Chisel Types, Compared

Chisel catalogs list a dozen types and imply you need a representative sample. You do not. Most woodworking is done with one family, and the others exist for jobs you either do not do or that a machine does for you. Here is what each family physically is, and what happens when you use the wrong one.

Bench chisels — buy these

Bevel-edged, moderate blade length, handles designed to be struck with a mallet. They pare, they chop, they clean up joints, and they are what people mean when they say “chisels”. A four-piece set covers the overwhelming majority of furniture work.

The beveled sides are the important feature: they let the chisel get into an acute corner — the socket of a dovetail — without the square shoulder of the blade bruising the pin beside it. How thin those side lands are is a genuine quality differentiator.

Mortise chisels — only if you chop mortises

Thick, square in section, often with an oval hooped handle, and dramatically stiffer than a bench chisel. The section thickness is the whole point: a mortise is chopped by driving the chisel in and then levering the waste out, and that levering is what a bench chisel will not survive.

A bench chisel used to lever mortise waste does not bend. It snaps, usually where the blade meets the tang, usually without warning. This is the single most common way people break a chisel.

If you cut mortises by hand you want two or three sizes matched to your tenon thicknesses. If you cut them with a router or a drill press and clean up by hand, you need none, and a bench chisel does the cleanup safely because there is no levering involved. The best mortise chisels ranks the ones worth owning and gives the published hardness figures for each.

Paring chisels — useful, rarely essential

Long, thin, flexible blades with long handles, designed for two-handed pushing and never to be struck. The length gives control and lets the blade reach into places a bench chisel cannot; the thinness lets it follow a surface.

Hitting a paring chisel with a mallet damages it, and that is easy to do by reflex. They are a genuine pleasure for fitting work and they are the third or fourth purchase, not the first. The Japanese long-handled sets are the accessible version. The straight head-to-head, with published lengths and hardness figures for both families and which widths are worth buying, is on paring chisel versus bench chisel.

Firmer chisels — probably not

Square-sided rather than bevel-edged, and stronger for it. General carpentry and timber framing, where strength matters more than access. For furniture work the square shoulder is exactly the wrong feature, because it prevents the one thing bevel edges exist for.

The name is worth unpicking, because it causes more confusion than the tool does. A firmer chisel is not a heavier bench chisel and it is not a light mortise chisel. It is defined by one thing: the sides of the blade are left square instead of being ground away into bevels. That gives a stronger blade with more steel in the same width, at the cost of a shoulder that fouls anything with an acute internal corner. It will chop a hinge gain or clean a timber-frame housing all day; it will bruise the pin the moment you put it in a dovetail socket. The full breakdown is on what is a firmer chisel.

The reason it survives in catalogs is that most of the world's chisels are not sold to furniture makers. Site carpentry, formwork and timber framing all favor strength over access, and a square-sided blade is cheaper to make because grinding the lands is a separate operation. When a very cheap “bevel edge” set arrives with lands so thick they are barely bevels, that is the same economics showing through, and it is one of the specific things you give up on the best budget chisel sets.

The four families, side by side

Section, handle and intended abuse are the three things that actually separate the families. Everything else — steel, price, country of origin — varies inside each family rather than between them.

Where the families overlap, and where they genuinely do not

Most of the practical confusion comes from assuming the boundaries are sharper than they are. Three of the four overlaps are real, and one is not.

Bench chisels do most paring work. This overlap is large. A sharp bench chisel pares dovetail cheeks, hinge mortises and small shoulders perfectly well, and the honest reason people find their paring disappointing is usually a dull edge rather than a short blade.

Bench chisels do mortise cleanup. Also real, with one condition: chop and pare, never lever. If the waste is drilled or routed out first, a bench chisel squares the walls safely because nothing is prying against them.

Firmer chisels do bench work badly but do it. Real, and unpleasant. You can build furniture with square-sided chisels; you simply cannot clean an acute corner, so dovetails come out bruised.

Bench chisels do not lever mortises. This is the one boundary with nothing on the other side of it. It is not a matter of technique or of buying a better bench chisel: a thin blade with beveled lands has a small cross-section at the neck, and levering loads it in exactly the direction it has least material. The side-by-side is on bench chisels versus mortise chisels.

What the widths mean across the families

Widths behave differently in each family and this trips people up when they buy a second type. A bench chisel width is a preference — a 3/4 in chisel will clean a 1/2 in shoulder perfectly happily. A mortise chisel width is a specification: the chisel defines the joint, so a 10 mm chisel cuts a 10 mm mortise and nothing else, which is why mortise chisels are bought in ones and twos rather than in sets. A paring chisel width is about registration — wider blades reference off a surface better and overhang harmlessly, so you want fewer and wider rather than a full ladder.

The upshot is that a “set” is the right purchase in exactly one family. In the others, buy the width the job needs. Chisel sizes explained covers how the designations work, including the metric-imperial trap.

The specialists

Corner chisels, skew chisels, fishtails, cranked-neck paring chisels, slicks. All real tools solving real problems, and every one is a purchase made after a specific job has made you want it. Buying a specialist chisel speculatively is how a drawer fills with tools nobody has sharpened.

The short answer

Buy a four-piece bevel-edge bench chisel set. Add two or three mortise chisels if and when you start chopping mortises by hand. Add a long paring chisel when the reach of a bench chisel starts annoying you. That is a complete chisel collection, and most people never get past the first item.