The Stanley 57 Core-box plane
The odd-looking plane is a woodworking tool you wouldn't find in the average woodworking shop. It came instead from an iron foundry, where it belonged to the craft of patternmaking.
Metal casting begins with a pattern—a replica of the item to be cast. The pattern, oversized to allow for shrinkage that occurs as molten metal cools, is used to make a mold. Once, foundry patterns were made largely, if not entirely, of wood. Patternmakers were all-around woodworkers, skilled at joinery, carving, and turning. (Many still are.)
The Stanley 57 core-box plane, served one patternmaking task—hewing a half-round channel for the top or bottom half of a core box. A core box is a form for making a core, a cylindrical element placed in a mold to create a hole in the casting. Cores form the cylinder bores in an engine block, for example.
A V makes half an O
A plane with a round-nosed iron and semi-cylindrical sole would carve core-box channels of a fixed size easily. But because a foundry mold might call for cores of any diameter, practicality demanded a tool that could hew out channels of different sizes. A plane with a pointed iron and a V-shaped sole provided the solution.
The beauty of the V-shape is that the plane automatically maintains the radius for a half-round groove of any diameter. (The groove's width equals the diameter of the core to be made in the form.) With the plane's wings riding along the edges of the groove, the iron, which extends through the point, always forms a perfect radius, as shown below.
The 7⁄8 "-wide, pointed blade (lying on the bottom of the plane, shown below) doesn't cut away the wood very quickly, however. So, the core-box grooves ordinarily would be roughed out with gouges or other tools first, and then completed with the plane.
The basic Stanley 57 with one wing extension installed on each side could handle work 1-5" in diameter. With two extensions in place, as shown in opening photo, it could go to 7-1⁄2 ", and with a full set of three, 10".
The 57's heyday came with American industrial growth, around the turn of the century. (The plane was marketed from 1896 until 1943.) From about 1909 until 1923, Stanley catalogued a smaller core-box plane, too. This one, the 56, covered a range from 9⁄16 -2". A 57 in good condition with a full set of three extensions might bring upwards of $400 from a collector today. A 56 could fetch even more.
And while you might not find a plane like this in what we think of as a woodworking shop today, you will likely find its descendant--the core-box router bit.
Photographs: John Hetherington Written by: Larry Johnston Tool from the collection of Philip W. Baker, Venice, Florida.