Most wooden scrub planes follow a very simple design. Some have horn-style front handles based on an old European design. The “rear handle” is simply the rear of the stock, or body.
The design of wooden scrub planes varies considerably in respect of the handles and the shape of the stock.
However, the usual method of securing the blade (with a wooden wedge) and adjusting the blade (with a hammer or mallet) means there are generally no screws or mechanisms to consider.
This is the major part of the plane to which everything else is attached. It is made from hardwood, which might be ash, beech, oak, hornbeam, maple or mahogany.
The sole is the part that slides over the surface of the workpiece as it is being planed. It needs to be perfectly flat. It is usually formed from the same piece of wood as the body, but in some cases a separate piece of wood that is even harder than the body is used to give extra protection against damage.
As with the metal versions of the scrub plane, the iron is deeply cambered, or rounded, so that the blade acts as a gouge to remove lots of excess wood. The iron is bedded on an internal sloping part of the stock, usually at 45 degrees to the sole.
Wedge and wedge stops/clamp bar
The wedge’s job is to hold the iron firmly in place. It usually sits behind a pair of stops cut into the the stock.
However, on some scrub planes, the wedge is fitted behind a wooden or metal clamp bar. Hammering the wedge downwards, behind the stops or clamp bar, increases pressure between the wedge and the iron, holding the iron firmly in place.
Scrub planes have wider mouths than most other planes to allow thick shavings of wood through. As the scrub plane’s primary purpose is the removal of unwanted width or depth of wood as quickly as possible, a wide mouth is essential.
The wedge-shaped space above the mouth is often referred to as the throat, but some experts argue that this is not really a part, just a convenient space for the shavings to go through.
The front handles of wooden scrub planes, where fitted, vary greatly in their design, usually depending on where the plane was made. On some, particularly European ones, they are horn-shaped. On others, they may be fairly straightforward knobs.
Wooden scrub planes also vary in the kind of main handle provided. Sometimes the ‘handle’ is simply the rear end of the stock. Some have closed handles like those found on traditional woodworking saws.
They may also have pistol grip handles.
But there are exceptions . . .
While nearly all wooden scrub planes follow the basic design outlined above, there are exceptions. One is that some scrub planes DO have lever caps with knobs.
There are also wooden scrub planes with metal mechanisms for adjusting the depth and lateral angle of the iron. This makes adjusting the iron easier, but doesn’t affect the performance of the plane.