Canadian Woodworking

Walnut mailbox

Author: Jim Sinclair
Photos: Jim Sinclair; Lead photo by Vic Tessolin
Illustration: James Provost
Published: April May 2010

For those of you who are lucky enough to get home mail delivery, a handmade wooden mailbox gives you a chance to show off your woodworking skills to all who come to your front door.

Design Considerations

Most wall-mounted mailboxes have lids that cover the entire box open­ing and slope forward. This keeps the rain off the mail and encourages the rain to run off away from the building. Unfortunately, many mailboxes are sized to accommodate little more than #10 envelopes. Whenever any larger object, such as a newspaper or maga­zine, is placed in the mailbox there is a good chance the lid will remain open. No big deal in good weather, but it can be an issue with rain or snow. This mailbox is designed to solve that problem. The typical oversized envelope that shows up in my mailbox is 12″ by 9″. A full size newspaper with its single fold is about 13″ by 12″. It would be nice if these items would fit in the mailbox without the need to further fold them. This suggests an interior space that is at least 13″ by 12″.

Mailboxes reside outdoors. This means that wood movement is a signifi­cant issue that must be addressed in the design. The lid can be made of a single piece of solid wood. Wood movement will not be a problem for the lid since it is not joined to any other part of the box except by hardware. For the rest of the box a simple frame and panel approach should remove any wood movement issues.

I chose walnut for this mailbox but feel free to select whatever wood suits your fancy. There is nothing particu­larly special about the choice of wood for this project.

Resawing the panels
 This technique will allow you to produce matched panels for the mailbox.

Cutting the Angles
Set your mitre gauge to 20° and cut off one end of each of the top side stiles. Then rotate and flip each one to cut the other end parallel and to length.

Cutting the angled stiles
 Using a stop will help to keep the parts all the same length.

Setting the table saw
 Using the actual piece to set the angle on the saw blade is the best way to achieve accurate results.

Mark your spot
 Mark your mortise locations clearly so you don’t get confused when you start cutting them.

Cutting the angled cheeks
 Using a tenon jig available for your table saw is the easiest way to get accurate results.

Trimming the waste
 Start with the band saw to trim the tenons and finish off with some paring cuts with a sharp chisel.

Cutting the long slots
 Use guide lines on the fence to establish where to start and stop the cut.

Cutting the bottom panel slots
 Use a backing board to push the work through the bit to ensure the grain doesn’t blow out the back.

Laying out the hardware
 Some masking tape will help protect the finish while laying out the screw locations.

Basic Preparation

When doing your initial selection of where to cut the parts from basic stock, make sure you select a nice looking sec­tion for the lid. Mill all the parts except the panels to their basic width and thickness, then cut all the non-angled parts to length. If you think you might need some practice cutting tenons, leave some of the stiles over long for now and do your first tenons on them. By leaving them over long you can cut the tenons off and try again if you don’t like your result. Once you are happy with your results, cut them to length and cut the tenon on the other end. The angled ten­ons in particular are ones you might want to practise.

Preparing the Panels

To create the seven panels you need, cut some boards roughly to length, joint one face and one edge. With the jointed face against the bandsaw fence and the jointed edge against the table, resaw a panel off the board to a thick­ness slightly over ¼”. Joint the newly exposed face to remove any saw marks and resaw off another panel. Continue until you have enough panels. An extra one or two panels at this stage will give you some flexibility when you decide where to position the panels. A pair of attractive adjacent panels from a single board might be worth setting aside to be the two front panels. When you have all your panels, plane them down to ¼” ready for smoothing. Your goal is to end up with smoothed panels that are just less than ¼” so they fit easily in the ¼” groves. You may want to wait until the vari­ous frames can be dry fitted together before you cut the panels to their final size.

Note that for the bottom panel you will have to remove a ¼” by ¼” section from each corner of the panel. This can easily be done on a bandsaw with the fence set at ¼” and a stop made from a piece of ⅛” hardboard clamped to the fence that only allows the piece to proceed into the blade ¼”.

Prepare the Lid

The lid has a simple bull-nose edge on the front and the two side edges. The back edge has a bevel. Rout the two side edges first. Use a large sacrificial push block to keep the lid square to the fence and to avoid tear-out on the end grain, then rout the front edge. All that is left to do on the lid is the bevel on the back edge. Cut this when you cut the rest of the angle cuts.

With the mitre gauge still set at 20°, cut the bevel on the top of the four rails and the tops of the two side pan­els. Return the mitre gauge to 90° and cut the rails ½” over length. You will find that leaving the rails an extra ½” long until after the mortises have all been cut and fitted is a good idea. The extra material will provide some extra support for what will eventually become relatively weak end grain at the bottom of the rails below the panel groves. This way the rails should stay intact despite the stresses applied during dry fitting.

An off-cut from one of the rails makes an effective template for setting the blade angle on the table saw to 70° in order to bevel the tops of the front and back top stiles. Lower the blade to just clear the top of the stiles, set the rip fence so you remove only enough wood to create the bevel and rip the two pieces. A push stick would be a really good idea on this cut. Re-adjust the rip fence setting and raise the blade height a bit to cut the bevel on the back edge of the lid.

Cutting the Mortise and Tenon Joinery

Cutting the mortises and tenons associated with the square stiles is straightforward. A minor detail is that the tenons on the two top stiles at the front and back should be low­ered a bit below center in order to leave a bit more wood at the beveled top of the rails. Just keep in mind when laying out the bottom mortises on the rails that there is an extra ½” at the bottom of each rail that you will trim off later. When cutting a number of mortises I like to mark on the wood approximately where all the mortises will be cut with a pen­cil. This allows me to look at the overall set of work and to do a basic sanity check. It also serves as a last minute check that the piece has been oriented correctly when it is ready to be routed. In this case working with walnut, I used a white pencil.

The mortises and tenons for the top side stiles are some­what trickier. I chose to go with keeping the mortises in the rails square, and cutting the tenons at an angle on the stiles. Given the angle on the tenons they need to be posi­tioned lower than the center of the stile in order to not break through the surface of the bevel on the top of the rails. Start by cutting the tenons on the stiles. Cut the main shoulders on the table saw using a mitre gauge set to 20°. Next set the stock support on the tenoning jig to the appropriate angle to hold the end of the angled stile flush with the top of the table saw. Remove all the inside cheeks, then adjust the positioning and remove all the outside cheeks.

Use a bandsaw to cut the tenons to width. For the small shoulders remove most of the material with the bandsaw. Use a chisel to pare away the waste left by the bandsaw. Use the long shoul­ders created by the table saw to guide the back of the chisel to form an even shoulder all around the tenon.

With the angled tenons cut, use the tenons to lay out where the mortises should be cut in the rails.

Once all the tenons are cut, they need to be mitred on the end at 45°. This is to accommodate the fact the tenons all meet other tenons at 90° inside the mor­tise. By mitring the ends of the tenons we maximize the glue surface area and length for both tenons.

Adding the Panel Groove

A ¼” straight bit in the router table is used to cut the grooves that the vari­ous panels will mount in. All the slot cuts can be done using the same setup except for the bottom panel grooves in the four rails. Raise the bit to ¼” high and set the fence ¼” back from the bit. I cut the grooves in two passes using a piece of ⅛” cleated hardboard to raise the work piece up for the first pass. The hardboard is removed and the piece is run through again for the second pass. When cutting the grooves, run all of the pieces with the outside of the piece against the fence. This will ensure that the grooves are all at the same location, even if the setup is slightly off.

For the stiles and muntins, the groove runs the full length of the piece. Simply rout the piece from one end to the other. For the rails, all the grooves except for the bottom panel groove can be run from one mortise to another. Draw a guide line on the router table fence to show where to lower the piece down over the router bit to begin the cut. You should be able to feel when the bit completes the groove and runs into the mortise space. If you are not feeling comfortable when to end the cut, draw a stop guide line on the router table fence.

Cutting the bottom panel groove is a bit more complicated. Remember that you have an extra ½” on the bot­tom of the rails. The fence needs to be moved back to ¾” from the bit. Attach an auxiliary fence to the router fence with no bit clearance gap. This will give something for the bottom of the rail to run against for the entire cut. Mark a guide line on the auxiliary fence to show where to stop the cut. Use a large square sacrificial push block to keep the rail square with the fence. For the first half of these grooves you will be able to push the rail into the bit, and stop at the guide line. For the other half you will need to mark a new guide line on the auxiliary fence and lower the rail down on to the bit using the second guide line for positioning and then run the rail over the bit. This second set of cuts will run into the push block as you clear the work piece.

The Crown

The crown is slightly narrower than the top stile at the back that it attaches to. This leaves a slight beveled lip that the lid rests upon. The actual shape of the crown is flexible. You can let your creativity loose on this part if you feel so inclined. I did a simple angled cut to the crown on either end. Once the shape of the crown is complete, pro­ceed to gluing the crown to the top back stile. Although dowel joinery is not necessary for this edge to edge glu­ing, I used a few dowels to help with the alignment.

Dry Fitting

An initial round of dry fitting the box will allow you to refine the mortise and tenon joints. Pay particular atten­tion to the tenon intersections inside the mortises. Make sure that the stiles seat firmly in place when both tenons are inserted. Some minor fitting should remove any binding between tenons. Once you are satisfied with the dry fit it is time to trim the bottom of the rails to final length before doing the final sur­face preparation for finishing.


Depending on its location, a mail box is going to be exposed to varying degrees of sun and weather. A finish that provides protection from both is necessary. I chose to go with a combi­nation of a pigmented stain followed by a spar varnish with UV blockers. The stain imposes a consistent wood colour that should stand up to exposure to sunlight. It also provides the added benefit of hiding the light coloured sap wood I had in the stock for this project, particularly in the board I used for the panels. Spar varnish is an exterior grade finish with good weather resistance, traditionally used for above the water line marine applications. Spar varnish is resistant to fading and cracking from sunlight. By picking a spar varnish that also contains UV blockers the fin­ish will provide UV protection for the underlying wood. One downside of spar varnish is that it only has fair resis­tance to scratches, but this shouldn’t be much of a problem for a mail box.

I prefer to finish most of my projects before assembling them. I find I can focus on carefully producing a clean, even finish with small components more effectively than I can with a fully assembled piece. There are no hard-to-get-at locations and drips are not a problem. The joinery needs to be pro­tected from the finish and so I generally tape over the areas that will be glued to protect the surfaces.

Assembling the Box

Before doing a final post-finishing dry fitting of the box, hand plane all the panel edges down just a bit to remove any finish that may have built up on the edges. Use a block plane to put a slight chamfer on the panel edges. This will help protect the panels and the grooves during assembly. Do a final check to make sure that the panels are all slightly under-sized. This will ensure that there is room for the panels to move within the assembled frames.

Now do your final dry fit of the whole box just to make sure nothing has gone wrong during finishing. A build-up of varnish in the wrong place is something you don’t want to discover with wet glue all over your joinery. Start by assem­bling the two sides. Each of the sides is a simple frame and panel assembly with the slight twist that the upper stile is at an angle. A bit of glue on the tenons and inside each mortise is all that is needed here. A cotton swab or a small acid brush works well for getting a light, even coating of glue on the matching parts. Use soft padding on your clamping cauls such as cotton or leather to pro­tect the spar varnish finish. It won’t be hard enough to withstand direct clamp­ing pressure. Once the side assemblies are dry and the clamps are removed you are ready to move on to assembling the rest of the box. Make sure that the mun­tins are centered. This way both panels have room to move. Again, use soft pad­ding on your clamping cauls to protect the finish.

Attaching the Lid

The lid is attached to the crown using some commercially available hinges. The hinges have over-sized holes that the screws pass through. The round head screws have a smooth flat bot­tom that moves easily against the hinge surface. The combination of the over-sized holes and the flat bottom on the screw head allows wood movement in the lid and crown to occur without put­ting undue stress on the screw joints. Without features to compensate for wood movement, stresses on the screws would eventually weaken the wood around the screws and they would come loose.

When laying out the positioning for the hardware on the lid and the crown you will find that temporarily add­ing some masking tape over the finish makes the job much easier. It also pro­tects the finish while you are drilling the pilot holes for the screws.

Mounting the Mail Box

Mounting details will vary depend­ing upon what choices you have at your location. In my case I used a masonry drill to put a pair of holes partway into the brick and put in some plastic screw anchors. I then drilled a pair of clear­ance holes through the upper back stile near the top of the stile to avoid the back pan­els. Finally I used some round headed screws to attach the mail box to the wall.

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