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All You Need to Know About Hinges

Topics Covered In This Article:

Determine the Type of Hinge

Standard Hinge Types:

Full Mortised Full Surface Half Mortised Half Surface
Full Mortise Hinge Full Surface Half Mortise Hinge Half Surface Hinge

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Selecting the Proper Weight and Bearing Structure

Due to the variety of door sizes and weights, hinges are placed into three groups:

  • Heavy Weight, Ball Bearing (5-knuckle) or Anti-Friction Bearing (3-knuckle): For use on heavy doors of high frequency usage.
  • Standard Weight, Ball Bearing: For use on medium weight doors of medium frequency usage.
  • Standard Weight, Plain Bearing: For use on light weight doors of low frequency usage.
  • Residential, Plain Bearing: Hinge leaves are thinner than commercial with Plain Bearings.

It is advisable to include in your calculations of door weight, the approximate weight of additional hardware (door closers, exit devices etc.) that will be installed on the door.

Bearing Structures:

  • Plain Bearing-The hinges do not have any special bearing structure. They are standard hinges for use on light weight doors in low traffic environments.
  • Anti-Friction Bearing (AB)-These are made of concealed resilient engineering plastics that provide a self-lubricant and very strong bearing surface. The nylon acts as a cushion for the door, yet allows the door to flow smoothly on the surface of the nylon with an extremely low wear factor. 
  • Ball Bearings (BB)-Ball bearings are engineered to throw the knuckle weight against specially hardened steel raceways, which ride on the bearing surfaces. The one-piece cup protects the bearings from moisture and dust. Standard Weight Ball Bearing Hinges contain 2 ball bearings for extra durability. Heavy Weight Ball Bearing Hinges feature 4 ball bearing for additional smoothness.
Plain Bearing Concealed Anti-Friction Bearing 2 Ball Bearings 4 Ball Bearings
Full Mortise Plain Bearing Hinge Concealed Anti Friction Bearing Hinge 2 Ball Bearing Hinge 4 Ball Bearing Extra Heavy Weight Hinge

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Determine the Size of the Hinge

Hinges have 2 dimensions. The first indicates the height and the second indicates the width of the hinge in the open position.

Height of Hinge:

Door Thickness Door Width Height of Hinge
1-3/8" To 32" 3-1/2"
1-3/8"  32"-36" 4"
1-3/4" To 36" 4-1/2"
1-3/4" 36"-48" 5"
1-3/4" Over 48" 6"
2", 2-1/4", 2-1/2" To 42" 5" (Commercial) 
2", 2-1/4", 2-1/2" Over 42" 6" (Commercial)

Width of Hinge: 

Important Note: the width of the hinge always refers to the full leaf span - meaning in the open position.

This chart is for basic dimensions. For more complicated dimensions, see below the chart for the formula.

Door Thickness Standard Backset Max Clearance Provided Width of Hinge
1-3/8" 1/4"  1-1/4" 3-1/2"
1-3/4" 4"
1-3/4"  1/4" 1" 4"
1-1/2" 4-1/2"
2" 5"
3" 6"
2" 1/4" 1" 4-1/2"
1-1/2" 5"
2-1/2" 6"
2-1/4" 1/4" 1" 5"
2" 6"
2-1/2" 3/8" 3/4" 5"
1-3/4" 6"

3 dimensions to know to determine the minimum width of a hinge: Door thickness, backset and clearance required.

* When figuring calculations for a: 

  • wood door and wood frame, the door is flush with the casing or face of the frame.
  • wood/metal door and hollow metal frame, door is inset approximately 1/8". 

* For doors up to 2-1/4" thick, the hinge is set back 1/4" from the back face of the door.

* For doors over to 2-1/4" thick, the hinge is set back 3/8" from the back face of the door.

Once these dimensions are known, the formula can then be applied:

(Door thickness - backset) x 2 + clearance required = Hinge Width

If the hinge is not standard, go to next larger hinge width. If the width of the hinge is greater than the height it is a wide throw hinge (only on full mortise hinges).

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Determine the Number of Hinges Required

Referring to Door Height:

As a general rule you will want to use one hinge per every 30" of door or fraction thereof.

  • Doors up to 60" need two hinges.
  • Doors 60"-90" need three hinges.
  • Doors 90"-120" need four hinges.

Referring to Door Width:

Door with a width greater than 37" and up to 48", an extra hinge can be used for additional strength.The extra hinge helps support the additional weight and tension applied to the frame created by the wider door width.

Spring Hinges: Always apply at least two spring hinges.

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Hinge Location

Upper Hinge - 5" from top jamb to top edge of barrel.

Bottom Hinge - 10" from bottom edge of barrel to finished floor.

Middle Hinge - centered between top and bottom hinges.

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How to Determine Corner Radius

Measure the beginning of the curve to where the corner of the hinge would be if it were square.

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Choosing Hinge Base Material

  • Steel: This has the greatest strength, but is is a corrosive material. Steel will rust in unstable environments. The best application for steel hinges is a controlled environment such as inside a building where the temperature and humidity are controlled.
    *Can be used on fire rated or labeled door openings.
  • Stainless Steel: Also has great strength and in addition it is rust resistant. Another advantage is that it can be polished to a satin or bright finish.
    *Can be used on fire rated or labeled door openings.
  • Brass: Non-corrosive, rust resistant and very decorative. However, it has less strength than steel and stainless steel.
    *Cannot be used on fire rated or labeled door openings because of its low melting point.

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Choosing the Number of Knuckles

There are 2, 3 and 5 knuckle hinges in the Door Hardware industry. 

What are the differences?

2-knuckle hinges are used mainly in residential environments, although Hager Companies does offer 2-knuckle architectural hinges. The only difference between Hager's 2 and 3-knuckle hinges are appearance.

3-knuckle hinges have a cleaner look than 5-knuckle hinges and have different types of bearings:

  • 3-knuckle hinges can be either plain bearing or anti-friction bearing.
  • 5-knuckle hinges can be either plain bearing or ball bearing.

Basically it is a matter of preference.

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More Hinge Types

Swing Clear Hinges

This is used when the passage area must be the full width of the opening. Swing clear hinges are designed to swing the door completely clear of the opening when the door is opened 95°. The door opening will be clear of the hinge and the door edge so that large objects passing through will not cause any damage to the door. This hinge type is ideal for use in buildings such as hospitals where stretchers and gurneys must pass through the door ways.

Anchor Hinges

Anchor hinges are intended for use on heavy wood or hollow metal doors in high frequency applications such as hospitals, schools and public use buildings. These hinges are specially designed for use on doors where additional door hardware, such as door closers and holders, may cause excessive strain or abuse to the door, frame and/or hinges.

Anchor Plates may be attached to either the frame and/or door. Their screws are placed in shear, this prevents the hinges from pulling loose on the door or the frame.

Two variations:

  1. Single Extension Leaf-extension leaf is mortised into the frame only.
  2. Double Extension Leaf-one leaf is mortised into the frame and the other leaf is mortised into the top edge of the door. It will be necessary to know if the doors are square edged or beveled edge.

Spring Hinges

Spring hinges are fitted with one or more springs to close a door automatically. For maximum versatility use all spring hinges or spring hinges with ball bearing hinges. Do not use together with plain bearing hinges.

Two Variations:

  1. Single Acting-contains one barrel with the spring inside.
  2. Double Acting-contains two barrels with springs inside. The hinge opens and closes fully in both directions-great for a door in a commercial kitchen.

Detention Hinges

Investment cast full mortise hinges (HIHTHB953 Series) are the standard 4-1/2" x 4-1/2" size with a mortise depth of 0.187". These hinges can carry door weighing up to 600 lbs.

Swing Clear Hinges Anchor Hinge Spring Hinge Detention Hinge

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Determine Door Handing

See our How to Determine Door Handing / Swing

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