Historic Preservation - Technical Procedures
- Resetting A Hinge Mortise
- Procedure code:
- Hspg Prepared For Nps - Sero
- Doors And Windows
- Door Hardware
- Last Modified:
- Resetting A Hinge Mortise
- Last Modified:
Resetting A Hinge Mortise
Procedure code: 0871201R
A. This procedure includes guidance on shimming a hinge mortise to bring it flush with the surface of the door or frame.
B. If the door has a springy resistance to closure, the cause may be paint buildup or a poorly executed repair. If too much material was removed when hinge mortise was being cut or repaired, the hinge may have worked itself loose.
C. For guidance on re-securing loose hinges which are causing the door to bind, see 0821001R.
D. See 0110007S for general project guidelines to be reviewed along with this procedure. These guidelines cover the following sections:
1. Safety Precautions
2. Historic Structures Precautions
4. Quality Assurance
5. Delivery, Storage and Handling
6. Project/Site Conditions
7. Sequencing and Scheduling
8. General Protection (Surface and Surrounding)
These guidelines should be reviewed before performing this procedure and should be followed, when applicable, along with recommendations from the Regional Historic Preservation Officer (RHPO).
A. Scrap wood for shims; or prefabricated plastic or metal shims.
B. Utility knife or hack saw to cut shims
A. To discern the door problem, observe the door open and close a few times. Note the location of any binding or rubbing. Note also if doors bind inconsistently from top to bottom or hinge side to latch side.
3.02 ERECTION, INSTALLATION, APPLICATION
A. If problem is paint buildup, paint will need to be stripped from the surface of the hinges and involved surfaces of the door and frame.
1. To remove paint from a wooden door and frame without removing the hinges, sand the area around hinges by hand using sanding blocks or sponges; repaint.
2. To removal of paint from metal hinges is best done after complete removal (see 3.02 B. a-f) because doing so in-place can cause inadvertent damage to the surrounding materials.
If only a small amount of paint is to be removed from the surface, mask off the area around the hinge with painters tape, then carefully sand or scrape the paint, taking care not to damage the frame or door. Use tarps under the door to collect debris, utilize proper PPE for exposure to hazards contained in the dust being created, and clean up thoroughly.
The use of chemical stripping agents while a door is in place in a finished environment should be avoided, as complete neutralization and removal of the chemical is nearly impossible outside of the workshop.
B. If problem is more serious, remove door and hinges from jamb using the procedures below.
1. Close door and place a wedge under the door to take weight off hinges.
2. Remove the bottom hinge first, then the next, finishing with the top one (the top supports most of the weight). Tap pins gently up and out with hammer and screwdriver (be aware that all hinge pins are not meant to be removed). Apply penetrating oil if pins resist.
3. If a pin still resists, grasp finial of hinge pin gently and carefully twist with pliers to break the bond. Try tapping pin out again.
4. If the pin still resists, remove bottom finial and force pin out from bottom with punch and hammer.
5. Unscrew hinge from the jamb. Note: A second person must support door during hinge removal. Remove paint from hinges using the following procedure:
a. Place the hinges (or other metal or porcelain hardware) in a large metal cooking pot with a solution of 4 quarts of water and 4 tablespoons of baking soda.
b. Place on a kitchen stove over a low-to-medium heat to simmer (not boil) for 30 minutes.
c. Remove the pieces while still hot, using tongs. Place on paper towels, then carefully brush with a stiff nylon bristle brush to remove all paint. Dispose of debris using proper waste procedures.
d. If some paint will not come off, place back in the pot for another 30 minutes and try again.
e. If there is no rush, the hardware may instead be placed overnight in a residential-grade ���������crock-pot��������� slow-cooker, and they will be ready for cleanup the next morning.
f. Be aware that the cooking pots utilized for this operation should never again be used for food or other consumables.
C. Cut scrap of thin wood or use a prefabricated metal or plastic shim the exact dimensions of the recessed mortise so that hinge will be flush with jamb.
D. Put the shim in place and replace hinges and door.
END OF SECTION