Thoughts on Scrub Planes

I’m often asked about scrub planes, and why I don’t typically use them. The short answer is that I don’t often find them necessary in what I do because of the way that I work. With the method of working that I subscribe to, which I will discuss here in a moment, scrub planes rarely enter the picture.

As with many things in woodworking, if one were to ask a dozen woodworkers how to flatten the face of a rough sawn board using only hand tools, it’s very likely that they would receive a dozen different answers. There are almost as many opinions on how to perform this seemingly simple task as there are different types of hand planes for doing it. Of course none of the various methods are wrong, as long as they are performed safely and result in a board with a flat face. However, the method of surfacing lumber that I have settled on over the years does not usually involve a scrub plane.

The first scrub plane I ever owned was purchased when I was first starting to learn to use hand tools over 20 years ago. I bought it, because I had seen a video on preparing rough sawn lumber with hand planes, and in that video that’s what the instructor used. Starting with the scrub plane was the common approach generally recommended on the internet as well, and the internet is always right, therefore, I thought the scrub plane was necessary.

So, I went out and bought myself a metal scrub plane, sharpened it up and went to work on a piece of rough sawn lumber. When I finished “scrubbing” the face of the board, I was horrified at what I saw. The board had deep, narrow troughs and gouges all across it, and it certainly was no closer to being flat than when I started.

Nonetheless, I forged on, switching to my handy #5 jack plane. I used the jack plane across and diagonal to the grain and the board began to look better. Soon, I had removed all the deep troughs left by the scrub plane and replaced them with shallow waves from the slightly cambered iron of the jack plane.

Feeling more confident, I moved on to the try plane, planing diagonal to the grain and then with the grain, finally bringing the board face flat. I was so proud of myself that I flipped the board over and went at the other side with the scrub plane, and repeated the whole process until that face was flat. When I was finished, I was sweaty, but proud that I had dressed a rough sawn board. Unfortunately, I had taken a 4/4 board and turned it into a board that was just over 1/2″ thick! This experience made me seek out more information on the process. Soon after, I sold that first scrub plane, and vowed that I wouldn’t ever use one again.

Of course the problem wasn’t with the scrub plane. The problem was the way I was using the tool. I had been trying to use the plane to flatten the first face of the board by planing the entire face, and this is really not what the scrub plane was designed to do. The result was that I had removed a lot of wood from areas of the board that I shouldn’t have.

The short length of the scrub plane simply followed the existing contours of the board, and created deep hollows in the board’s face. Therefore, I had to remove a lot of additional material with the jack plane to begin to flatten the board’s face. This of course resulted in a much thinner board and a lot of unnecessary additional work.

As I began to explore traditional woodworking more and more, my research on the historical practices of the craft led me to old English texts, such as The Academy of Armory by Randle Holme (1688), Mechanik Exercises by Joseph Moxon (1703), and The Mechanic’s Companion by Peter Nicholson (1831). Interestingly, while all of these books speak to the tools and process used to dress rough sawn lumber with hand planes, none of them mentions any tool resembling a scrub plane. It turns out that in the traditional English and American method of woodworking, the scrub plane simply didn’t exist.

Instead, in the English tradition, the first plane used in the process of facing stock was called the fore plane (called the jack plane in Nicholson’s text). According to Moxon,

“It is called the Fore Plane becauſe it is uſed before you come to work either with the Smooth Plane, or with the Joynter.”

In the English tradition, the use of the fore plane avoids the problems that I experienced using the scrub plane. The fore plane is traditionally 15″ to 18″ long, allowing it to ride over the low spots and only cut the high spots. Using the fore plane requires much less frequent checking with a straight edge compared to the short soled scrub plane, which can dip into hollow areas and make them even more hollow. Using the fore plane, one simply needs to ensure that the face has no wind (twist) with a pair of winding sticks, and perhaps check a time or two for flatness along the length and across the width and diagonals. There’s no need to constantly check for high spots with this method.

Additionally, with a moderately cambered iron, the fore plane leaves much shallower troughs than the scrub plane, which are easily removed with a few passes of the try plane. The fore plane’s length is one of its most important assets, and it’s secret to quickly bringing the face of a board to relative flatness.

There are a lot of theories about the intended use of the scrub plane. The Stanley No. 40 was not marketed as a joiner’s or furniture maker’s tool. In their 1914 catalog, Stanley had this to say about their scrub plane:

“With these planes the user can quickly plane down to a rough dimension any board that is too wide to conveniently rip with a hand saw, an operation that is sometimes called “hogging”. This is made possible by reason of the peculiar shape of the extra heavy cutter, the cutting edge of which is rounded instead of square.”

Based on Stanley’s description of the tool, it is unlikely that it was being marketed to furniture makers. The Stanley No. 40, wasn’t introduced into production until about 1896. This was long after the invention of the other iron bench planes, and long after professional joiners and furniture makers started using machines to process rough sawn lumber.

But Stanley didn’t invent the tool. It is possible that the Stanley version of the tool may have been modeled after an older continental European plane (called a schrupphobel in Germany, which roughly translates to rough plane). Unfortunately, I can’t speak or read much German, so I haven’t been able to come up with any historical information on the continental European version of this tool.

However, one theory that I’ve read is that pre-industrial continental Europeans may have had less access to sawn lumber and may have relied more heavily on riven material. I don’t have any documented evidence that this was the case, but riven material tends to start off much less close to flat compared to sawn boards, which would make a plane like a scrub plane much more useful to start with. Riven boards also tend to be shorter in general than sawn boards, again, making a shorter plane more effective. In my own limited use of riven material, I have in fact found that the scrub plane can be quite useful in this kind of work.

Regardless of the scrub plane’s origins, my own experiments with the tool have led me to the conclusion that it’s not the best tool for the initial flattening of the first face of a sawn board. Instead, I’ll typically flatten the first face of a sawn board with my fore plane and try plane, removing as little material as possible. After flattening the first face, if I need to remove a lot of thickness from the board, then I’ll break out the scrub plane. While the scrub plane won’t make the second face flat, it can remove a lot of material in a hurry – up to 1/8″ per pass in some woods. On the second face I’m usually working to a gauge line, so it’s easier to judge where material needs to be removed, and not do more harm than good. But, unless I have to remove a lot of thickness, the scrub plane just waits patiently in the till.

So I encourage you to experiment for yourself and see if a scrub plane fits in with your working habits. You may find that you hate the scrub plane and you may find that you love it. Ultimately, the scrub plane is just another arrow in the quiver.