How to Add Keys or Splines to a Mitered Box — Cat Box Completed

A box constructed with miter joints, like everything else; has its plusses and minuses.  On the plus side it allows you to use a single piece of wood so that the grain pattern of it can flow around the corners.  In the first blog about this custom box I explained my method for doing that on the tablesaw.  You can then cut a slot across those mitered corners and insert a piece of contrasting material to reinforce the weak, end grain to end grain of the mitered joint — that is the primary minus to this type of joint.  There are a few different ways to go about this.

You can buy a specialized jig like this one from Rockler Woodworking or you can take the route I took and make your own.  Mine is made from some scrap pieces of MDF and 5/4 Poplar.  It’s important to use a blade such as rip cut to create a flat kerf  for the spline to glue in to.  As you can see in the center picture I’ve been using this one for quite some time!  Lines on the cradle allow me to line up the work, once the stop block is clamped down simply rotate the box to cut all four corners.  You can vary the depth to add even more of a stylized look to the work — being careful to not cut through the box!

After the cuts are made, plane down your material for the splines.  I start with a power planer then fine tune with a hand plane.  Here’s my spline cutting and gluing set up.

Needed "stuff" for cutting and glueing up the splines/keys.

Needed “stuff” for cutting and glueing up the splines/keys

Starting at the left is the Old Brown Glue which is my preference for this work.  Since it needs to be heated the coffee cup with hot tap water is used for that.  I use a small brush to get the glue into the cut without making a lot of mess.  A piece of Marlite is great for glue ups since it glue won’t stick to it.

Cutting spline/key

Cutting spline/key

To cut the spline/key I’ve found that a bench hook with an accurate 45 degree kerf paired with a Japanese razor saw is a good choice.  The glue is put on a piece of scrap wood and brushed into the cut, then a small amount is also applied to the spline/key.  Keep in mind that you want it to seat all the way in the cut and too much glue may prevent that.  Once dry, a block plane makes quick work of trimming it flush with the sides.  The grain of the key runs diagonally so take a light cut towards the box, not the outside. The corners of my blade have been radiused to prevent them from digging into the work.

Now that this step is complete it’s time to separate the lid from the box.  Again, I use the tablesaw for this.  The technique is to cut the long sides of the box completely through, then lower the blade so that you leave 1/16″ or so of the box uncut.  Doing that prevents the box from closing on the blade as the cut is finished which can result in a snip at least or a serious kick back at worst.  This remaining piece is easily cut with either a utility knife or flush cut saw and then planed flush.

Fitting Hinges

Fitting Hinges

Other than the finishing process which in this case was Platinum Shellac and wax all that remains is the hardware.  The hardware was installed after the shellac was cured thoroughly, I use an air brush for my boxes.  Hinges were installed using a combination of a trim router and jig followed by fine tuning with hand chisels and marking gauge.  This is where all of your effort can be  lost so I tend to be very careful at this point.  Pretty difficult to conceal a hinge mortise that’s been misplaced!

Gimlet in use

Gimlet in use


For the tiny screws used for the hinges, hasp, and nameplate my preference is using a gimlet.  Much easier to control than an electric drill — that being said though I will use a small Vix bit to start the holes centered in the hinges followed by the gimlet.  Screws are always lubricated with beeswax since I don’t relish trying to drill them out should they break.  Also a wise choice to use a steel screw in the hole first if the hardware screws are brass.

Happy to say, all went well and the box was mailed out Thursday to my client in North Carolina.  This has been a while in the making and thankfully, she was very patient.  She knew she wanted the Leopardwood which took me a while to get plus the Mechanical Cellarette project had priority over this one.  Looking forward to getting back to work on my personal project, the Armoire.  I’ll end this post with a few pictures of this completed project.



About woodworksbyjohn

I'm a retired woodshop teacher. I build one of a kind furniture pieces and custom picture frames. You can see some of my currently available work, boxes, carvings through my Etsy store: Contact me about your project -- always up for the challenge of unique work.
This entry was posted in Etsy custom order, Jess'sCatBox, Mitered Box, Tutorial and tagged , , , , , , , . Bookmark the permalink.

1 Response to How to Add Keys or Splines to a Mitered Box — Cat Box Completed

  1. Pingback: Cigar Presentation Tray — with a Cuban Influence! | Woodworks by John

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