Jeweller's Saw
Jeweller's Saw
The fine-toothed deep-throat handsaw used for piercing and cutting metal sheet at the bench
The jeweller's saw is the principal cutting tool at the goldsmith's bench, used for piercing fine designs into metal sheet, cutting components from stock, and shaping rough castings before filing. It consists of a U-shaped steel frame, an adjustable thumbscrew clamp at each end, and a thin replaceable blade tensioned between them. The throat depth, typically between 50 and 200 millimetres, defines the maximum reach into a sheet of metal.
Frame and Blades
Frames are sold in fixed and adjustable patterns. The adjustable frame allows the use of broken blades by sliding the thumbscrew clamps along the frame to a shorter working length, a practical consideration in a workshop where blades are consumed quickly. The standard blade length is approximately 130 millimetres, fitted with the teeth pointing downwards toward the handle so that the cut is on the down-stroke.
Blade grades are numbered from coarse to fine. The standard scale runs from 14 (heaviest, about 1.0 millimetres thick) through 8 (heavy), 4 (medium), 2 (general work), 1 (fine), and 0 down to 8/0 (very fine). General piercing of 1-millimetre sheet uses around grade 2 to 4. Fine work in 0.5-millimetre sheet uses grades 0 to 4/0. Stone-setting cut-down work and filigree often use 6/0 and finer.
Tension and Use
The blade is tensioned by clamping at the upper end first, slightly compressing the frame, then clamping the lower end. A correctly tensioned blade, when plucked, gives a clear high musical tone; a loose blade flexes and breaks. Lubrication with beeswax or proprietary saw lube reduces friction and extends blade life. The saw is held vertical and moved with light pressure, allowing the teeth to do the cutting; pressure causes binding and breakage.
Common operations include external piercing, internal piercing through a drilled start hole, straight cuts on flat sheet, and curved cuts following a marking-blue or transferred drawing. The bench pin at the front of the workstation supports the work, with a vee notch in the pin allowing the blade to clear during the cut.