Buying a Jointer: The Tool Everyone Skips and Regrets

A jointer's job is unglamorous and essential: it flattens one face of a board and squares one edge to it, giving you the two flat reference surfaces every other machine in the shop assumes you already have. It's also the tool most new shops skip to save money, and the one that causes the most confusion downstream when boards won't sit flat or glue up cleanly.

Why you can't just skip it (and use a planer instead)

A thickness planer makes a board a consistent thickness relative to whatever face is already riding on its bed. If that face is cupped, twisted, or bowed, the planer reproduces the same problem on the opposite face at a thinner thickness — it does not flatten anything. A jointer is what actually establishes flat.

Bed length matters more than most specs

Jointer bed length (the infeed and outfeed tables combined) determines the longest board you can reliably flatten. A short-bed jointer will happily follow a board's curve instead of flattening it out, especially past about 4 feet. If you build furniture with long components — table legs, rails, door stiles — bed length is worth prioritizing over width.

Cutterhead type, same tradeoff as planers

• Straight knives cut cleanly on cooperative, straight grain and cost less to buy and maintain.
• Helical/spiral cutterheads (many small indexable carbide inserts) handle figured and reversing grain much better, run quieter, and shrug off the occasional embedded staple that would nick a straight knife — at a real price premium.

Width capacity: buy for your widest common board, not your widest board ever

A 6" jointer covers the vast majority of furniture parts. Wider jointers (8"+) cost meaningfully more and take up more floor space; they matter if you regularly face-joint wide panel stock, but for edge-jointing and typical furniture components, 6" is the practical sweet spot for most home shops.

The two things people get wrong

First, skipping the jointer and trying to flatten with a planer alone, as covered above. Second, buying based on width capacity without checking bed length — a wide, short-bed jointer is a worse practical purchase for furniture work than a narrower, longer one.