The Smith Little Torch, manufactured by Smith Equipment, is a precision oxy-fuel soldering system widely regarded as the benchmark instrument for delicate bench jewellery work. Operated on a combination of oxygen and a fuel gas — acetylene, propane, or natural gas — the torch produces an exceptionally fine, controllable flame that has made it a fixture in professional jewellery workshops and in the Gemological Institute of America's jewellery manufacturing curriculum. Its defining characteristic is a range of interchangeable tips capable of producing flames as small as approximately 1 mm in diameter, enabling the jeweller to apply heat with surgical precision to a single solder join without disturbing adjacent areas or endangering heat-sensitive gemstones set nearby.

Design and Operating Principles

The torch body is compact and lightweight, designed to be held like a pen or pencil for maximum control during intricate operations. Separate needle-valve controls govern the oxygen and fuel supplies independently, allowing the operator to tune the flame character across the full spectrum from a reducing (fuel-rich) flame to a neutral or oxidising (oxygen-rich) flame. This flexibility is essential in jewellery work: a slightly reducing flame is preferred when soldering gold and platinum alloys to minimise surface oxidation, while flame character adjustments are also used during annealing to judge metal temperature by colour response.

Interchangeable tips are numbered by orifice size, with the smallest tips suited to micro-soldering on fine chain, grain-setting, and repair work on delicate filigree, and larger tips used for heavier fabrication tasks or annealing sheet and wire stock. The tips connect via a standard fitting, and a competent bench jeweller will change tips routinely within a single working session as the task demands.

Applications at the Jewellery Bench

• Soldering: The primary use — joining metal components with hard, medium, or easy solder alloys appropriate to the base metal and the sequence of operations in a multi-join piece.
• Annealing: Restoring ductility to work-hardened gold, silver, or platinum by heating to the correct temperature range and quenching or air-cooling as appropriate to the alloy.
• Repair and sizing: Ring sizing, prong re-tipping, and shank repairs where proximity to set stones demands the finest possible flame control to avoid heat damage to the setting or the stone itself.
• Granulation and fusion: The precise heat control of the Little Torch makes it suitable for granulation work, where gold granules are fused to a surface through a copper-oxide eutectic bond at temperatures that must be held within a narrow window.

Relevance to Gemstone Safety

For the gemmologist and setter, the torch's small flame footprint is directly relevant to stone safety. Many gemstones — emeralds, opals, tanzanites, treated rubies and sapphires, and fracture-filled stones among them — are vulnerable to thermal shock, dehydration, or damage to clarity-enhancing fillers if exposed to excessive or poorly directed heat. The ability to concentrate heat precisely on a metal join, combined with the use of heat-sink compounds (such as Kool Jool or similar thermal barrier gels) applied around a set stone, allows experienced bench jewellers to perform repairs in close proximity to stones that would otherwise require removal from their settings. This capability has practical and economic significance in the trade, where removing and re-setting a stone adds both cost and risk.

In the Trade and in Education

The Smith Little Torch has been a standard specification in GIA's bench jeweller programmes for decades, and its presence in that curriculum has reinforced its adoption across the English-speaking jewellery trade. Independent bench jewellers, goldsmiths, and production setters in North America, the United Kingdom, and Australia commonly cite it as their primary or sole torch. Its longevity in the market — the design has remained substantially unchanged through successive decades — reflects both the soundness of its engineering and the conservative nature of the bench jeweller's toolkit, where proven reliability is valued above novelty.

Fuel choice varies by workshop infrastructure and local supply. Acetylene delivers the highest flame temperature and is preferred for platinum work; propane is more commonly available and adequate for gold and silver; natural gas, where plumbed in, offers convenience and lower running cost for high-volume production environments.