A complete guide to precision craft knives

A craft knife is a handle and a replaceable blade, and almost everything written about them is about the blade. That leaves the more consequential half undiscussed, because the handle decides three things the blade cannot: which blades you are able to fit, how much pressure you can safely apply, and whether your hand still works after an hour.

4D stocks twenty-three Excel handles. This is how they divide up.

A word on "X-Acto"

If you have read about craft knives online you will have met the term. It is an American brand name that became a generic term over there, in the way that Hoover did here. In Britain the words people actually use are craft knife, hobby knife or scalpel, and a tutorial saying "X-Acto knife" means nothing more specific than a light-duty craft knife of the sort below.

Light duty, for detail

Slim, light handles taking fine blades. These are for accuracy rather than force: paper, card, foamboard, thin plastic sheet, film, decals and model cleanup. The blade does the work and your hand simply steers it.

The K1 is the one to start with, a lightweight knurled aluminium handle and the most-sold knife in the range. The K3 and K18 are close relatives.

For long sessions, the K26 has a cushioned grip, which is worth having if you are cutting for hours rather than minutes. The K30 and K17 plastic art knife round out the group.

Medium and heavy duty, for pressure

Thicker handles taking thicker blades, for when the material fights back: chipboard, leather, dense foam, thick card, soft wood. The difference is not just grip. A heavier handle holds a heavier blade in a larger collet, so nothing flexes when you lean on it, and blade flex is what makes a cut wander.

The K2 is the general medium-duty answer, with the K5 and K6 for heavier work again.

This is the choice most people get wrong, and they get it wrong in the same direction: pushing harder on a light knife rather than picking up a heavier one. That is how fine blades snap and how cuts wander.

Specialist handles

The K4 holds a swivelling blade, so the blade rotates to follow a curve while your hand keeps going in a straight line. Fitted with a 360 degree swivel blade it is the right tool for cutting curves in vinyl, film and masking.

The K7 takes carving blades and gouges for shaping rather than cutting. The K11 safety scraper holds a single-edge blade for removing paint, adhesive and residue from flat surfaces, which is a job that ruins craft blades.

Utility and snap-off

Different tools that happen to be knives. A utility knife takes a thick trapezoid blade for cardboard, carpet, packaging and rope, where a craft blade would simply fold.

The K60, K9 and K870 take standard utility blades, including the 2 notch and straight utility blades.

Snap-off knives work differently again: a long segmented blade that you snap back to expose a fresh edge. The K10 and K70 take 9mm blades, and larger handles take 18mm. They are excellent value for anything that blunts blades fast, and poor at precision, because a long thin blade flexes.

Which to buy first

Most people end up with two: a light knife for detail and a heavier one for everything that needs pushing. That pair covers more ground than any single knife can.

Before you buy a blade for it

Handles and blades are matched by duty class, not by preference. A light-duty blade will not seat in a heavy-duty handle and a heavy-duty blade will not go into a light one, whatever shape either of them is.

The compatibility chart on our Excel page lists every replacement blade against the handles it fits, so you can check before ordering rather than after.