Why the hammer decides where the metal goes

Drawing out is the smith's bread and butter. You take a length of square bar, heat it to a good bright orange, and persuade the steel to grow longer and thinner without cracking or folding on itself. Almost everything about how that happens — how quickly, how cleanly, how evenly — is settled by the hammer in your hand. A heavy flat face spread over too much of the work will simply flatten and widen it. A narrow peen, aimed properly, will push metal along the bar like butter under a knife. Understanding that difference is what turns a rack of hammers from clutter into a set of tools.

Cross-peen, straight-peen and rounding: what each face does

Nearly every drawing hammer falls into one of three families, and the shape of the peen tells you the direction the metal will travel. A wedge concentrates the blow into a line, and steel flows away from that line at right angles to it. That single fact underpins everything.

• Cross-peen. The peen runs at right angles to the haft. Strike it with the peen crossing the bar and the metal is driven lengthways, straight down the bar away from the blow — the classic drawing-out blow. Because the direction of flow sits across your swing, you can keep the bar at a comfortable angle and simply rotate it a quarter turn between blows to keep the section even. This is the hammer most smiths reach for first when a taper or a long taper needs to happen.
• Straight-peen. The peen lies in line with the haft, so the wedge runs along the bar and the metal moves sideways, widening rather than lengthening. It is superb for spreading a section, setting a shoulder, forging close to the horn or anvil step, and for drawing out where your stance makes a cross-peen awkward. Turn the work 90 degrees and it draws out perfectly well too — you are simply changing which direction the bar lies relative to your swing.
• Rounding hammer. One flat face, one domed. The domed face contacts the steel over a small area, so it concentrates force and moves metal in almost any direction you choose, leaving shallow, easily-dressed marks rather than the deep line of a peen. That makes it wonderfully forgiving for general drawing out, for truing up a taper and for finishing a surface. Many working smiths now use a 1kg to 1.3kg rounding hammer for the bulk of their forging and keep the peens for specific jobs.

Choosing a weight that suits your arm and your stock

Weight is where beginners most often go wrong. A 2kg hammer swung with a tired arm moves far less steel than a 1kg hammer swung with control, and it will wreck your elbow into the bargain. As a rough guide:

• 700g to 900g. Light work — small scrolls, hooks, fire irons, chasing, and long sessions where stamina matters more than speed.
• 1kg to 1.3kg. The all-rounder. Comfortable on 12mm to 25mm square stock and the weight most people should own first.
• 1.4kg to 1.8kg. Heavy drawing out on thick bar, breaking down a billet, or moving a lot of metal in a short heat.

The rule of thumb is simple: pick the heaviest hammer you can swing accurately for the whole session, not the heaviest you can lift.

Face dressing, handles and the details that matter

A hammer straight off the shelf is rarely ready for fine work. Sharpen the edges of a flat face and you will leave deep creases that turn into cold shuts when you forge them in. Chamfer the rim on a linisher, polish the face, and keep the dome of a rounding hammer smooth. A cross-peen wants a neat radius on the wedge too — roughly 3mm along the edge — so it sinks in rather than cuts.

Check the head and handle every session. A loose head, a cracked haft or a mushroomed face is a workshop accident waiting to happen. Fit a hickory or ash handle about 300mm to 350mm long, wedged properly, set the head so it sits square, and hold the haft near the end with a relaxed grip. Let the hammer do its work; if your knuckles are white, the metal is losing.

Matching the tool to the job

Most drawing out goes best at a good yellow-orange heat, with the steel turned a quarter turn between blows so you are forging down to a square and then to a round as you choose. In practice:

• Long tapers and fire irons: cross-peen, rotating the bar as you go.
• Spreading a flat section or setting a shoulder: straight-peen.
• General breakdown, tidying and planishing: the flat face of a rounding hammer.
• Heavy reduction of thick stock: the heaviest hammer you can still aim, then finish with something lighter.

Owning fewer hammers, and knowing them better

A great many old cross-peens and ball-peens come out of car boot sales, auctions and house clearances, often with a lovely worn face and a handle someone replaced in 1974. Re-dress the face, re-haft it properly, and you have a tool that will outlive you. Two or three hammers — a well-dressed cross-peen around 1kg, a straight-peen of similar weight, and a rounding hammer — will cover almost everything a working smith does at the anvil. Get to know them intimately: how they sit in your hand, how much steel they move per blow, how your wrist and anvil height work together. The hammer is the only part of the anvil's tooling that is always in your hand, and it rewards attention more than any other purchase you'll make.