Q&A / 

How to Replace a Door Knob

Door knobs are a fairly simple mechanical device found in just about every home, unless you live in a barn. In older homes built before the great WW II, most every knob was connected to a thin metal box that was carefully fit into the edge of the door. These full-mortise lock sets require great skill to install. Replacing them is hard because parts are tough to locate.

In the 1950's, a transition was made to what is now known as the tubular lockset or door knob. This lockset and knob combination required two simple holes to be drilled into a door. The hole sizes, for the most part, have been standardized over the decades and replacing a round tubular door knob and lockset can be quite simple.

Here is a link to one of my videos on fixing a broken door knob.

Degree of Difficulty: hammer-3-5

Step One: Inspect both sides of your existing doorknob and door. Look for screws, slots, small buttons, etc at the base of the knob or handle. Look for screws on the faceplates of any metal trim plates that are on the face of the door. Inspect the edges of these plates for small clips or detents. Discovering these things will help you start to disassemble the existing doorknob.

Step Two: The most basic tubular doorknobs and lock sets often have two screws on one side of the doorknob assembly. These screws will be on a round faceplate on the face of the door. Remove these screws if you see them. The doorknob on this side of the door should slide off revealing the inside workings of the lockset as well as the large hole drilled in the door.

Step Three: If you don't see screws on the faceplate, small spring-loaded slots on the knob handle may allow you to pull off the knob handle once depressed. With the knob out of the way, you can then remove the round decorative faceplate. This plate may be held in place by a small spring clip or metal detents in the rim of the faceplate. Use a wide flat stiff putty knife to gently pry off this faceplate.

Step Four: With one side of the knob off, you can determine the size of the hole drilled in the door. Measure the diameter of this hole to ensure the new knob you'll buy will fit in the door.

Step Five: Hook your tape measure on the edge of the door and measure to the top or bottom center of the large hole. You should get a measurement of 2 and 3/8 or 2 and 3/4 inches. This is called the backset. Be sure the doorknob you plan to purchase will work for the measurement you have. Most modern doorknobs will adjust to either dimension.

Step Six: Stop now and take photographs of what everything looks like in case you have to reassemble the knob. Look for other screws under the decorative plate you've removed that may pass through a large round metal plate. Unscrew these fasteners to gain access to the inner workings of the doorknob. Take additional photos as you remove more parts.

Step Seven: Remove the other side of the doorknob. It usually just slides out once all screws are removed that hold the two halves together.

Step Eight: With the knob out of the door, remove the spring-loaded latch that extends from the edge of the door into the center of the large hole. Two screws on the edge of the door allow you to remove this hardware. A decorative plate on the edge of the door may have to be removed first allowing you access to two hidden screws.

Step Nine: Purchase a new doorknob that will fit in the pre-drilled holes you now see.

Step Ten: Follow the instructions with the new doorknob to install it. Usually you follow the same methods above, just do it backwards.

Summary: The most important part of replacing a doorknob is making sure the new one will fit into the existing holes and slots you have in your existing door. Take the time to figure this out before buying a new doorknob.

Be sure to watch my video on Fixing a Broken Door Knob. Just click here.

Column: HT003


2 Responses to How to Replace a Door Knob

  1. Hi Tim:
    Loved the door knob thing. I have abundance of 1926 door hardware which was removed to refinish the doors. Now I have to clean this stuff. I am not sure I can even figure out how to put it back. Someday I do hope someone with lots of experience with balloon framing, old locks, constant cracks in plaster walls, wood floors that have gaps, on and on, will create a book on how to do all the good things to make the house nice again. I am really getting tired after 12 years and there is never an end. replaced one of the two (yah, 2 antique entrance doors) in the livingroom with a cheap metal one from Home Depot -- just for security and ease, Problem is that the extended door frame was a mystery to me, to the carpenter and to anyone I tried to hire to fix the door. Soon I will be removing it and putting back the old framing so I can have a much nicer front porch. One thing that I want to add is a keyless lock assembly -- any info on how this is different then regular hardware? Have a Terrific Christmas Holiday and lots of Good Eats! P.S. In 2013 after writing to you several times, I was able to buy the correct wenches for fixing my washer connections, old value in the basement, level my refrigerator so it would stop leaking and diagnose that the copper pipe was corroding the bathroom plumbing. Oxygen became the instigator because I was to dumb to understand that you must keep water in all the pipes at all times to prevent this. I had put off fixing the kitchen sink so I had no water in those lines. Now I have figured out why the hot water heater is leanking (valve on top), had managed to arrange for repair before the entire inside of my new water heater is corroded and will have the copper pipes replaced with the new plastic. Once something is removed from my list, something new has to be added. I hate old houses!

  2. My wife was telling me that we need to replace the doorknob on our bathroom door, and I was curious about how you would pick the right knob. It's interesting That you say to make sure that it will fit the pre-drilled hole that is on the door. It would be nice to measure it beforehand, just in case you don't remember the exact size.

Leave a Reply

You have to agree to the comment policy.