Plane Building

Part of Woodworking

Without a plane, you cannot make a truly flat surface. Sawn boards are rough. Split wood has ridges. Only a plane can produce the smooth, precise surfaces needed for tight joints, furniture, and finish work. The good news: a functional wooden plane can be built with basic tools.

Why Planes Matter

Consider what you cannot do without a plane:

• Flat surfaces: A table top, door panel, or shelf that is truly flat requires planing. No amount of sanding by hand replaces what a plane does.
• Consistent thickness: Boards sawn from a log vary in thickness along their length. A plane brings them to uniform dimension.
• Tight joints: Two boards that must meet edge-to-edge (a tabletop, a door) need edges that are straight and square. A plane creates these edges. A saw cannot.
• Smooth finish: A planed surface is smoother than a sanded one. The plane slices the fibers cleanly; sandpaper tears them.

Anatomy of a Wooden Plane

Understanding each part is essential before you build one.

Part	Function
Body (stock)	The main block of wood. Your hands hold it, the sole rides on the workpiece.
Sole	The flat bottom surface of the body. Must be dead flat — this is the reference surface.
Throat (mouth)	The narrow opening in the sole through which the iron protrudes and shavings pass.
Bed	The angled surface inside the body on which the iron rests.
Iron (blade)	The cutting edge. A flat piece of steel, sharpened to a fine edge.
Chip breaker (cap iron)	A piece of metal clamped to the top of the iron, close to the edge. It curls the shaving and prevents tearout.
Wedge	A tapered piece of wood driven between the iron assembly and the abutments to hold everything in place.
Abutments	The angled surfaces on either side of the throat opening against which the wedge presses.
Escapement	The opening above the throat through which shavings exit the body.

    Side Cross-Section:

         ┌─────── Wedge
         │  ┌──── Chip breaker
         │  │ ┌── Iron (blade)
         ▼  ▼ ▼
    ╔═══════════════╗
    ║   /  /  /     ║ ← Escapement (shavings exit)
    ║  / // /       ║
    ║ / // /  BED   ║ ← 45° bed angle
    ║/ // /         ║
    ║ ▼▼            ║
    ╠═══╬═══════════╣ ← Sole (flat bottom)
         ↑
       Throat (narrow opening)

Choosing Wood for the Body

The body must be:

• Dense: It wears against the workpiece constantly. Soft wood wears out quickly and loses its flat sole.
• Stable: It must hold its shape despite humidity changes. A warping plane body means a warping sole — useless.
• Workable: You need to cut precise internal surfaces. Wood that tears out unpredictably makes this difficult.

Species	Rating	Notes
Beech	Best	Traditional plane wood worldwide. Dense, stable, wears well, available.
Hard maple	Excellent	Harder than beech, slightly more prone to movement.
Apple/pear	Excellent	Fruitwoods are dense, fine-grained, and stable. Often too small for large planes.
White oak	Good	Dense and available. Slightly coarser grain than ideal.
Hornbeam	Excellent	Extremely hard and stable. Preferred in continental Europe.
Lignum vitae	Superb (sole only)	Self-lubricating, incredibly dense. Traditional for the sole insert of high-wear planes.

Use Seasoned, Quartersawn Stock

The body blank must be thoroughly dry (6-8% MC) and ideally quartersawn (growth rings perpendicular to the sole). Quartersawn wood moves the least with humidity changes, keeping the sole flat over years of use.

Building the Body

Dimensions by Plane Type

Plane Type	Body Length	Body Width	Body Height	Purpose
Smoothing plane	7-9 inches	2.5-3 inches	2.5-3 inches	Final surface finish
Jack plane	14-16 inches	2.5-3 inches	3 inches	General purpose, removing material
Jointer plane	22-26 inches	2.5-3 inches	3-3.5 inches	Flattening and straightening edges

Step-by-Step Construction

1. Prepare the blank

Start with a block of beech (or your chosen species) at the final dimensions plus 1/2 inch in each direction. The block must be flat, square, and free of defects. If you do not have a single block large enough, laminate two pieces with a strong glue joint — but the sole must be a single piece or the joint will show and may open.

2. Mark the bed angle

The bed angle is the angle at which the iron rests against the body. This is measured from the sole (horizontal).

Bed Angle	Name	Use
45 degrees	Common pitch	General purpose. Works well on most straight-grained wood.
50 degrees	York pitch	Hardwoods with moderate figure. Reduces tearout.
55 degrees	Middle pitch	Difficult figured wood (curly, interlocked grain).
60 degrees	Half pitch	Very difficult grain. Requires more effort to push.

For your first plane, use 45 degrees. It is the most versatile and easiest to push.

Mark the bed angle on both sides of the body. The bed line starts at the throat location on the sole and angles up and back.

3. Cut the throat and bed

This is the most critical step. The throat must be narrow, the bed must be flat, and the abutments must be symmetric.

Method 1 — Split body (easiest for beginners):

• Saw the body block in half at the throat/bed angle
• Shape the internal surfaces (bed, abutments, escapement) while the two halves are accessible
• Glue the halves back together

Method 2 — Mortise from above:

• Chop a mortise from the top of the body down to the sole
• Shape the bed and abutments with chisels
• Requires more skill but produces a stronger body

For the split-body method:

1. Saw the block along the bed angle line, starting from the top
2. On the front piece: shape the front face of the escapement. This face angles forward from the throat to create room for shavings to curl up and out.
3. On the rear piece: flatten the bed surface. This MUST be dead flat — the iron rests on it. Check with a straightedge. Any hollow or bump prevents the iron from sitting solidly.
4. Shape the abutments: On each side of the throat opening (inside both halves), cut small angled ledges. The wedge presses against these to hold the iron.
5. Glue the halves back together. Align the sole surfaces perfectly. Clamp firmly and let cure completely.

4. Open the throat

After gluing, the throat may be too tight or completely closed. Open it from the sole side using a narrow chisel:

• Target throat width: 1/16 inch (1.5 mm) for a smoothing plane. Up to 1/8 inch (3 mm) for a jack plane.
• Narrower throat = finer shavings, less tearout, but clogs more easily
• Wider throat = thicker shavings, faster material removal, more tearout risk
• You can always widen the throat later. You cannot narrow it. Start narrow.

Throat Width Is Critical

A throat wider than necessary is the most common mistake in plane building. It allows the shaving to dive down in front of the iron instead of curling up, causing tearout. A tight throat supports the wood fibers right up to the cutting edge. Start at 1/16 inch and widen only if shavings jam.

5. Shape the exterior

• Round the edges and corners for comfort — your hands grip this tool for hours
• Shape the front (horn/tote) and rear grip areas to fit your hands
• The sole remains flat and sharp-edged at the sides (this lets you plane into corners)

Making the Wedge

The wedge holds the iron (and chip breaker) against the bed.

1. Material: Same species as the body, or harder. Grain must run the length of the wedge.
2. Taper: About 10 degrees. The wide end faces up, the narrow end goes down toward the iron.
3. Width: Slightly narrower than the throat opening, so it can be inserted and removed easily.
4. Fitting: The wedge must bear evenly on both abutments. If it only contacts one side, it will push the iron sideways. Adjust by planing the wedge or the abutments until pressure is even.

To lock the iron: place the iron on the bed, set the chip breaker on top, slide the wedge in above both, and tap it with a mallet until firm. To release: tap the back of the body (the “strike button” area) or tap the top of the wedge sideways.

The Iron (Blade)

If you are forging your own iron, the requirements are:

• Steel: High-carbon steel (old saw blades, files, leaf springs work). Must be hardenable.
• Dimensions: Width matches the throat width minus 1/16 inch on each side. Length sufficient to extend through the throat and up to the wedge area (typically 6-8 inches).
• Thickness: 1/8 inch (3 mm) minimum. Thicker irons chatter less.
• Hardening: Heat to cherry red, quench in oil, temper at straw/light blue (350-450 degrees F).
• Sharpening: Flat back, 25-degree primary bevel, honed to a mirror edge on the bevel and 1/2 inch of the back.

If you are repurposing: old plane irons, thick chisels, or even a piece of bandsaw blade can be ground to shape.

Fitting the Chip Breaker

The chip breaker (cap iron) clamps onto the flat back of the iron, close to the cutting edge. Its job:

• Curls the shaving: The angled chip breaker surface deflects the shaving upward so it curls and breaks instead of running ahead and tearing out grain.
• Stiffens the iron: Reduces chatter (vibration) during cutting.

Setting Distance

The distance between the chip breaker edge and the iron cutting edge controls performance:

Distance	Effect
1/64 inch (0.4 mm)	Maximum tearout prevention. For final smoothing of difficult grain.
1/32 inch (0.8 mm)	General smoothing. Good balance of performance and ease.
1/16 inch (1.5 mm)	Rough work. Faster shaving removal.

The chip breaker must seat perfectly flat against the iron back. Any gap lets shavings jam between them, stopping the plane instantly. File or stone the chip breaker’s mating surface until no light passes between it and the iron.

Adjusting Depth and Lateral Position

Depth

• Deeper: Tap the top of the iron with a small hammer. The iron advances through the throat, taking a thicker shaving.
• Shallower: Tap the back of the plane body (the strike button). The body shifts forward relative to the iron, reducing depth. On some designs, tap the top of the wedge to release slightly, adjust, re-tighten.
• Test: Hold the plane sole-up at eye level and sight along it. You should see the iron edge as a thin dark line just barely protruding above the sole surface.

Lateral Adjustment

The iron must protrude equally across the full width of the throat. If one side is deeper:

• Tap the side of the iron (at the top) lightly with a hammer to shift it sideways
• Re-tighten the wedge
• Sight along the sole again to verify

Truing the Sole

The sole must be flat. Not “pretty flat” — dead flat. This is the reference surface that controls everything the plane does.

1. Find a known flat surface: a piece of plate glass, a machine table, or a flat stone slab
2. Place sandpaper (80-grit to start, then 150-grit) on the flat surface
3. Rub the plane sole on the sandpaper with even, full-length strokes
4. Check progress by marking the sole with pencil lines across the width. Where the pencil marks disappear, the sole is touching. Where they remain, the sole is low.
5. Continue until all pencil marks disappear simultaneously
6. Finish with 220-grit for a smooth sole surface

True the Sole Under Tension

When truing the sole, have the iron and wedge installed and lightly tightened (but retracted so the iron does not contact the sandpaper). The wedge pressure slightly distorts the body. Truing under this pressure means the sole is flat when the plane is actually in use.

Using the Plane

Basic Technique

1. Place the workpiece on a flat surface and secure it (workbench with stops, or clamp)
2. Set the iron for a thin shaving — you should barely see it protruding from the sole
3. Place the plane on the workpiece, tipped slightly forward
4. Push forward with steady, even pressure. Transfer weight from front to back as the plane travels: press down on the front at the start of the stroke, even pressure in the middle, press down on the back at the end. This prevents rounding the edges of the workpiece.
5. Lift on the return stroke — dragging back dulls the iron

With the Grain

Always plane in the direction that the grain slopes away from the surface (like petting a cat from head to tail). Planing against the grain catches the fibers and tears them out, leaving a rough surface.

If you get tearout: reverse direction. If both directions tear: increase the bed angle (use your higher-pitched plane), close the throat, set the chip breaker closer to the edge, or take a thinner shaving.

Skewing the Plane

Angling the plane 15-30 degrees to the direction of travel effectively reduces the cutting angle. This makes the plane cut more easily, especially in hardwoods. It also produces a slicing cut that leaves a smoother surface.

Plane Types and When to Use Each

Type	Length	Job	Analogy
Jack plane	14-16 inches	First pass. Removes bulk material and major unevenness. Set for a thick shaving.	Roughing in
Jointer plane	22-26 inches	Second pass. The long sole bridges hollows and rides over bumps, gradually cutting the high spots until the surface is flat and straight.	Leveling
Smoothing plane	7-9 inches	Final pass. Set for the thinnest possible shaving. Leaves a glass-smooth surface ready for finish.	Polishing

If you can only build one plane, build a jack plane. It handles the widest range of tasks. The smoothing plane is the second priority — it makes the final surface. The jointer is essential only when you need long, straight edges (tabletops, door edges).

Sole Profiles

• Jack plane: Sole can have a very slight crown (convex) across the width. This prevents the corners from digging in during heavy stock removal.
• Jointer plane: Sole must be dead flat in all directions. Any deviation transfers to the workpiece.
• Smoothing plane: Sole must be dead flat. The iron may have a very slight camber (curved edge) to blend overlapping passes and prevent plane tracks.

Plane Building — At a Glance

• Without a plane, you cannot make truly flat surfaces or tight joints
• Body: dense, stable wood (beech, maple). Quartersawn, fully seasoned.
• Bed angle: 45 degrees for general work, higher for difficult grain
• Throat: start narrow (1/16 inch), widen only if shavings jam
• Wedge: 10-degree taper, must press evenly on both abutments
• Iron: high-carbon steel, flat back, 25-degree bevel, razor sharp
• Chip breaker: set 1/32 inch from the cutting edge for smoothing; must seat perfectly flat
• True the sole dead flat on a known flat surface with the iron and wedge installed
• Plane with the grain, skew for easier cuts, transfer pressure front-to-back through the stroke
• Build a jack plane first, smoothing plane second, jointer third