All About Doorknobs
There are two general types of doorknob
assemblies, mortise-mounted and bore-mounted.
Mortise-mounted hardware relies on a
large, rectangular metal box to hold its moving parts. Because of its size and shape, it
has to be installed into a hand-chiseled door cavity. This type of assembly is expensive
to buy and install.
At the turn of the century this was the
only type of door hardware available. And although mortise-mounted hardware is still
available, it is used most frequently on exterior main entry doors, sometimes in
restorations. Generally speaking, mortise-mounted hardware is still the finest that money
Because of its high cost, however, its
use on interior doors in modern homes has largely yielded to the easier to install and
less expensive bore-mounted hardware. Bore-mounted hardware costs less because drilling
two holes into the door, instead of chiseling, is used for installation. Installation is
quick and easy and comparatively inexpensive.
Doorknobs fall into the "you get
what you pay for" category. Less expensive doorknobs are made of inexpensive
materials and are susceptible to scratches and other kinds of wear and tear. The knobs (or
levers) are made of thinner and less expensive metals giving them a flimsy, tinny feel.
And if the knob includes a key-lock, the less expensive ones can be opened by most amateur
If the door hardware you're considering
is under very low price, chances are the finish will begin to wear off in two or three
years if not sooner.
There are two basic styles of
bore-mounted hardware: 1) exposed mounting screw type and, 2) the concealed mounting screw
You can tell which type you have by
looking at the escutcheon (trim ring) between the knob and the door. If you can see screw
heads in one of the trim rings, you have the exposed mounting screw type. If screws are
not visible, then you have the concealed mounting screw type.
In our opinion concealed-screw hardware
is better than the exposed-screw style not only because it's better looking, but because
more pressure can be applied to the concealed mounting plates that hold the doorknob in
place. With exposed screw hardware, when screw pressure is applied to the trim plate to
hold it in place, there is a chance of bending it. Leaving the screws loose enough to
prevent damage to the trim plate can result in the frequent need to retighten the hardware
a nuisance at best.
For less maintenance and a cleaner
appearance, concealed screw doorknob assemblies are superior.
The Locking method also is an important
consideration. There are two basic choices: 1) Manual relock key opens latch and changes
hardware to unlock position, and 2) Auto relock key opens latch but hardware remains in
The first type must be relocked with a
key or the twist of a lever each time it is unlocked with a key.
If you want a door to remain locked at
all times even after you have used a key to make entry, then you want the second type.
This is most frequently seen on the main entry door. With this kind of hardware the unlock
mode is accomplished by a release lever or button. The key allows passage but does not
control the lock-unlock function.
The auto-relock function is most common
in mortise-mounted hardware, but is also available in the bore-mounted type.
A nice thing about bore-mounted hardware
is most manufacturers use a universal bore. The bolt hole is usually one inch in diameter
and the knob hole usually two-and-an-eighth inches in diameter. If you have one brand and
want another, the bore required by both is the same.
For a new door, you'll need a one-inch
drill bit, a two-and-an-eighth-inch holesaw, a chisel to recess the bolt plate and strike
plate and a screwdriver to install the parts. Installing bore-mounted hardware in a new
door isn't difficult and nothing could be more simple than retrofitting old with new.
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