This photo illustrates two things. Firstly, I use a cheap potable workmate clone workbench to hold the drum during shaping. It's inexpensive and I can get all around it as I change planing positions. I clamp one, or both ends (if the drum is short enough, with a cheap hold-down that clamps through one of the holes in the work surface.
The second thing is that for the initial shaping, removing the corners where the staves join, I have found either a spokeshave or (in the following photo) a hand planer to be effective.
The first shaping task is to remove the corners and make the drum shell roughly round. The spokeshave is ideal for planing convex surfaces and has the advantage that it can be set to not take off too much wood at a time. It can be a lot of work though.
An alternative is an electric hand planer. It will remove the corners with much less effort, however unless you are experienced with this tool (and I'm not very experienced with it), it's quite easy to remove too much wood, or carve troughs across either end of the drum if you are not careful to keep the planer level when crossing the ends. I found it safest to plane from the middle towards each end, and concentrate on applying pressure to the rear of the planer as I approach the ends of the drum.
Because the planer is so cumbersome, I follow up with a long base hand plane.
This plane is probably technically a jack plane, not a smoothing plane, but it's the longest I have. The plane is kept sharp, and set to take a very thin curl of timber. Happiness is a sharp plane. I found this task very satisfying.
This ensures that you cant take too much wood at a time, and that you can straighten the sides. You will end up with a fairly smooth, rounded surface. With enough practice and patience you could probably get a fine finish, however for that I used a cabinet scraper.
A cabinet scraper is a rectangle of metal that has had a hook burnished onto each edge. This hook acts as a mini plane and scrapes a very fine curl of timber. If you use a lightweight scraper (0.6mm) you can easily hold it in a curve and this will not only create a smooth surface, but will also even out any high places across the arc of the drum side.
I spent a good deal of time with the hand plane and the cabinet scraper to produce a fine finish. Don't rush this task, time spent here will produce a much finer finish.
Leveling the top and bottom rim – more to be said here.
Small block plane, wood rasp, course sand paper.
Tried to use a power hand plane, it rips the end grain and splinters the side of the drum – I don't recommend it.
Sanding the top and bottom rims level . I have glued four sheets of 80 grit garnet paper to a piece of chipboard. Then it's just a matter of dragging the drum shell around in a circular motion, keeping the edge in contact with the sand paper at all times. It's hard on the arms but effective.
The bottom of the drum wants to be quite smooth, however the top does not have to be sanded until completely flat. We will soon be shaping the lip, which means taking a good radius off the outside lip, and a smaller radius off the inside lip. It is only the section in between that has to be flat all around the lip.
The next stage is to shape the lip. I came across a web page (apologies to the author – I don't recall where) that describes the profile of the lip a similar to your thumb viewed from the side, with your nail being the inside of the drum, and the curvature of the fleshy part being the outside.
To achieve this, I use the simple jig shown here, to mark concentric circles on the top edge of the drum. The innermost circle is just larger than the smallest radius of the inside corners. I shape a small radius to this line. The other circles act as guides for successive shaping of the larger radius on the outside of the rim.
The tool of choice here is the wood rasp.
There's usually a good deal of wood that needs to be taken out on the inside of the lip and a course rasp is pretty essential, preferably a half-round rasp.
You can see how I have already gone around the outside taking a slice out of the outside rim, to the outermost marked circle. I will take a lesser angle to the next marked cicle, and so on until the last surface before the innermost circle is flat. This will be the baring edge for the drum skin, and wants to be fairly thin to avoid the skin buzzing on the flat surface. Like your thumb, it should come to a gentle apex then fall off quickly to the inner edge of the rim.
You can see in this image how it is necessary to take a scollop out of the inside surfaces to shape the flat inside stave surface into a round rim shape.
And
here are the four drum shells, ready for finishing. From the left,
the djembe in Silky Oak, ashiko in Agathis, ashiko in Sheoak and my
little test shell in recycled pine pallets.