A Home Made Mitre Box

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[edit] A Home Made Mitre Box

Here is a little thing that has been around for centuries. Master cabinet makers used them to create works of art for the crowned heads of Europe. Yet the only people who seem to use them now are plasterboard fixers when they are cutting their cornices. (Apart from myself and maybe you of course :-)

I have had a couple of those hand miter frame things, with the long back saw and adjustable swing on the saw. The cheap ones are no good and now for the price of a good one, you can get a power saw.

I always make these myself, wouldn't dream of buying one. Usually made out of scrap timber. They can be nailed or screwed together. The little bits across the top maybe using very fine nails or panel pins to fix them. If you use scrap ply for the top it is ideal as it does not split.

The three pieces are fixed together in long lengths, then when the whole thing is made, mark out your two 45 degree and maybe even a 90 degree one.

Make the guide cuts with the same saw that you will use for the rest of the work. A small tennon saw for small beading. For skirtings and architraves I usually us my Sanvik panel saw, a 22" with 9 teeth per inch. If the saw is sharp you will have little trouble.

If you are cutting small stuff, make the miter box small also, suit the job. In this case you also use a smaller saw.

After you have been using it a while, the guide cuts start wearing and your cuts start getting sloppy. Throw it away and make another one in less time than it takes to go to the store.

Let's say that you want to make an eight sided picture frame. The angle at the joints is not a true miter, which is 45 deg. in this case the angle will be half that at 22 1/2 deg. So for even just one picture or mirror frame I would build a separate miter box, with the angles at 22 1/2 deg. When two pieces of moulding join at an odd angel, that is not 90 deg. The correct name for it is a Bastard Miter. (You can also use the term as an adjective, if the joint is giving you trouble :-).

I usually only make up these now when I have a few cuts to do that I can't do with my power miter saw. For example skirting deeper than my power saw will cut. As I have said, I do not have a compound sliding mitre saw, but I manage OK for the few jobs I would need one for, with one of these home made boxes.

On the right is a sketch of the end view of a purpose made box for a crown mold.