One of the classic tests that distinguish a skilled carpenter
from a wannabe is the ability to hang a door the old-fashioned
way: assemble a jamb set, fit the door blank, mortise the
hinges, and put all the pieces together.
Hanging a door from scratch is way more time-consuming than
installing a prehung, but it's an extremely flexible process.
If I need to hang a door in a hurry and can't wait for the
lumberyard to order a particular prehung, it's a safe bet that
the jamb material and door blank I need are in stock.
More often, if I'm remodeling an older home and need to fit a
door to a nonstandard rough opening — or if I want to
recycle a salvaged door panel — the solution is to build
a custom-sized jamb set and trim the door to fit.
Assembling a Jamb Set
Years ago, before prehung doors became as popular as they are
now, you could buy ready-to-assemble jamb packages for popular
door sizes that simply needed to be nailed together. These
days, the suppliers in my area keep only 7-foot lengths in
stock, so even a standard door frame has to be cut to
If I'm fitting the jamb to an existing door blank, I measure
the door and add 3/16 inch to the width and about 1/2 inch to
the height. These measurements represent the inside dimensions
of the jamb.
For strength — as well as appearance — I rabbet the
tops of the side jambs to receive the head jamb (see Figure 1).
It's possible to use a trim saw and a chisel to plow out the
rabbets, but a router does the job faster and better.
Figure 1. A square-cut scrap of jamb stock
(A) acts as a straightedge for routing a 1/4-inch-deep rabbet
into the top end of each side jamb (B). Carpenter's glue (C)
and 2-inch screws (D) ensure that the jambs stick together for
the long haul. To prevent splitting the narrow jamb material,
all of the screws are countersunk.
Before cutting the head to length, remember to add 1/2 inch to
account for the 1/4-inch depth of each rabbet.
Routing the rabbet. After scribing
the thickness of the head jamb on the end of each side jamb, I
make another pencil mark that represents the width of the
router's base plate (measured from the inside edge of the bit)
and clamp a straightedge at that point.
I make a test cut on a piece of scrap to verify that my
measurements are accurate and that the router's depth setting
is spot-on, then I rabbet all of the side jambs one after
I fasten the parts together with carpenter's glue and 2-inch
If the door stops are on the job at this time, I'll tack them
in place using a method shown on the last page of this
Setting the Jambs
A solid-core door panel can weigh 100 pounds or more. To
support this much weight, the jambs have to be securely
fastened — but they must also rest solidly on the floor.
Otherwise, over time, gravity and centrifugal force will take
I always check the floor with a level to determine whether one
side of the rough opening is higher than the other (Figure 2).
If the jambs will rest directly on a subfloor, I simply place a
shim underneath the low side. If the jambs are set directly on
top of a finished floor, as they were on the job shown in the
photos, I scribe the high-side jamb and cut it to fit.
Figure 2. Before putting in the door
jamb, the author checks the floor with a level to determine
whether one side is higher than the other (A). Since this jamb
is resting on top of finished flooring, the high side must be
scribed (B) and trimmed, or the head jamb won't sit level. A
fine-toothed Japanese pull saw is more accurate than a power
saw and cuts almost as quickly (C).
I roughly center the jamb in the opening, using a homemade
spreader to keep the width at the bottom the same as at the top
(Figure 3). I then slip a pair of shims behind the bottom hinge
and pin the jamb by driving a pair of 2 1/2-inch nails
Figure 3. After the jamb is placed inside
the rough opening, a spreader keeps the bottom square with the
top, while a straightedge ensures that the assembly stays in
plane with the wall (A). With the jamb centered in the rough
opening, the bottom hinge is shimmed and tacked, with nails
driven beneath the shims to permit adjustment (B). Then the top
hinge gets the same treatment (C). Note that although the
author is using a prehung door jamb in this photo sequence,
installation of a site-assembled jamb set is exactly the
I plumb the face of the jamb with a 6-foot level, then shim and
pin the top hinge following the same procedure. I don't secure
the latch-side jamb until after the door is completely
Test Fitting the Door Blank
In the bad old days, a door blank was truly a "blank." Cut
square on all four sides, it had to be trimmed — and the
latch side beveled — on site to fit the opening. Still
available, but often only by special order, this type of door
is called "full and square."
These days, "prefit" door blanks are more common; they're
beveled on both sides and slightly undersized, so a 3/0 door
blank should fit perfectly inside a 3-foot jamb opening.
Before making any cuts, I like to prop each door blank inside
the designated jamb, shim it tight against the head, and check
the fit on all sides. If the jamb was installed without stops,
I tack a short length of scrap to the head jamb to prevent the
door from falling backward.
It's particularly important to make sure that the latch-side
edge of the door is beveled, and that the bevel faces inward.
To prevent a costly mistake, I put a mark on the top corner of
the door that reminds me where the hinges will go (Figure
Figure 4. The author marks the top corner
of the door (A) to designate both the hinge side and the edge
that should get fully mortised. Before taking the door down for
mortising, he scribes the bottom to fit the floor (B). Although
they're expensive, specialized cutting tools like Festool's
plunge-cut saw (C) and Porter-Cable's 9118 planer (D) make
trimming and beveling edges error- and splinter-free. A simple
door buck, assembled from scrap 2x4s, holds the door
On those occasions when I'm installing a "full and square"
door, I hold the latch side jamb tight against it; then I open
my scribers to 3/16 inch and scribe the door. I keep an older
Porter-Cable 9118 planer permanently — well, almost
permanently — set on a 3-degree bevel, and I always work
from the same side of the door, so it's a simple matter to put
the right bevel in the right place.
Before I take the door out of the opening, I set my scribers to
the proper width and mark the cut for the bottom of the door.
In most cases, I like to see a 1/2-inch gap between the bottom
of a door and the finish floor; I usually leave 1 inch of space
beneath bathroom doors to allow for ventilation.
For years I cut door bottoms the tedious, old-fashioned way,
using a straightedge to guide a standard circular saw. Last
winter I started using the Festool plunge-cut saw and
guide-rail system. With this tool there's no need to measure
for an offset — or to knife-cut the grain to prevent
splintering. Instead, you just clamp the base on the cut line
and the rest is gravy.
Like all Festool products, the saw is hideously expensive, but
it's well worth the cost if you hang a lot of doors or need a
first-rate dust-collection system.
If I'm hanging just one door, I mortise the hinges freehand
with a laminate trimmer and a chisel; for more than one door, I
use a full-size hinge template (Figure 5).
Figure 5. Before setting the pins that
fasten a hinge mortising template, the author makes sure that
the stops underneath and at the top fit tightly against the
door (A). To work with a template, he fits the router with a
1/2-inch mortising bit encircled by a 5/8-inch template guide
(B). This setup leaves rounded corners that are easily squared
up with a soft tap on a corner chisel (C). A self-centering Vix
bit ensures that the hinge screws lay flat (D).
Manufactured hinge templates come in a variety of styles. Fixed
units, such as those from Templaco (800/578-9677,
www.templaco.com), are inexpensive and easy
to set up, but you need a different one for each size hinge,
and they take up valuable storage space.
I use a Bosch adjustable hinge template (877/267-2499,
www.boschtools.com). It's a bit of a pain
to set up but extremely versatile — and when I'm done,
the whole contraption fits into a case that's not much bigger
than a lunchbox.
After assembling the template and setting up the router, I
practice on a 2x4 to make sure that the location of the hinges
and depth-of-cut are correct. I secure the panel on its edge in
a door buck, then fasten the template to the door using the
To prevent chipping, I rout the top and bottom edges of the
hinge mortise first; then I plow back and forth across the
grain before making a final pass around the perimeter of the
template to make sure the edges are crisp and smooth.
After the template is removed, a corner chisel makes quick work
of the radius corners left behind by the router bit. I check
the fit of each hinge, then use a self-centering Vix bit to
drill for the screws. To allow wiggle room when hanging the
door, I put only two screws in each hinge at this time and
leave the screws loose.
The jamb gets mortised in place, following the same procedure
as for the door (Figure 6). Then I separate the hinges, fasten
the loose hinge leaves to the jamb, and go back for the
Figure 6. To cut the hinge mortises for
the jamb, the author butts the template's end stop gauge tight
to the head jamb, then makes sure before he sets the pins that
the two thickness stops on either side of each hinge section
are tight to the frame (left). He follows the same procedure
for cutting the mortises as for cutting the door
Hanging the Door
I set the door panel in front of the opening and lever the
hinges into position (Figure 7) using a foot-operated board
lifter that I bought from a drywall supplier
(www.marshalltown.com ). After the hinge
pins are in place, I tighten the screws.
Figure 7. Although it's designed for
drywall, a board lifter is an ideal tool for finessing a
solid-core door onto its hinges. Unlike a pry bar, this tool
has a built-in fulcrum as well as a stirrup, so you never need
a third hand to reach down and reposition it.
Now I'm ready to fasten the latch side jamb. With the door
closed, I shim the jamb at the top and the bottom, making sure
that the reveal is the same on the side as it is on the top of
Then I open the door and pin the jamb by driving a pair of
nails underneath each set of shims. I use a combination square
as a straightedge to align the jambs with the drywall.
When I'm satisfied that the reveal is consistent and —
most important — that the door swings freely, I nail
through the shims to make sure they can't slip loose. The jamb
also gets shimmed and nailed behind the latch.
If I didn't tack on the stops when I assembled the jambs, I
usually hold off until I'm set up to run casing and
To lay out the stops, I mark a point on the face of the jamb
that corresponds with the inner edge of the door, then scribe a
line with a combination square (Figure 8). To prevent the door
from binding (especially after it's been repainted a few
times), I leave the pencil line showing everywhere except for
the point where the strike plate will be located —
usually 3 feet above the floor.
Figure 8. When it's time for door stops,
the author scribes a pencil line the same thickness as the door
on the face of the jamb (left). To prevent the door from
binding, he leaves the line showing, except for at the point
where the strike plate will go (right).
Until the lockset goes in, I pin the stops with just three or
four brads each. Once I'm satisfied with the operation of the
door — when I hear that subtle, reassuring thunk as it
shuts smoothly, with no bounceback — I'll nail the stops
home.Formerly a carpenter in New Milford, Conn., Tom
O'Brien is now an associate editor at JLC.