What Is An Infill Plane?

If you’ve ever had the opportunity to search through the internet or flicked through a woodworking book or magazine you’ve probably noticed that there are many, many different types of woodworking hand planes, all in various shapes, styles and sizes. Construction-wise, some are made mostly from wood, while others are made from metal. There are even some modern woodworking planes whose main body construction is made of plastic, but just what is it that makes and infill plane an infill plane?

As a whole, all true infill planes have a core of wood which in encased in a channel of iron, steel, brass or bronze. This form of construction became popular around the early 1800’s, however the idea of a metal plane with a wooden core goes back at least 2000 years to the time of the Roman Empire. In fact ancient infill planes were discovered at Pompeii during the excavation of that city back in 1926. The style of these ancient planes mostly resembled the later Dutch wooden planes from the 1700’s, but were definitely infill planes made from iron and wood rather than just the wood itself.

In the late 1700’s and early 1800’s this method of construction was primarily used for high-end mitre planes in Britain, where plates of iron would be joined by dovetails to form a “box” in which the timber would be seated by means of screws or pins that would go through from side to side, locking the wood in place. Mitre, or miter, planes relied on a very low cutting angle so that the plane blade could “shear” the end-grain fibers of the timber. Having such a low angle creates a very thin “wedge” section of the planes’ sole (bottom) can be a weak spot in a traditional wooden plane, so having the sole and sides of a plane made from metal can eliminate that problem. With industrial iron casting still relatively in its infancy at that time it made sense to construct a plane from plates and could be done, with varying results, by the craftsman or woodworker himself. It was still a costly exercise though — after all good wrought iron was hard to find.

Because they were considered as high end tools, many of the early mitre infills used the quality cabinet timbers of the time, primarily walnut or Cuban mahogany. Before too long Brazilian rosewood became popular as the preferred infill wood, along with ebony or African blackwood and, occasionally (and if it was available in suitable sizes), English boxwood. However later planes in the 20th century, between the two World Wars where obtaining suitable quantities of exotic timbers was becoming increasingly difficult, used beech which was then given a dark stain to simulate a more expensive timber.

While early infill mitre planes often had dovetailed soles and sides, the foundries in Britain were beginning to produce better and more reliable castings. Before too long there were some foundries scattered throughout England and Scotland offering raw mitre plane castings for tradesmen to complete themselves. This proved a boon for a young Scottish cabinetmaker named Stewart Spiers who, on a trip to Edinburgh when he was 21, procured a casting from a foundry which he took back to his home town of Ayr to complete. He was so impressed with the finished item that he decided to obtain more castings and complete them in the same manner. Spiers contemporaries were also impressed with his work and before long were lining up and buying the finished planes as soon as he completed them. However, traveling from Ayr to Edinburgh or Glasgow — the two largest cities in the region — was quite an undertaking in those days. There had to be a better way. A way to make planes at any time, without the need to go to one of the larger industrial cities for castings. What followed was one of the biggest success stories in planemaking and set the standard for the “classic” infill plane which we know today. It helped to herald a golden age of woodworking tools and put Stewart Spiers at the pinnacle of plane makers all around the world.

It’s safe to say that, apart from the early Roman planes, there were very few infill bench planes manufactured before Stewart Spiers decided to make them. As mentioned earlier there were only mitre planes in this style that were produced in any great number. Stewart Spiers became the inventor and innovator of a wide range of infill bench planes whose designs were copied by dozens of manufacturers and thousands of individual makers around the world.