Drones are like all other NAFs in that they begin with a board which is large enough to accomodate its bores and 1/4" walls, and is of sufficient length to yield the desired key.  Drones are routed like single bore flutes only there are two of everything.  The TSH's and SAC exit holes are milled with a 1/8" end mill using a cross slide vise. 
The slots are squared off with a file. 
The results are seen below.  Ramps are created with a chisel almost as wide and the TSH.  Use the chisel bevel up. 
After sanding the bores, and checking for flatness, spread Titebond III on the walls of the flute. 
Done worry about a little extra glue. You will swab out any extra. 
Clamp and let dry.  As soon as possible after clamping, swab out any extra glue. 
Initial shaping can be done with an angled router bit with a bearing. 
Observe your safety techniques very carefully. Take your time and take small cuts only.  Note the shape of the end of the flute after initial shaping. 
This is a good time to swab the interior of the bores with the finish of your choice. I use shellac. Note the layout marks used during routing. 
I shape drones with hand tools. Here a small block plane. 
A jack plane.  A jack plane. 
The jack plane is used for reducing wall thickness as well as for general shaping.
A draw knife is useful if you have the skill (and nerve) for it. 
Spokeshaves are good for all flutes. 
Lean back into the spoke shave to save effort.  A good cabinet scraper is very good for fine shaping and rough finishing just before sanding. 
The flue is milled to .032" with a dremel type tool and a straight bit. 
This is a large drone (1.25") and so the finger holes were drilled to accomodate playing comfortably.  Notice that the flute side is a little shorter than the drone side. | 
