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Straightening a long timber edge is one of the jobs where a longer hand plane earns its keep. A short plane can remove bumps, but it tends to follow them. A long jointer plane bridges hollows and cuts only the high spots, leaving an edge that is straight enough for accurate joinery, a fence, a tabletop glue-up, or a clean reference face.
The best jointer plane is not simply the longest or most expensive one. It needs a sole that is reasonably flat, a blade that holds an edge, and enough mass to cut steadily without becoming exhausting. For most carpenters, a 22- to 24-inch plane is the useful middle ground. Very long planes are valuable on wide, heavy work, but they are slower to set up and tiring to use overhead or on a workbench that is too short.
What a jointer plane does
A jointer plane is used to make a surface flat, straight, or square to another surface. On a long edge, its sole spans dips in the timber while the blade trims the high areas. This is different from a smoothing plane, which is designed to leave a fine finish, and a jack plane, which is mainly a stock-removal tool.
Traditional jointer planes are often identified by numbers. A No. 7 is roughly 22 inches long and is a practical choice for general edge jointing. A No. 8 is commonly around 24 inches and has more weight and cutting length. A No. 6 is shorter, usually about 18 inches, and is easier to handle but less effective at correcting long, wandering edges.
For site carpentry, a good No. 7 jointer plane is usually the safest recommendation. It is long enough for most doors, worktops, framing timber, and furniture parts without feeling like a specialist tool.
Best types of jointer plane
| Type | Typical length | Best use | Main trade-off |
|---|---|---|---|
| No. 6 fore plane | 18 in / 457 mm | General work, shorter boards, lighter handling | Less effective over long hollows |
| No. 7 jointer plane | 22 in / 560 mm | Most edge jointing and medium-sized boards | Can feel heavy on narrow benches |
| No. 8 jointer plane | 24 in / 610 mm | Long, wide, or heavy timber | Higher cost and more effort to control |
| Wooden jointer plane | 24-30+ in / 610-760+ mm | Long boards and traditional work | More setup, less predictable condition when used |
Cast-iron planes are the easiest choice for buyers who want repeatable results. Their weight helps the plane stay on the timber, and replacement blades and parts are widely available. A well-made vintage plane can be excellent value, but expect to clean rust, check the sole, repair damaged threads, and flatten or replace the blade.
Wooden jointers are lighter than they look and can glide well on resinous timber. They are also often cheaper second-hand. The downside is that the sole and mouth may move with humidity, and the wedge must hold the iron securely. Buy one only if you are comfortable checking and adjusting wooden planes.
What to look for before buying
Check the sole with a reliable straightedge. It does not need to be polished flat over every square inch, but the area around the mouth should be sound, with no deep hollow or twist. Put the straightedge along the length, across the sole, and diagonally. A small hollow at the toe or heel is usually harmless; a twist that rocks the plane is not.
The blade should be wide enough for the plane and free from deep pitting near the cutting edge. Minor staining is acceptable. A badly pitted edge may never support a consistent, fine shaving. The cap iron should fit closely to the blade, and the adjustment mechanism should move without excessive backlash.
For rough straightening, a blade camber of about 0.5 to 1 mm is useful. It prevents the corners digging into the timber. For final edge jointing, use less camber—around 0.2 to 0.5 mm—so the plane can leave a nearly flat surface. A perfectly straight blade edge is not always better; exposed corners create tracks and make the plane harder to start.
Look for a comfortable tote and front knob, especially if you will joint hardwood or thick framing stock. A plane weighing roughly 3.5 to 4.5 kg gives useful momentum, but extra weight is not a substitute for a sharp blade. If your bench is short, a No. 6 fore plane may be the cheaper and more manageable option. It is fine for boards under about 1.5 metres, provided you check straightness with a separate straightedge.
How to joint a long timber edge
Support the timber firmly, with the edge slightly proud of the bench. If the board moves, the plane cannot produce a reliable result. Set the iron for a light cut at first—roughly 0.05 to 0.15 mm. Take diagonal strokes across the high areas, then switch to strokes along the length as the edge improves.
Keep pressure over the front of the plane at the start of the stroke. Transfer pressure toward the rear as the plane leaves the work. This prevents the common failure of rounding the ends. If the leading end is low, the plane will remove more material at the beginning; if the trailing end is low, it will remove more at the far end. Mark the edge with pencil lines so you can see where the blade is cutting.
Check progress with a straightedge and winding sticks. For a glue joint, a slight hollow of less than 1 mm over a 2-metre edge can be acceptable and may even close under clamps. A convex edge, a twist, or a hollow that exceeds several millimetres will cause gaps and make alignment difficult. Do not rely on the plane sole alone to prove the timber is straight.
When to spend more
Spend more on a premium plane if you need it to work immediately, use it every week, or want dependable adjustment and replacement parts. A well-tuned vintage Stanley-style plane can perform just as well, but only after inspection and sharpening. Search for a cast-iron No. 7 jointer plane when comparing new and refurbished options.
The cheaper option is fine when the plane is occasional backup equipment or the timber is short enough for a jack plane and straightedge. Avoid bargain planes with cracked castings, a loose frog, a warped sole, or a blade that cannot be adjusted evenly. Those faults turn a straightforward edge into a long repair project. For most buyers, a sound No. 7 with a properly sharpened iron is the best balance of reach, control, and cost.