How to cut box joints

How to cut a box joint with hand tools, part 2

We saw in a previous post how to cut on the first board the straight pins and sockets of the box joint. Now I am going to use that first board that I have already cut, to mark the size of the sockets that I have to cut in the second board so both boards fit to make the box joint.

I’m going to put the end of the first board on the side of the second board flush whith the border. And I mark the depth of the sockets I have to cut. And now, by placing on the second board the sockets and the pins that I have already cut in the first board (1), I can mark the size of the pins that I have to leave and the sockets that I have to cut in the second board.

Mark the sockets needed to fit the box joint

As we can see in the picture, the lines that I draw belong to the pins that I should leave, so I should avoid cutting on those lines.

Finish marking the sockets of the box joint.

Then, with the dimensions of the pins and the sockets that I have already marked, I draw a mess line on the wood I want to eliminate (the sockets), and I draw a “V” on the wood I want to leave (the pins). In addition, I am going to draw a small triangle on the side of the lines that is in the area of the mess line (in the area of the sockets). I want to cut next to the lines and in the area where I drew the triangle (2), the side of the mess line. Once I have marked what to cut and where to make the cuts, I extend the lines on the head of the board (3), and on the other side of the board (4). In addition, I have to extend the depth line of the cuts (5) to the sides.

Cutting the wood of the sockets of the box joint.

With all the lines marked and being very clear where I am going to cut, I place the board in my homemade vise and start cutting following the same procedure as when cutting the pins and the sockets of this box jointon the first board: I make all the cuts from one face of the board with the tenon saw tilted back (6); I make all the cuts from the other face of the board also with the saw tilted back (7); I finish the cuts with the saw cutting horizontally (8); and I remove most of the wood from the sockets using a fret saw (9).

Cut and adjust the sockets of this woodworking joint

Now, as I did with the first board, I have to adjust and clean the base of the sockets using a chisel (9b). Then I can start adjusting the width of the sockets so that the pins of the other board fit perfectly to make a nice box joint.

Adjust the size of the sockets with the chisel.

With the chisel vertical and close to the line, but not on top of it, I will cut vertically downwards. I start by marking on the side of the line (10a), I cut slowly downwards (10b), and finish cutting when reaching the base of the socket (11). I cut the shavings at the base (12) and do the same next to the rest of the lines.

Test fit and adjust the box joint with the chisel

Once all the cuts have been made, the next step is to test how the joint fits, and to use the chisel to make the necessary adjustments until the box joint fits perfectly. The trick is to make sure not to over-cut at any time, and to use the chisel to gradually approximate the size of the sockets until the pins of the other part of the box joint fit perfectly.

-> Back to the first part.

error:
Scroll to Top