinge and snug the bottom hinge, and vise versa for a door binding at the bottom hinge.
If the door sticks at the top strike-side corner, tighten the top hinge and shim the bottom hinge, and vise versa for a door sticking at the bottom strike-side corner.
Door Knob Tips
Do not try to install a door knob without an appropriately-sized hole saw. Go buy one—and a good quality chisel for mortising.
Most knobs and latch kits have instructions and a handy template to use, so we won't discuss actual installation here. In most cases, the knob and latch are located 3' from the bottom of the door.
With the knob on, locate the strike plate location by transposing the knob location measurements. A less conventional method is to "color" the knob latch point with pencil lead, turn the knob to retract the latch, position the door shut, and release the knob to mark the edge of the strike plate on the side jamb.