Wednesday, April 27, 2011
Toothing Planes and Glue Pots
I started the American School of French Marquetry to introduce woodworkers (who were not fortunate enough to have been born in France) to a tool that is amazing: the chevalet de marqueterie. Unfortunately, the British translated the name to "donkey" and the aversion to the tool has persisted for centuries. I say, unfortunately, since I think the chevalet is the neatest tool since the one made to slice bread.
In my 40+ years of collecting woodworking tools (that do not require electricity), I think I have read most of the books and visited many of the sales and collections, so that I can usually recognize what a tool is designed to do. Sometimes I find a special purpose plane or tool which becomes the subject of speculation, as it might not be obvious to the first glance what it does. One of the fun pastimes for tool collectors is to share such tools among themselves to create intelligent speculation and form opinions, often not even close to the actual truth.
This has been going on for years.
One of my favorite books is the 50th anniversary publication of "The Chronicle of the Early American Industries Association", volumes 12-26, March, 1959 to December, 1973. It is nearly 1000 pages in one book which comprises all the newsletters of EAIA during those years. It is very interesting to read the questions raised and follow the responses during the following issues, as members add to the collective knowledge of some obscure aspect of the trades.
I noticed early in reading this book a question about a toothing plane. Something like "what is the purpose?" As I followed the train of thought through pages and pages of information, it became clear to me that the toothing plane was a common tool that had lost its importance in the trade by the middle of the 20th century. So I immediately started collecting toothing planes.
I found out a lot about the tool, some of which I discovered through research, some from European masters and some from direct experience. One of the first things I was told was the toothing plane proved the "truth" of the work. By that I mean that when you hand surface wood, and then veneer it, you need to know it is flat. Any imperfections created by hand planing will be transmitted through the veneer, as the hot glue cures and pulls down the veneer tightly onto the surface. By running the toothing plane at an angle to the grain, first in one direction and then in the opposite direction, you create a cross hatching of tooth marks which will not appear on any slight depression. Therefore, an even pattern of tooth marks on the entire surface proves it is flat, or the "truth" of your work.
In researching early veneer methods in France, I learned that before 1800 all veneer was sawn by hand from logs. This process left rather rough saw marks on the veneer and the material was obviously thick, about 3-4mm. Such veneer would be hard to bend onto the shapes of the furniture made during the Baroque and Rococo periods. Therefore, a toothing plane was developed, with rather fine teeth, to work the veneer, removing the saw marks and making the veneer thinner without creating tearout. The toothing plane has a steep angle to the blade, between 85-100 degrees, like a scraper.
Another plane with much larger teeth was made for the carcase. Usually the carcase was made of oak or beech and hand surfaced, so it needed to be toothed to guarantee a flat surface.
After 1800 the French created a mechanical saw which made veneer much neater, usually 1.2-2mm in thickness, and with regular saw marks. Therefore the toothing plane with the fine teeth was no longer necessary, but the other plane remained in the shop for the carcase. As steam power became popular, slicing veneer machinery replaced the saw (except in France) and the use of power tools in general made toothing unnecessary. However, in traditional workshops where hot glue was used, evidence of toothing plane marks remained until the middle 20th century.
The survival of the toothing plane is due to other reasons it was used. It creates a larger glue surface area. It reduces the chance of glue starvation when the joint is under pressure. It removes dirt, old glue, and oxidation, creating a fresh wood surface. It is essential in applying rubbed glue joints and hammer veneering. Most importantly, when the surface is hand planed, it proves the ""truth" of the work.
The first tool I made when I started my career was a toothing plane, shown in the left of the photo. Note the variation in the tooth spacing on the irons, which range from an 18th century iron on the left to a 20th century iron on the right.
More on glue pots tomorrow. I'll also talk about how to sharpen toothing plane irons.