How to cut dovetails

Let's take a pine seachest for a working demonstration of how to cut dovetails.

You will need a marking gauge, sliding T bevel, a fine tooth saw (carcass saw/DT saw/tenon saw), chisels, mallet, coping saw or bandsaw.

1. Starting with the tail board, lay out the thickness of your connecting board (plus about 1/32) with the marking gauge on both sides of your board.  you can use a pencil line, but I like to scribe with a sharp blade in my gauge.

2. Lay out the tails however you like...you can calculate exact dimensions, make them different size and spacing or just do them free hand.   It only matters what function and appearance you are interested in. Don't make the tail angle too wide...too much and you run the risk of a weak tail.

However, the important part is to cut them square on the edge.   You won't notice if the angle of the tail is a little off, but the edge must be square or there will be a gap in the finished product.

Mark the waste with an X on both faces and the edge...you will thank me.

3. Use a square to carry the lines over the edge. This is your most important guide line for the saw.

4. Cutting on the waste side of your line, saw to the scribed mark.  This isn't crucial on the tails but gives you practice, so you can do a flawless job on the pins. Remember, the important part is making the edge cut square to the face.

edge cut perfect

5. OK, now you have to get rid of the waste.  In this example, I use my bandsaw to remove right to the line since this project in pine allows for a little slop.  You might want to saw just in front of the line and clean up with a chisel if you're looking for perfection.  Again, cut on the waste side of the line.

 


6.  Once you have the waste cleaned out, it's time to mark the pins.   Mount your pin board in the vise and lay the tail board on it.  Stick something under the board to hold it level while you mark.   This board is 16 inches, so I could hold it with my left hand while marking.  You might want to clamp it with smaller stuff.

I use a marking knife, but a sharp pencil might be fine also.  It is just important to make an accurate transfer of the tail to the edge of pin board...all highly visible in finished product.  Drop the lines down to scribe line with a square.and mark the waste sections with an X again.   Nothing more frustrating than going to all that work to cut on the wrong side of the line and leave a gap in the joint.  A repairable problem, but a pain in the bum.

7. Cut the pins, this is where you need to be accurate.   There are different ways to attack this and I change my approach depending on how hard the wood is.  For pine, I put my saw on the corner of board (on the waste side of line) and line up the edge and scribe points with my laser-like eyeball.  Once you have a couple of strokes going, drop the far end of the saw down as you go and finish up square to the board.

8. Remove the waste again...if you don't have a bandsaw, a coping saw works fine also.  Now you are ready to fine-fit the joint. Work only on the pin board, unless there is some obvious need to fix something on the tail board.  If you start cutting on both boards, you will end up with a disaster.  Be patient, check the fit, mark where you need to trim and take just a little at a time.

9.  Dry fit the whole thing and make adjustments as necessary then glue up.  Notice the many glue surfaces...best to use a small flux brush to spread it. Clamp it both directions, of course.

After a couple coats of amber shellac, the job looks good.  All hands aboard!