Build a welded steel workbench from your own dimensions

Give three dimensions and a section, and you get the cutting list, the steel to buy, the length of welds and the current. The drawing redraws with the numbers; the list prints, downloads or saves as a link.

A worked example: 1500 × 700 × 850

The version most people start from: a 1500×700 mm top at 850 mm, a frame of 40×40×2, a 4 mm plate and a bottom shelf.

Mass is worked out without the corner radii of the section, so it comes out two to three per cent below the standard tables. No allowance is added for saw kerf or cutting errors: when buying, add one commercial length.

That comes to about 12.3 m of section (three commercial 6 m lengths), 29 kg of frame and 33 kg of top — a little over 60 kg of finished bench.

The order that keeps the frame straight

A bench goes out of square not from bad welding but from the order of work. Heat put in from the same side every time pulls the frame that way, and you only see it once everything has cooled — when straightening is hard.

1. Cut everything and sort it. The four legs must be exactly the same length: 2 mm of difference is a bench that rocks. Cut them as a bundle in one go.
2. Assemble the top frame flat and measure both diagonals before tacking. Equal diagonals are the only proof the frame is rectangular — a square will not show it over 1.5 m.
3. One tack per corner, check the diagonals again, and only then add the rest.
4. Weld the legs with the frame upside down on a flat floor: the legs then set themselves in one plane.
5. Weld corners alternately, diagonally opposite, each with a short run rather than all the way round at once.
6. The top goes on last, stitched every 200–300 mm. A continuous weld round a 4 mm plate dishes it, and that does not come back out.

Welding settings

A 2 mm wall is already thin material: the current you normally use burns a corner away in a second. The values are the same as on the welding square tube page; the calculator above shows the row for the wall thickness you chose.

Materials and weight, part by part

A 1500 × 700 × 850 bench in 40×40×2 tube is thirteen pieces:

• Legs — four of 846 mm: the bench height less the 4 mm top.
• Top frame — two long rails of 1500 mm and two short rails of 620 mm (width less two tubes), plus a 620 mm cross rail under the middle of the top: the calculator adds it once the bench is longer than 1200 mm.
• Bottom frame for the shelf — two of 1420 mm and two of 620 mm.

40×40×2 tube weighs 2.39 kg per metre, so the frame is about 29 kg. The 1.05 m² top weighs about 33 kg in 4 mm plate, about 49 kg in 6 mm and about 66 kg in 8 mm — thick plate doubles the weight of the bench. The pieces lay out like this: the first 6 m bar gives both 1500 rails, one 1420, a leg and a short rail; the second gives the other 1420, three legs and three short rails; from the third bar you need one 620, and the rest is spare for mistakes. The 18 joints and 2.9 m of weld take about 0.05 kg of wire.

The other projects, from a garden gate and a carport to stairs, produce the same cutting list with weights and parts; all of them are gathered on the project calculators page.

Tools you need

• A welder good for 90–110 A on MIG or 70–90 A with a 2.5 rod: the whole frame is one 2 mm wall.
• A chop saw or angle grinder: the legs are cut as a bundle, so a chop saw with a stop is easier.
• A flat base bigger than the bench — a concrete floor checked with a straightedge, or a plate on trestles.
• Magnetic squares for all four corners, 4 clamps, a tape.
• For the top — two or three long clamps to pull the plate down onto the frame before tacking.

Marking out and tacking

A bench needs little marking out, but that little decides whether it rocks. Mark the four legs together: bundle them, square the ends against a stop and run one line across all of them. Mark the height of the bottom frame on the legs from the same end — the one that will stand on the floor — and in the bundle too.

Tacks on 2 mm tube are small and go on two opposite faces of the joint. One tack per corner first, diagonals next, the remaining tacks only after the check. The diagonals of a 1500 × 700 top frame are about 1655 mm, and up to 2 mm of difference on a frame this size is normal.

Settings stage by stage

• Frame and legs — 2 mm wall: 0.8 mm wire, 90–110 A, 17–19 V, or a 2.5 mm rod at 70–90 A. With stick, weld in stitches with pauses.
• Top to frame — 4 mm plate to 2 mm tube. Set up for the thinner part, the tube, and keep the arc on the plate: the plate takes the heat without burning through, and the pool flows onto the tube edge by itself.
• Levelling feet — if nuts or plates for screw feet go under the legs, weld them to the leg ends with the same 2 mm settings, arc on the heavier part.

With a 50×50×3 frame — the option for a long bench and hammer work — the row changes to the 3 mm wall: 0.8–1.0 mm wire, 120–140 A, 19–21 V, or a 3.2 mm rod at 90–120 A.

How not to dish the top

The order above protects the frame. The top has a risk of its own: the plate is thinner and wider than the frame and pulls harder. What helps:

• Clamp the plate down onto the frame along its full length before the first tack: a plate lying with a hump gets welded that way.
• Stitches from the middle out, alternating between the long sides: middle of the left, middle of the right, then out to the corners.
• No continuous weld: stitches every 200–300 mm, as in the order above.

Painting: what to paint and what not to

Paint the frame and legs as usual: dress the welds, degrease, anti-corrosion primer, two coats of enamel. Do not paint the working surface of a welding bench: paint burns and smokes under spatter, and bare metal is where you clamp the earth — the bench becomes part of the welding circuit. Instead of paint, keep the top clean of scale and lightly oiled against rust. If the bench is for assembly and painting rather than welding, the plate can be painted all over.

How long it takes

18 joints and 2.9 m of weld is not much. Most of the time goes on preparation:

• Cutting thirteen pieces — the legs as a bundle so the lengths match.
• Assembly on a flat surface, checking diagonals before and after tacking.
• Welding the frame and top — a short stage if you keep to the order and do not hurry the cooling.
• Painting the frame — with drying times as per the product sheet.

If the bench will be an assembly table for frames, it is worth looking first at the jigs and fixtures that go on it. The rod consumption for the whole bench comes from the electrode consumption calculator.

What usually spoils the job

Beginner mistakes on a workbench

• Legs cut one at a time. A couple of millimetres of difference and the bench rocks; the only cure is trimming after welding.
• Assembly on an uneven floor. The floor's shape goes into the frame: one leg hangs in the air.
• Top before shelf. The plate blocks access to the top frame joints and the bottom frame gets welded by feel.
• A painted working surface. It burns under spatter and gets in the way of the earth clamp.
• "Standard" height. A comfortable height depends on your height and the work; check it against your elbow before cutting the legs.

Author: Dmitry Frolov, welder and metal fabricator Updated: 28 September 2026