Also known as Box Joints. Not saying this is the “perfect” way to do these, but, this is how I do them.
First off, I get the four sides all milled to size. Nice when they are the same width and thickness
So, for this little “How to”, I have these Pine boards. I made them about 3/8” thick, and all are about 3-1/2” wide.
Boards can be about any size, but they need to be close to the same size no matter how thick or wide they are.
I start with the “long” sides. I clamp them up inside to inside faces. I then first mark roughly the thick ness of the shorter board on one end of the stack. Then square a line across…
AsI have a bit of trouble holding the two square to each other. Next, I get out a chisel, and use it to mark the fingers out..
For this project, I used a 1/4” mortise chisel, but, about any width chisel can work. I start on one end, and work my way across. You can also start at each end and work towards the middle, adjusting the middle to fit. The chisel will also be the one to chop out the waste. I then use a square, and layout the cut lines down to the Base line. I keep the sides pieces together for this, as I want them to match. Then I lower the two sides a bit in the vise, and get a saw out..
I have this little back saw for the job, but about any saw can work as long as it can cut straight. You can even do this with a bandsaw, just try to split the lines is all. Next I take the sawn boards, and open them up like a book,
These are the “insides” of the box. I also mark which is the top and bottom edges.
helps later with the fitting. I can then set aside one of the sides, for now. I grab the square and a knife..
About 3-5 passes with the knife along the base line. Makes a “knife wall”. I do this to both faces. On some of these joints, I can saw the corners off..
Since the saw is handy. Next, a bit of chopping is done. Nothing real fancy, but..keep the bevel of the chisel pointing away from the knife wall. I start by peeling a layer off towards the wall, starting about halfway back…then a chop in the wall area. The peeled off part gives a place for the bevel to go. Keep this up until..
You get about halfway down. You can either leave the end on, or off..
As long as you give the knife wall one more chop…do not get greedy, all you want here is for the waste to snap off..LATER. If it does at this point, you will get “blow out” on the other face. Ok, do the entire side, then flip the board over, and repeat…
If you remove the end piece of the waste, it will tip down like this, a second hit will remove the little block. If you do leave the end in place, that little block will fly back at you. I then can pare the finger until they look spiffy..
Happy with the look? Ok, remove this board from the clamp, replace it with a short side board ( marked for “Inside” Top and Bottom and a corner number). Tricky part next. I hold the completed fingers where they will be going, I take a sharp pencil, and trace on the short board where the fingers will go…
Supposed to look like this after squaring the lines. I also include the base line. Then, this time around, you want to saw on the waste side of the lines, LEAVING the lines. Much easier to pare a bit to fit. Then, just chisel away the waste, like before. One face 1/2 way, flip over, and complete the chop. test for fit..
IF it is a bit too tight, a pass with the sharp chisel to pare to fit. One corner done, three to go. Takes about the same amount of time as it did to read this blog.
Remember, use a sharp chisel, with the bevel away from the base line, knife wall. First time through, you can split the lines, but the matching fingers need to be sawn on the waste side, leaving the lines.
Best thing? I can use this shop tool..
And work sitting down on the job. Any questions?
-- A Planer? I'M the planer, this is what I use