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Project Guide

How to Install a Peephole in a Door

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Measure Door for Peephole
A man uses a tape measure to measure and mark for the peephole.
  • Use a tape measure to locate the center of your door and mark the spot where you want to install the viewer. Be sure it’s at a height that’s convenient for all the members of your household. 
  • Double check your measurements before you drill. 
  • Spade bits are the most economical type for drilling a hole that's large enough. Twist bits can also be used but make sure the shank will fit your drill when using twist bits. 
  • Bits come in a variety of sizes. Be sure to select the size that will bore the diameter of the hole you’ll need for your viewer. Your viewer’s installation instructions will provide the size of the hole needed.
Drill the Hole
A person uses a bit to drill through the door.
  • Make an indention on your mark with a center punch or the point of a nail to keep the drill bit from walking when starting the hole.
  • When installing a peephole on a wood door, start drilling slowly from the exterior side of the door first, and stop when the tip of the bit sticks through the interior surface to keep it from splintering.
  • Take the bit and line it up with the edge of the door and wrap tape around the bit’s shaft to mark the correct depth to ensure that you don’t drill all the way through from one side.
  • Drill at a 90-degree angle until the tape line is reached, then use the pilot hole you just created to drill back out from the interior side to complete the hole.  

Tip: Using a step ladder will help you maintain a 90-degree angle. 

Install the Viewer
A person installs the peephole into the hole drilled in the door.

Door viewers usually consist of a lens and a barrel. The lens is the part with threads on the outside. The barrel is the part with the threads on the inside. 

  • Insert the barrel into the hole from the interior side and hand-thread the viewer together. Then, insert the lens into the hole from the exterior side of the door. 
  • If the barrel fits the hole too tightly to rotate, remove it from the hole. Put the drill bit back into the hole and run it for a few seconds to clean it up and enlarge it very slightly. In some cases, there will be a decal around the barrel that causes it to be too tight for the drill size recommended. If this is the case, remove the decal before enlarging the hole.
  • Apply a small bead of silicone sealant around the backside of the lens to help seal out moisture.
  • Tighten with the tool provided, or you can use a coin. The viewer should be flush with the door and snug.
  • Clean off any sealant the peephole squeezed out before it dries and be sure the lens is clean.

Installing a peephole is an easy project that can be done in just a few minutes. Looking for a product to complete your project? We have options to deliver online orders when and where you need them.