How to Install a Door Knob and Lock: Step-by-Step Guide
Published Date: Jul 24, 2025
Whether you’re replacing old hardware, fixing a broken latch, or upgrading your home’s security, it’s important to know how to install a door knob lock correctly. This guide breaks down the tools you need, each step of the process, and when it makes more sense to call in a pro.
Getting Set Up: Tools for Installing a Door Knob with Lock
With the right tools on hand, the job feels more straightforward from the start.
Here’s what to prepare:
- New Door Knob with Lock – Your door lock kit should include the latch, two knobs, strike plate, and screws. Make sure it fits your door’s thickness and backset (the distance from the door edge to the center of the hole). Most doors use 2-3/8" or 2-3/4".
- Phillips Screwdriver: Most modern door knob locks use Phillips screws.
- Tape Measure: To double-check hole placement.
- Pencil: For marking.
- Chisel (if needed): You might need to trim the latch plate area so it sits flat.
Step-by-Step Instructions: How to Install a Door Knob and Lock
Let’s go through each part of the process clearly, so you won’t feel lost at any point.
Step 1: Remove the Old Door Knob
First things first — take off the old hardware. If you’re unsure how to do this safely, check our helpful guide on how to remove a lock from a door knob. Usually, you just need to unscrew the inside and outside handles and then slide them off the door.
Step 2: Check the Door
With everything removed, check the holes in your door. Your new door knob with lock should fit into the same openings. If something doesn’t line up, you might need to slightly widen the hole or adjust the latch area with a chisel.
Step 3: Install the Latch
Insert the latch into the hole on the edge of the door. The angled part should face the direction the door closes. It should sit flush. If it doesn’t, gently trim the area using a chisel.
Step 4: Add the Door Knobs
Push the outside knob through the latch. Then line up and connect the inside knob. Hold both sides in place and insert the screws through the holes in the inside plate.
Step 5: Tighten the Screws
Use a screwdriver to secure the knobs. Make them snug, but don’t overtighten — that can strip the screws or crack the plate.
Step 6: Attach the Strike Plate
Go to the door frame. Remove the old strike plate and screw in the new one where the latch hits. It should be aligned so the latch slides in smoothly.
Step 7: Test the Lock
Turn the handle a few times. Lock and unlock it. Open and close the door to see if everything moves cleanly. If anything sticks, recheck the latch and strike plate alignment.
If you’ve been wondering how to install a door knob with lock, these steps should give you the confidence to get it done right.
What Can Go Wrong During Door Knob Installation (And How to Get It Right)
Even a straightforward project like installing a door knob with lock can go off track if a few small details are missed. Here are some common mistakes — and how to avoid them, especially if you’re doing this for the first time.
- The Latch Doesn’t Sit Flat: If the latch sticks out, the door may not close properly. Test-fit it before screwing it in, and trim the area with a chisel if needed.
- Wrong Screws: Using different screws can leave the knobs loose or uneven. Stick with the ones provided in your door knob lock kit.
- Not Measuring First: Skipping this step could mean buying the wrong lock. Measure your door’s thickness and hole spacing before you shop.
- Overtightening Screws: Cranking too hard can strip threads or crack the plate. Tighten just enough to keep everything secure without forcing it.
Wrapping Up
Installing a door knob with lock is a manageable task, but precision matters. This guide is here to help you feel prepared and ready to handle it. Still, not everyone wants to deal with alignment issues or stubborn hardware. If that’s the case, a locksmith for residential can handle the job without the guesswork. Sure Lock & Key takes care of these fixes every day — quickly and reliably. Feel free to reach out anytime you need expert installation or honest advice.