If you line up the collection of MTC hand planes on the bench — from the short block plane through to our full-length jointer — the differences in length can seem almost arbitrary. After all, they all do the same thing, right? They shave wood.
In reality, the length of a hand plane is one of its most important design features, and it directly determines what problem that plane is meant to solve. Plane length governs how the tool references the surface beneath it — which means it controls whether the plane follows the timber’s imperfections or corrects them.
Understanding this makes choosing (and using) the right plane far simpler.
The Core Idea: Reference Length
A hand plane rides along the surface of the wood as it cuts.
The sole of the plane acts as a straightedge. As the plane moves forward, the toe and heel rest on the surface, bridging over highs and lows. The longer the sole, the more of the surface it references at once.
Short planes reference a short section of the wood, and so will ride down into hollows.
Long planes reference a long section of the wood, and so the blade will be left hanging over hollows, cutting only the high spots. This brings the surface closer and closer to ‘true’ with each pass.
That single principle explains almost everything about plane length.
Long Planes: Enforcing Straightness
Longer planes — like the jointer and jack — are prevented from following short bumps or dips in the timber by their length. The blade won’t be able to reach the low spots, so with each pass the timber will become closer to flat: perfect for flattening a table top or jointing an edge.
Short Planes: Following the Timber
Short planes — such as the block plane, smoothing plane and the cabinet scraper— have relatively little sole in contact with the work, so they won’t increase the flatness as much as a longer plane. However this can provide a better surface finish, as the plane takes long, continuous shavings across the whole piece.
Of course, there are some caveats and work-arounds.
If there are no dips (because your board is shaped like one continuous hill) then no plane will help you. The toe and heel of the plane will be hanging in the air no matter how long it is, and you will simply keep following the ‘hill’ with each pass. The solution is fairly simple – take some short passes in the middle of the board to create a low spot deliberately (see our article on: A Beginners Guide to Edge Jointing)
And if you’re using a plane that’s a little shorter than ideal, check the surface with a straight edge to find the highest high spots and work on them first – with frequent checking you can still flatten a board successfully while you fill your tool cabinet.
Hand planes aren’t different lengths by accident or fashion. They’re different lengths because wood isn’t flat, straight, or predictable, and no single reference surface can handle every task.
Once you understand that plane length controls how a tool relates to the timber beneath it, choosing the right plane becomes intuitive — and using it becomes far more effective.