Back when I used metal bench planes, like a lot of folks who like old tools, I had a good assortment of bench planes. I had pretty much all of the numbers in the Stanley catalog from #3 up to #7. This gave me a good choice in plane sizes for different tasks, however, I always seemed to gravitate toward the same three planes. I used the #5 for my initial work (i.e. as a fore plane) on rough sawn boards, then I flattened those boards with the #7. After completing all the joinery and test fits, I’d do my final smoothing with the #3. Even though I had a #4 (with a Hock iron and Clifton two piece chipbreaker) and a #4½, I still always reached for the #3 with it’s thin, narrow, stock iron for my smoothing needs.
When I switched over to wooden planes, I kept in mind the metal bench planes I tended to reach for the most, and chose woodies based on those planes. For the most part this worked out well. I use a 17″ wooden fore plane and a 22″ wooden try plane. My smoother is about the length of a #3 iron plane, but it’s iron is much wider than an equivalent #3, being closer in width to a #4½. I thought at the time this would be ideal, allowing me to smooth wider areas faster, but this has not proved to be the case.
To understand the difficulty, let’s examine the purpose of a smooth plane. When lumber is prepared from rough sawn to finish ready by hand, the common progression of bench planes is typically stated as fore plane (so called because it is used before the other planes) to try plane (used for trying or truing the surface, i.e. making it flat) to smooth plane (for removing any remaining surface imperfections). The longer the plane, the flatter the surface becomes. In an ideal world, all of our lumber would have straight, well behaved grain, and our try plane would get the boards perfectly flat. This would leave a surface ready to be finished after the try plane. However, anyone who works lumber completely by hand knows this to be the exception rather than the rule.
Instead, most lumber will have high and low spots, even after working with the try plane, and reversing grain that makes attacking a board from a single direction difficult at best. This is where the smooth plane shines. Because of its shorter length, it’s easy to reverse directions and spot plane small areas to take care of patches of tearout. However, the longer and wider the smooth plane, the more difficult this becomes.
Like any other plane, the longer and wider a smooth plane’s body is, the flatter it tends to make the surface. This all seems fine, until you try to spot plane a small low spot with tearout. In order to attack the area, you need to blend the surrounding area into the spot with the tearout. With a long, wide smoother, the blended area needs to be bigger in order to hit the low spot. However, with a smaller smoother, it becomes much easier to spot plane small areas. Shorter, narrower smoothers can tackle isolated areas of reversing grain like nobody’s business. This is why historically, smooth planes were shorter than the more common lengths we see preferred today.
Nowadays, most lumber is prepared with machines. Smooth planes are only used for final surfacing before applying finish. The machines are typically going to make lumber flat to a higher degree than what most of us using hand planes for preparing rough lumber are doing. So longer and wider smooth planes can work the boards sufficiently most of the time. When we plane lumber by hand, our boards typically aren’t as flat as machined boards. That’s not to say that hand planes aren’t capable of the same degree of flatness that machines are, just that we don’t need it most of the time, so we don’t bother taking boards to that level of flatness with planes. In this case, smaller smoothers are a blessing.
That’s why I always seemed to reach for my old #3. It’s shorter length and narrower width made it a more effective weapon against the dreaded tearout than my larger smoothers. It’s also the reason I seem to reach for my small wooden smoother more often than my larger one. The little guy is only 6½” long, with a 1¾” wide iron. It’s actually closer in size to a modern block plane than a typical modern smooth plane, however, it is bedded at about 55 degrees, perfectly pitched for smoothing domestic hardwoods. The larger and wider smoother does have it’s place, but if I could have only one smooth plane, I’d definitely choose the smaller plane over the larger one.