We always recommend that employing the services of a good joiner to fit your new door. But if you wish to fit it yourself then we have compiled a few hints and tips for you.
Remove the old door. Try to keep the original door stop in the same place.
Allow for a 3mm gap between the hinged edge of the door and the lining. A butt hinge is ideal to measure this gap, this gap will allow for the ease of opening and closing the door.
If the door needs to be sized to fit the gap you must take equal amounts off both sides. You will generally look to be taking up to 6mm off each side.
You may want to mark a clear pencil line on both sides of the door to ensure that no more than what is required is taken off.
Lay the door down on its edge to plane the required amount off each side taking care not to plane past the pencil line.
You also need a 3mm gap at the top and bottom of the door. Bear in mind the finished level of the floor.
Mark with pencil lines as before and plane off the required amount from the edge. When using the plane you must work from the outer edge of the door inwards this will prevent splitting the end grain and possibly damaging the door. To remove more than a few millimetres, use a good quality hand saw.
When you are happy with the now planed door reposition the door into the door frame and mark across from the old position of the old hinges onto the outer lining of the new door.
Now lay the door down on its side again and draw a line around the edges of the hinge and mark on the front edge the hinge thickness.
Use a good sharp chisel to make two cuts at either end of the hinge position, allowing the chisel corner to cut slightly further than the line edge.
Taking care gently use the chisel blade to remove the wood by tapping the chisel along the pencil line at the front edge of the door, at the depth of the hinge.
When you have removed wood from all hinge positions, hold each hinge in place to ensure that the cut out will fit the hinge correctly. When you have the correct cut place the hinges into the cut and mark screw holes and pilot drill (2-3mm bit ideal). This will assist you in fixing the hinge to the door.
Then lift the door back into the door frame in an open position and fit the other half of the hinge into existing hinge positions on the door lining and screw in place. You might need someone to hold the door in place for you.
If you are fitting an internal latch mark top, bottom and end of latch case onto door face, line up with existing strike plate on door frame.
Then as you did with marking for the hinges, carry the pencil lines across the front of the door.
Measure the latch length and also the distance from the latch end to the spindle centre and mark on door.
Select a flat bit that is slightly larger than the latch casing, and to give you the correct depth mark the latch depth with tape or chalk this is a very good way to stop you drilling too far into your door. Hold the drill vertical to the door and drill slowly to the required depth.
At the marked off spindle position drill carefully into each door face taking care not to split the wood.
Push the latch into the hole and carefully position precisely vertical. Draw a pencil line around the latch plate. Then remove the latch and chisel to the required depth so that the latch plate sits precisely. Then drill pilot holes to take the screws.
Insert the spindle through the latch, please note long spindles may need cutting down with a junior hacksaw,and ensure that the spindle is firmly gripped in a vice or other suitable holding device, before you begin to saw.
Position the handles on the spindle. Make sure they are precisely vertical and use a suitable tool to mark fixing holes such as a gimlet or awl. Then you may screw the handles into place. (using a hand screw driver may be preferable rather than a powered driver has if the driver slips it may damage the door).
You can now check that the door and fittings have all been fitted correctly and make any minor adjustments that may be required.