Why Make Your Own Punches and Chisels?

There is a particular satisfaction in reaching for a punch you forged yourself, knowing exactly what steel is in it and how it was treated. Shop-bought punches and chisels are perfectly serviceable, but they are made to a price and to a generic set of dimensions. When you make your own, you can tailor the shank diameter to your hand, the taper to the work, and the point geometry to the job in front of you.

It is also one of the best exercises a new blacksmith can undertake. A punch or chisel is small enough to forge in an afternoon, yet it teaches you drawing out, tapering, edge geometry, heat treatment and tempering — the whole core of the craft in miniature. Get these right and every blade, drift and bolster you make afterwards will be the better for it.

Choosing and Preparing the Steel

You want a steel that will harden reliably and stand up to being struck. The traditional choice in Britain is silver steel — a water-hardening, high-carbon tool steel sold in bright ground bars — but there are plenty of good alternatives.

• Silver steel (BS 1407) or W1: hardens in water, forges cleanly, available in every useful diameter.
• O1 gauge plate or oil-hardening rod: more forgiving in the quench, less prone to cracking, excellent for fine punches.
• 1080 or 1084: a simple high-carbon steel that takes a keen edge and tempers predictably.
• Salvage steel: old coil springs, Allen keys, hay rake tines and worn files all make serviceable tools once annealed.

Avoid anything galvanised, chromed or of unknown parentage that sparks dull red and short. If in doubt, cut a test piece, forge it and harden it before committing to a whole set. Bars of 8–12mm diameter or 10mm hex are ideal for punches; chisels benefit from a slightly chunkier 12–16mm stock so the head can take a hammer blow.

Forging the Profile

Work at a good bright orange, and keep your heats short and frequent. Long soaking heats at welding temperature will grow the grain and leave you with a brittle tool. For a punch, start by drawing a taper down to roughly 60–70% of the shank diameter over the last 40mm, then form the point.

Point geometry matters more than most beginners expect:

• Centre punch: a 60–90° cone, sharpened to a fine but not needle point.
• Prick punch: a slimmer 30–40° cone for marking out.
• Cold chisel: a cutting edge of around 60° included angle — steeper for harder metals, shallower for brass and copper.
• Hot cutter: a slimmer 30–40° edge, since it will be used on orange-hot steel.

Forge the striking end into a gentle dome rather than a sharp mushroom, and keep it concentric with the shank. An off-centre head will send the tool skittering the first time you hit it hard.

Normalising and Hardening

Before hardening, normalise the tool. Heat it to just above non-magnetic — a good dull orange — and let it cool in still air. Repeat three times. This refines the grain and relieves the stresses you have just hammered into the steel, and it is the step most often skipped.

Now bring the cutting end only up to hardening temperature. For silver steel that is around 780–800°C, a cherry red just past the point where a magnet stops sticking. Do not let the whole tool get hot; you want a hard working end and a softer, tougher shank.

Quench vertically, point down, plunging the tool up and down in the water or warmed oil rather than swirling it sideways. Movement along the axis cools evenly and discourages warping. Hold it there until the hissing stops and the steel is cool enough to touch. A file should now skate across the hardened end without biting.

Tempering by Colour

Hardened steel is glass-brittle. Tempering is what turns it into a tool. Polish the hardened end to bright metal, then warm the shank gently — a gas torch, or the residual heat from the shank itself if you quenched only the tip. Watch the oxide colours run down towards the point.

• Punches and marking tools: quench at pale straw to dark straw, roughly 220–240°C.
• Cold chisels: quench at brown to purple, around 250–280°C.
• Hot cutters and hot chisels: quench at blue, 300°C or a touch beyond.

Have a tin of water ready. The moment the right colour reaches the cutting edge, dunk it. If you overshoot into blue, re-harden and try again — the colour will not come back.

Handles, Edges and Looking After Them

A bare chisel is perfectly traditional, and if you keep the head domed and dressed with a file, it will serve for years. Punches benefit from a short wooden handle turned to a comfortable grip, or simply a few wraps of leather. Whatever you choose, keep the striking end free of cracks and never let a mushroom develop — that is how fragments end up in someone's eye.

Sharpen chisels on a fine stone, maintaining the forged angle, and grind back only enough to restore the edge. Store your set in a rack or roll so the points do not knock against one another. Made properly, a set like this will outlast most of what you can buy, and you will know every heat that went into it.