Draw-bench tube — also known as jeweller's tube or drawn tube — is small-diameter metal tubing produced by pulling a length of metal stock through successively smaller apertures in a drawplate or draw-bench, reducing its outer diameter and wall profile to precise, repeatable dimensions. The process is a cornerstone of traditional jewellery fabrication, yielding tubing of uniform wall thickness and consistent roundness that would be difficult or impossible to achieve by casting or simple rolling alone. The resulting tube is used across a wide range of structural and decorative applications: tube settings for stones, bezel blanks, hinge barrels, rivet sleeves, decorative gallery elements, and the internal armatures of articulated jewellery.

The Draw-Bench and Its Components

A draw-bench is essentially a horizontal frame — historically of hardwood, today more commonly of welded steel — fitted at one end with a fixed drawplate and at the other with a toothed chain or rack-and-pinion mechanism driven by a hand crank or, in production workshops, an electric motor. The drawplate is a hardened steel plate (or, in finer work, a tungsten-carbide insert plate) pierced with a series of tapered holes graded by diameter. Each hole is slightly smaller than the last, and the taper on the entry side guides the metal smoothly into the reduction zone before it exits through the parallel land — the short cylindrical section that imparts the final diameter.

For tube drawing specifically, the workpiece must first be prepared as a hollow form. The jeweller typically begins with commercially supplied tubing of a larger diameter, or fabricates a seamed tube by forming a strip of sheet metal around a mandrel and soldering the seam before drawing. Once the starting tube is prepared, one end is tapered — by filing or hammering — to a point narrow enough to pass through the target hole in the drawplate. Draw tongs or a purpose-made grip are attached to this tapered end, and the chain or rack mechanism pulls the tube through the hole in a single, steady stroke.

The Reduction Process and Work-Hardening

Each pass through the drawplate reduces the outer diameter by a controlled increment — typically between two and five per cent of the cross-sectional area per pass, depending on the metal and the jeweller's judgement. As the tube is drawn, the metal's crystalline grain structure is elongated in the direction of drawing, a phenomenon known as work-hardening or strain-hardening. The tube becomes progressively stiffer and less ductile with each successive pass. If drawing continues beyond the metal's capacity to deform without fracturing, the tube will crack or split — a failure mode particularly common at soldered seams if the solder alloy and parent metal have significantly different hardness characteristics.

To restore ductility and allow further reduction, the jeweller anneals the tube periodically — heating it to the appropriate temperature for the alloy in question (for sterling silver, approximately 600–650 °C; for 18-carat yellow gold, approximately 700–750 °C) and quenching or allowing it to air-cool. Annealing recrystallises the grain structure, relieving internal stress and returning the metal to a workable state. The cycle of drawing, annealing, and drawing again is repeated until the target diameter is reached. The final pass is typically performed without subsequent annealing, leaving the tube in a work-hardened state that provides the rigidity required for settings and structural elements.

Metals Commonly Drawn

Virtually any ductile metal used in jewellery fabrication can be drawn into tube, provided it has sufficient elongation before fracture. The most commonly drawn metals in a jewellery context include:

• Sterling silver (92.5% Ag) — highly ductile, anneals readily, and draws cleanly; the standard training metal for learning tube-drawing technique.
• Gold alloys — yellow, white, and rose gold in 9-, 14-, and 18-carat formulations are all drawn commercially and in the workshop; white gold alloys containing nickel work-harden more rapidly than yellow gold and require more frequent annealing.
• Platinum and platinum alloys — drawn tube in platinum is used for high-end settings and hinges; the metal's high melting point and work-hardening rate demand careful technique and specialised annealing equipment.
• Copper and brass — used in base-metal prototyping, costume jewellery, and educational contexts; both draw easily and are forgiving of technique errors.

Applications in Jewellery Fabrication

The versatility of drawn tube makes it one of the most frequently reached-for materials in a fabrication workshop. Its principal applications include:

• Tube settings — a short section of drawn tube, its wall thickness matched to the girdle diameter of a round stone, is soldered into a pierced seat in a ring shank or pendant. The upper edge is then burnished or pushed over the stone's girdle to secure it. The uniformity of wall thickness that drawing produces is essential here: uneven walls would create an asymmetric setting that is both visually poor and structurally weak.
• Bezel blanks — for cabochon stones, a length of tube whose inner diameter approximates the stone's base can be sliced into short cylinders, each of which becomes the starting blank for a bezel setting. The jeweller adjusts the fit by stretching or compressing the blank on a mandrel.
• Hinge barrels — the knuckles of a box clasp or locket hinge are sections of drawn tube through which a wire pin is passed. The precision of drawn tube is critical here: the inner diameter must be consistent along the full length of the barrel for the pin to move freely without play.
• Decorative gallery elements — short lengths of tube can be incorporated into gallery structures, used as spacers between layers of a fabricated piece, or cut and shaped into decorative motifs.
• Rivet sleeves — in cold-connection work, tube rivets pass through drilled holes in stacked elements; the tube is then flared at both ends to lock the assembly without solder.

Drawplate Geometry and Tolerances

Commercial drawplates for tube are available in a range of hole-size progressions, typically spanning from approximately 0.5 mm to 10 mm in outer diameter, with increments of 0.1–0.5 mm between adjacent holes. The taper angle of the entry cone — usually between 10° and 20° included angle — affects the drawing force required and the degree of work-hardening per pass: a shallower taper distributes deformation over a longer contact length, reducing peak stress but increasing friction; a steeper taper concentrates deformation and can cause surface cracking if the metal is not sufficiently ductile. Tungsten-carbide drawplates maintain their hole geometry far longer than hardened steel plates and are preferred in production environments where consistent tolerances are essential.

Lubrication is applied to the tube before each pass to reduce friction and surface scoring. Traditional lubricants include beeswax, tallow, and proprietary drawing compounds; the choice depends on the metal and the surface finish required on the drawn tube.

Seamed Versus Seamless Tube

Drawn tube in a jewellery workshop may be either seamless or seamed. Seamless tube — produced commercially by extrusion or piercing — has no longitudinal joint and is structurally uniform around its circumference. Seamed tube, fabricated by the jeweller from a strip of sheet metal formed into a cylinder and soldered, is adequate for most applications but requires that the solder alloy be compatible with the parent metal and that the seam be positioned away from areas of maximum stress during subsequent drawing and forming. A poorly made or incorrectly positioned seam is the most common cause of tube failure during drawing. For hinge applications and other mechanically demanding uses, seamless tube is generally preferred.

In the Trade

Commercial suppliers of precious-metal findings offer drawn tube in standard outer diameters and wall thicknesses, sold by the troy ounce or by the linear centimetre, depending on the supplier's convention. Jewellers typically purchase tube at a diameter somewhat larger than their final requirement and draw it down in the workshop to achieve the precise fit needed for a specific stone or design element. This practice allows a single commercial stock size to serve a range of finished dimensions, reducing inventory requirements. The additional work-hardening imparted by the final workshop drawing passes is often a deliberate benefit, producing a tube that is harder and more resistant to deformation in service than the as-supplied commercial stock.

Bench jewellers working in the Arts and Crafts and studio jewellery traditions have long regarded the ability to draw tube accurately as a mark of fundamental craft competence. The skill involves reading the metal's response — listening and feeling for the change in resistance that signals the onset of over-hardening, judging anneal temperature by colour in subdued light, and maintaining the steady, controlled pull that prevents the tube from twisting or ovalling in the drawplate. These are tactile and experiential skills that remain largely unchanged from the practices of nineteenth-century goldsmithing workshops.

Further Reading

• Gems & Gemology — GIA Publications
• Ganoksin: Tube Setting Techniques