Choosing a Leg Vise for Blacksmith Work

Why a Leg Vice Earns Its Place in the Forge

A bench vice is built for woodworking and light metalwork, and it does that job well. Put a length of hot bar in one and start swinging a hammer, though, and you will soon find its limits. The whole force of your blow travels into the screw and the mounting bolts, and something has to give. A leg vice — sometimes called a post vice or stump vice — solves that problem by design. Its rear jaw is fixed to a post or bench leg, and the entire front assembly hangs on a long iron leg that reaches the floor. When you hammer, bend or twist, the load runs down that leg and into the ground rather than through the thread.

That single feature is why leg vices survive for a century or more in working forges, and why they can take a beating that would wreck a bench vice in an afternoon. They also open far wider, hold irregular shapes better, and will grip a bar so firmly that you can lean your whole weight on it. If you do any serious hot work, it is the one tool worth hunting down properly.

Start With Jaw Alignment

Before you get excited about anything else, check that the jaws meet properly. Close them on a short piece of thin flat bar, or hold a steel rule across the jaw faces, and look for daylight. The faces should meet across their full width, both side to side and front to back. A vice whose jaws only kiss in one corner will mark your work, let hot metal shift at the worst moment, and frustrate you every time you use it.

Next, test for rocking. Grip a short length of bar in the centre of the jaws and try to move it up and down. A little play in a hundred-year-old tool is normal and harmless. A lot of movement means worn pivots, a splayed jaw, or a tired screw, and that is much harder to put right.

The Spring — Small Part, Big Difference

Behind the jaws, on the moving side, there should be a flat spring or coil spring that pushes the jaw open. Open the vice and let go. The jaws should fall apart on their own, briskly and without help. If they stay shut, or barely creep open, the spring is tired, snapped or missing altogether.

This is not a dealbreaker — a replacement is easy to forge from a scrap of leaf spring or a sliver of tool steel — but do factor it into the price and your plans. Without a working spring you will be holding the jaw open with one hand while you position hot metal with the other, which is miserable and faintly dangerous. A good spring is one of those things you only notice when it is not there.

Screw, Nut and the Wear That Matters

Wind the vice fully open and fully closed. The screw should run smoothly and quietly, without grinding, jumping or tight spots. Most leg vices use a square or Acme-style thread, which is forgiving of a bit of grit but does wear over decades of use.

Some vices have an enclosed screw, where the thread is hidden inside the front jaw. These keep the muck out, but they also hide wear, so test them carefully. Open-screw vices are easier to inspect and to clean. Whichever you have, grip the moving jaw and waggle it gently. If it drops noticeably before the thread takes up, the screw or nut is worn. That can be re-cut or replaced, but it is a job for someone with a lathe, so treat it as a bargaining point.

Finally, check the handle spins freely in its eye, and that the thrust washer or knuckle behind it is not cracked. A stiff, seized handle is a small annoyance that becomes a large one when you are working quickly.

Size, Weight and the Jobs You Have in Mind

Leg vices are usually described by jaw width, and weight follows size closely.

• 100mm (4in) jaws — the sweet spot for most hobby forges and small workshops. Light enough to move, strong enough for serious bending, twisting and filing.
• 125–150mm (5–6in) jaws — heavy work and long sessions. Expect 25–40kg or more, and a correspondingly sturdy mounting.
• 75mm (3in) and smaller — lovely for fine work and jewellery-scale pieces, but limited grip on big stock.

Weight means stability. A vice that is too light will walk around its post when you strike it, and you will spend half your time re-tightening bolts. If you have the choice, buy the heavier one.

Mounting Height and Fixing

Height matters more than most beginners expect. Stand at the vice as you would when working. A good starting rule is to set the top of the jaws at roughly the height of your knuckles with your arm hanging relaxed — around 850–950mm for most people. Mount it slightly lower for heavy bending where you lean your weight in, and slightly higher if you do a lot of filing and sawing. If in doubt, mount it a fraction high and stand on a mat or a low block.

Fix the rear jaw to a solid wooden stump or a heavy bench leg with two good bolts, ideally coach bolts. The leg must reach the floor, sitting on a steel plate or a firm block so it cannot dig in or rust away. Some smiths set it into a shallow socket or a plate with a lip, so it cannot slide sideways under load. Keep the leg vertical, or very slightly angled, so the force of your hammer goes straight down into the ground.

Buying Secondhand

Boot sales, farm sales, house clearances and auction sites are where leg vices turn up, usually covered in rust and often cheap. Prices vary wildly, but a sound 4in vice is worth hunting for.

When you inspect one, bring a short piece of bar with you and test the grip properly. Check the spring, the jaw alignment, the screw, and whether the leg is straight — a bent leg is awkward to mount and hard to straighten. Look for cracks in the beam or around the mounting plate. Repairs near the beam on a cast vice are usually best avoided. Wrought iron ones, which are older and often heavier, can be welded if needed. Buy well once and the tool will outlast you.