Step one: attack your door
Making the first cut or drilling the first hole in your door can be a bit nerve racking, so there are a few things you need to keep in mind. You will be pleased to know that you can be a bit rough with your cuts, because the door knob will cover the rough edges.
The first thing you should do is work out where the door knob will be positioned on the door. The position depends on two variables. Firstly, how high off the ground do you want your door knob to be? If there is already a recess for the latch on your door frame then this will determine the vertical position of your door knob.
The second variable is how long the latch mechanism is. Most door knobs come with a spring attached and a square rod that passes through the latch mechanism and connects the knobs on both sides of the door.
Hold up the latch against the door, and measure where the hole for the rod attached to the centre of the door knob will pass through. Then allow up to 5mm for the fact that your latch will be recessed into the end of the door. Mark this point as the center of your door knob.
Cutting the hole for the mechanism
Draw a circle on you door that is the same diameter as the base of the door knob. This gives you an area to work within because anywhere inside this line will not be visible when the door knob is installed.
Now work out how big you hole needs to be to accommodate the spring and any other parts that will pass through the door and draw the outline of your cut.
The best way to cut the hole is with a drill and a jigsaw. Drill holes around the outline of the cut then finish the cut with your jigsaw (or hand saw if you don''t have a jigsaw). Check the door knob fits the hole and widen if necessary. But stay inside the diameter of the door knob base or your cut will be visible after the door knob is installed.
Cutting the hole for the latch and mechanism
There are two steps to this part of the process. First you need to bore a hole to hold the latch mechanism. Secondly you need to chisel a recess for the latch so it sits below the level of the door frame and won''t prevent the door from closing properly.
The best way to bore the hole for the mechanism is to drill a small pilot hole and then use a boring drill attachment. After drilling the main hole you may need to widen it with a hand saw or chisel until the mechanism fits (see picture at right). Remember you can be rough with these cuts as they are not visible when the latch is installed.
Now outline where the latch and the latch plate will sit on the edge of the door. Hold your chisel at right angles and imprint the outline. Now you should be able to cleanly chisel out a 3-5mm recess for the latch.
Putting it all together
Slide the latch and mechanism into the hole you created, if it fits properly and lines up with the other hole you created for the door knob then use screws to secure it to the door.
Now hold both door knobs on each side of the door and slide the mechanism into the cavity, making sure the rod passes through the latch mechanism.
There should be some screws that hold the two door knobs together. Install and tighten these screws and the two door knobs will clamp tightly to the door.
Another, less common way of securing the door knob to the door is using screws that attach to the timber of the door itself. The process is much the same however.
Tips and tricks
The first time you attempt this your are likely to make a few mistakes. But the one mistake you want to avoid is making your cuts to large and having them show on the edges of the latch or door knob.
If you cut too much out of the door and there is nothing for your screws to grab into, then you can use a timber filler or adhesive or even glue bits of wood back into the door. It will look messy until you install the door knob and latch which should cover all your minor mistakes.