How to Install a Mail Slot

Decide where to put the mail slot. Postal regulations require that the mail slot be placed a minimum of 30 inches (76.2 cm) from the ground, high enough for the letter carrier to reach comfortably. If you have a solid wood door, you can place the mail slot anywhere, but if you have a paneled door, you'll need to install it on a strong, non-paneled part of the door. Hold the mail slot at the desired height on the interior side of the door, and make a small pencil mark along the bottom of the mail slot.

Find and mark the center point of the door. Measure the width of your door to find the center, and then make a small pencil mark at the height you've chosen for the mail slot.

Mark the height. Use a measuring tape to measure up from the bottom of the door to the center point at the height you've chosen. Now measure that same distance a few inches to left and right of the center point. The three guide marks will ensure the mail slot is level.

Align the center point of the mail slot with the center point of the door. Measure the width of the mail slot to find its center point and then hold the slot against the door, matching up that point with the center point you marked earlier.

Hold the mail slot in position and trace around it with a pencil. Keeping the center points of the door and the mail slot lined up, align the bottom of the mail slot with the height marks you made earlier. Then use a pencil to trace the perimeter of the slot.

Measure the distances between the edge of the mail slot and the four edges of the inner flap. Write the measurements down.

Mark the inner flap measurements on the door. Mark the measurements with a pencil inside the larger outline of the slot. Connect the dots with pencil lines using a ruler.

Drill starter holes. Starter holes are necessary to enable you to cut the hole with a jigsaw. Fit your drill with a large, flat drill bit (a paddle bit) about 30 mm wide. Drill four holes straight through the door, starting each hole just inside each corner of the flap outline. Drill until the bit begins to come out the other side of the door. Then drill through each hole from the other side of the door, and blow the sawdust out of the holes.

Cut the hole for the flap. Insert the jigsaw into one of the four starter holes, and carefully cut all around the penciled-in outline of the inner flap. Try to keep the saw right on the line all the way around. When you've finished, push the chunk of wood out of the door.

Sand the edges of the hole. Use sandpaper to make sure the inside of the hole and the edges around it are smooth.

Mark the lug holes. Precisely measure in from the edges to the center of the bolt fixtures (lugs) on the back of the mail slot, and then mark this position within the outline on the door.

Drill bolt holes. Determine the size of the bolts or that will go into the lugs--the directions included with your mail slot should have this information--and attach a twist bit (a screw-type drill bit) of this same size to your drill. Drill a hole through the door on the marks you made for the lug holes.

Drill lug holes. Fit your drill with a flat (paddle) bit that is about the same size as the lugs on the mail slot. Position this bit at the center of each hole you made in the last step, and drill only halfway through the door. It's important to keep your hole level, so drill slowly and carefully.

Screw the bolts into the lugs.

Insert the mail slot into the door. Push the slot into the door from the outside of the door. The inner flap should fit perfectly in the hole you cut, and the bolts should go through the bolt holes all the way through the door.

Trim the bolts if necessary. The bolts should protrude out of the door only far enough so that the nuts can be securely screwed onto them. If they protrude farther, trim them.

• Mark where to cut. Press the nut flat against the door next to the bolt. Use a pencil to mark the depth of the nut on the bolt. Do this for each bolt.
• Use a small hacksaw to cut through the bolt at the mark.

Screw the nuts tightly onto the bolts.

Attach the draft excluder to the inside of the door. Push the draft excluder into the inner flap hole on the inside of the door, and use a drill to attach it to the door with screws.