Pancyprian TS Jewellery III cheat sheet

Pure gold is 24 karat; karat fraction = karat/24, so 18 kt = 0.750 fine and 14 kt = 0.585 fine.

Precious-metal content in parts per thousand is the millesimal fineness: 750 = 18 kt, 916 = 22 kt, 999 = fine gold.

Sterling silver is 925/1000 silver with copper balance; fine silver is 999 and is softer and whiter after finishing.

Platinum jewellery alloys are typically 950 Pt with iridium, ruthenium or cobalt; Pt 950 with Co is harder and easier to cast than Pt 950 with Ir.

Common 18 kt yellow gold: 750 Au with Ag and Cu balance; increasing copper raises redness and hardness, increasing silver lowers colour saturation.

Density comparison used to distinguish metals: fine gold 19.3, sterling silver 10.3, copper 8.9, platinum 21.4 g/cm3.

Nickel in white gold alloys is a sensitizer; EU-style practice uses palladium or silver-white alloys to avoid nickel release.

Melting ranges: fine silver about 961 C, sterling about 893 C solidus, fine gold 1064 C, 18 kt yellow gold roughly 880-920 C.

Piercing saw frame takes blades 0.2-0.4 mm thick; blade is mounted with teeth pointing toward the handle and tensioned by shortening the frame.

Bench peg is mounted at about chest height with the V-notch facing the worker; work is supported on the peg, not on the bench top.

Files are graded by cut number: 0 and 1 are coarse for stock removal, 4 and 6 are fine for finishing and stone-seat cleanup.

A graver is sized by its square blank and shaped by the cutting angle; a 45-degree face with about 10-degree heel is a common onglette geometry.

Eye protection to EN 166 impact rating is required for grinding, sawing and polishing; dust and vapour extraction is required for polishing and soldering.

Torch safety: check hoses and regulator with soap solution, keep flame away from fuel canisters, and never use a leaking torch.

Rotary burs run at the lowest speed that cuts; carbide burs need higher speed than steel burs, and both require lubrication and light pressure.

Ring sizes are expressed as inner diameter in mm or as a circumference-based scale; circumference = pi x inner diameter.

A vernier or digital caliper reads to 0.01 mm; for a ring mandrel, measure the inner diameter at the widest point, not the tapered side.

Metal thickness and wire gauge tables are non-linear: 0.8 mm sheet is much thicker than 0.8 mm gauge number in the Brown & Sharpe system.

Scribing uses a sharp steel scriber and engineer's blue or a marker coat; a pencil line is not accurate enough for setting out solder seams.

Orthographic jewellery drawings show plan, side and section; a section view is required to communicate wall thickness and stone-seat depth.

Scale drawings of a setting use the stone's girdle diameter and depth; the seat is drawn at 60-80 percent of the stone depth.

Tolerances on a jewellery drawing are typically plus or minus 0.05 mm for setting work and plus or minus 0.1 mm for general benchwork.

Sawing rule: use the coarsest blade that fits the curve; two to three teeth in contact with the metal at all times.

For piercing internal shapes, drill a starter hole, thread the blade through, re-tension, then cut on the waste side of the line.

Draw filing is done with the file held at 90 degrees to the work and pushed sideways to flatten and remove saw marks.

Cross filing follows the surface at about 30-45 degrees to the work axis to remove stock quickly and keep a flat plane.

Drilling: centre punch first, use a drill speed that gives a continuous chip, and lubricate with a suitable cutting fluid.

Drill sizes for jewellery follow the number and letter series; a 1.0 mm twist drill needs high speed and light feed in precious metal.

File edges are safe (uncut) on one side for filing into a corner; never file a stone seat with a coarse cut.

Burs and drills should be run true; a bent shank causes chatter and oversize holes.

Solder flows toward the heat source and into the hottest joint area; the whole piece must reach soldering temperature before the solder is applied.

Solder grades match the parent alloy: extra-easy, easy, medium and hard solders melt in descending order, so use hard first and easy last.

Flux prevents oxidation and lowers surface tension; borax-based flux suits gold and silver, while fluoride fluxes suit stainless and some white alloys.

Annealing: heat to a dull red for silver and gold alloys, hold briefly, then quench in water; sterling can be quenched from red heat.

Do not quench white gold or alloys containing nickel or cobalt from red heat; allow air cooling to avoid cracking.

Anti-oxidation: coat the piece with flux or a protective borax wash before annealing to limit firestain on sterling silver.

Pickle removes oxide and flux residues; use warm dilute acid with copper or brass tongs only, never steel, to avoid plating the work.

Hardening of some alloys is by precipitation: heating and holding at a set temperature then quenching, followed by ageing, as with some platinum and gold alloys.

Annealing is required before bending or forming; work-hardened metal cracks if formed without a stress-relief anneal.

Rolling reduces thickness and elongates the metal in the rolling direction; anneal between reductions of about 50 percent to avoid edge cracking.

Ring bending uses a mandrel and mallet; the ring is formed oversize and then brought to size after the seam is soldered.

Doming and anticlastic forming use stakes and hammers; a planishing hammer with a polished face leaves a smooth surface.

Finishing sequence: file, then abrasive paper from coarse to fine, then tripoli polish, then rouge or a final high-colour polish.

Polishing compounds are matched to metal: tripoli for gold and silver pre-polish, rouge for final colour, and a separate mop for each compound to avoid contamination.

Matte and satin finishes are produced with abrasive paper, a bristle brush or pumice; a matte finish should be applied before the final assembly of stones.

Electroplating and rhodium plating require a clean, grease-free surface; rhodium is used on white gold to give a bright white finish.

Mohs hardness: talc 1, gypsum 2, calcite 3, fluorite 4, apatite 5, orthoclase 6, quartz 7, topaz 8, corundum 9, diamond 10.

Stones of hardness 7 or above are safe for daily-wear rings; opal, pearl, turquoise and emerald need protective settings and care.

Claw setting: claws are cut to a uniform length, the stone is seated level, then claws are pushed over the girdle and filed to shape.

Bezel setting: the wall is pushed over the stone with a pusher, then burnished; the bezel wall thickness should be about 0.5-0.8 mm.

Pavé setting uses small stones set close together; the beads are raised from the metal between stones with a graver and burnished.

A stone seat must be cut to the stone's girdle diameter and depth; a seat that is too deep hides the stone and weakens the setting.

Gemstone cleaning: no ultrasonic or steam on emerald, opal, pearl, turquoise or fracture-filled stones; these need soft cleaning only.

Heat protection: remove or protect heat-sensitive stones before soldering; borax and water-soaked tissue or a heat shield can protect a set stone.

Findings include jump rings, clasps, bails, ear wires, posts and backs; they are chosen by function, metal and required strength.

Jump ring strength: a soldered jump ring is a permanent connection, an unsoldered ring can open under load; use soldered rings at clasp points.

Lobster clasps are stronger than spring rings; magnetic clasps are not suitable for valuable or heavy pieces.

Hinge construction requires a knuckle with a tube and a pin; the pin should be a close sliding fit and secured at one end.

Box clasps and tongue-and-groove clasps must be aligned before soldering; test the fit cold before final assembly.

Ear wires: hook wires suit light earrings; posts with friction backs suit studs; lever backs add security for heavy earrings.

Chain repair: match the link size and wire gauge, use a soldered joint, and check the chain for wear at the clasp before returning it.

Quality checks: solder seams fully flowed, no pitting or firestain, stone secure and level, clasp functions, and finish uniform.

Hallmarking is a legal requirement in many jurisdictions; the mark records metal fineness and often the maker and assay office.

Repair assessment: check for previous repairs, solder grade used, stone security and metal thickness before quoting or working.

Sizing a ring down requires removing a section and re-soldering; sizing up requires inserting metal; both must preserve the hallmark and setting alignment.

Record-keeping: photograph the item before repair, record the metal, stones, weight and agreed work, and give a written estimate.

Never work on an item with an unknown stone without the client's informed consent; heat and chemicals can damage it.

Professional practice: use separate tools for base metals and precious metals, and keep a clean bench to avoid cross-contamination and scratches.

Casting defects: porosity shows as pitting after polishing; gas porosity comes from trapped gas, shrinkage porosity from thick sections feeding thin ones.

Pickle after soldering, rinse in clean water, then dry before polishing to avoid trapping acid in seams.

Burnishing with a steel or agate tool compresses the surface and improves reflectivity without removing metal.

A scratch is removed by going one abrasive grade coarser than the scratch depth, then working back up through the grades.

Weighing: use a balance accurate to 0.01 g for precious-metal accounting; record weights before and after work.

Fume and dust control: polishing dust contains precious metal and must be collected; extraction protects both health and material recovery.

A working drawing must state metal, alloy, dimensions, stone sizes and quantities, finish and any hallmarking requirement.

Use a consistent scale and dimension from a single datum to avoid cumulative error in a multi-part assembly.

Section views communicate seat depth, wall thickness and hinge knuckle size; hidden detail is shown with dashed lines.

Stone layout drawings use the girdle diameter plus the setting allowance, not the stone's total depth, to space stones.

Revision control: number drawing revisions and record the change; bench work should follow the latest released revision.

Refractive index and specific gravity are the standard identification tests; a refractometer reads RI on a polished facet.

A gemstone's RI must be read on a flat facet; rough or cabochon stones cannot be read on a refractometer.

Double refraction is seen in anisotropic stones such as quartz, corundum and peridot; glass and diamond are singly refractive.

Thermal conductivity separates diamond from simulants; a diamond tester distinguishes diamond from cubic zirconia and glass.

Storage: keep diamonds and hard stones separate from softer stones to avoid abrasion; pearls should be stored away from heat and chemicals.

Handling: use tweezers with protected tips for stones; fingerprints and skin oils affect appearance and can stain porous stones.

Soldering requires local fume extraction; metal fume and flux fumes are respiratory hazards.

Pickle and plating solutions are corrosive; store in labelled containers, use tongs, and neutralise spills with bicarbonate.

Rotary tools cause entanglement and eye injury; tie back hair, remove loose clothing and wear impact-rated eye protection.

Lead and cadmium-bearing solders and alloys are toxic; avoid them in jewellery intended for skin contact and never mix them with precious-metal work.

Gas cylinders must be secured upright and fitted with flashback arrestors on the torch lines.

A fire extinguisher rated for flammable liquids and electrical equipment should be within reach of the soldering bench.

Match solder to the parent alloy: silver solder for silver, gold solder of the same karat and colour for gold, platinum solder for platinum.

Solder grade is selected by melting temperature relative to the parent alloy, not by colour alone.

Cadmium-bearing solders flow at low temperature but are toxic; use cadmium-free solders for skin-contact jewellery.

Palladium-white gold alloys need higher-temperature solders and may require a protective atmosphere or flux matched to the alloy.

Silver solder on gold is a visible colour mismatch; use gold solder for gold work where the seam will be seen.

Flux residue must be removed before the next soldering step; residual flux can prevent solder flow.

Ring blank length for a given size = inner circumference plus allowance for metal thickness and solder gap.

Measure ring size at the widest inner diameter; a tapered mandrel gives a false reading if the ring is not seated flat.

Bangle and bracelet sizing uses inner circumference; allow clearance for the hand to pass through.

Chain length is measured end to end including the clasp; record the length before repair so it can be restored.

Weight and dimension checks after sizing confirm that the metal removed or added matches the plan.

Use a jeweller's gauge or caliper for stone measurement; the girdle diameter controls the setting seat size.

Electroplating requires a clean, oxide-free surface; any grease or firestain causes poor adhesion and patchy colour.

Rhodium plating is applied over white gold or platinum to give a bright white finish; it wears with time and needs re-plating.

Gold plating thickness is measured in microns; thin flash plating wears quickly on rings.

Ultrasonic cleaning removes polishing compound before plating; rinse and dry fully before the plating bath.

Plating over a solder seam can show a colour difference if the solder alloy differs from the parent metal.

After plating, handle with clean gloves to avoid fingerprints and contamination.

Test every mechanism before final finishing: clasp opens and closes positively, hinge moves freely without play, and ear wires hold securely.

Solder a jump ring at the clasp ends; an unsoldered ring is the most common point of failure.

Check that a hinge pin is captured at both ends and that the knuckle does not bind.

A box clasp must close with a positive click and not open under light pull.

Stone security check: press each stone lightly and look for movement; a loose stone must be re-set before delivery.

Final inspection includes weight, dimensions, finish and hallmark, recorded against the work order.

Written estimates and work orders protect both jeweller and client and record the agreed scope.

Photograph the item before and after work, including any existing damage or previous repairs.

Record metal, alloy, stone details, weights and hallmark before starting any repair.

Inform the client of risks to heat-sensitive or fragile stones before soldering or cleaning.

Keep a record of solder grade and materials used so future repairs can be planned.

Return the item with care instructions and a note of any limitations, such as plated finishes that will wear.

Work hardening increases hardness and reduces ductility; anneal before further forming to avoid cracking.

Sterling silver anneals at about 650-700 C; heat to a dull red and quench in water.

Gold alloys anneal at about 600-700 C depending on alloy; quench or air cool according to alloy type.

Overheating causes grain growth and a coarse, brittle structure; keep the time at temperature short.

Repeated soldering steps anneal the work; plan the order so hard solders are used first.

Some alloys are age-hardened by holding at a lower temperature after solution treatment; follow the alloy supplier's data.

Seat depth is typically 60-80 percent of the stone's total depth; a deeper seat hides the pavilion and weakens the setting.

Bezel wall thickness should be about 0.5-0.8 mm to allow pushing and burnishing without cracking.

Claw thickness at the tip should be sufficient to cover the girdle without covering the table.

Pavé beads are raised from the metal between stones; bead size must be large enough to hold the girdle.

Channel setting requires a uniform groove width matching the stone girdle and a consistent seat depth along the channel.

Check stone level with a straight edge across the table before closing the setting.

Start with the coarsest abrasive that removes the deepest scratch, then progress through each grade without skipping.

Clean the work and change the abrasive or mop between grades to avoid carrying coarse grit forward.

Draw filing flattens a surface; cross filing removes stock quickly but leaves deeper marks.

A file card cleans file teeth; clogged files scratch rather than cut.

Remove file marks completely before polishing; polishing will not hide deep scratches.

Use a separate mop for each polishing compound to prevent cross-contamination.

Centre punch the hole position before drilling to prevent the drill wandering.

Use a drill speed that produces a continuous chip; too fast overheats and work-hardens the metal.

Lubricate with a suitable cutting fluid when drilling precious metals and steel.

For piercing, drill a starter hole, thread the saw blade, re-tension the frame, then cut on the waste side of the line.

Keep two to three saw teeth in contact with the metal; too few teeth cause snagging and blade breakage.

Deburr drilled holes with a larger drill or a countersink to remove sharp edges.

Porosity appears as pits after polishing; it comes from trapped gas or shrinkage during casting.

Shrinkage porosity occurs where thick sections meet thin ones; design with uniform section thickness.

Firestain on sterling silver is a copper oxide layer that appears after heating and polishing; prevent it with a protective flux coat.

Pits and scratches are removed by going one abrasive grade coarser, then working back up through the grades.

Incomplete solder flow leaves a visible seam and a weak joint; re-flux and reheat rather than adding more solder.

Check castings for cracks and incomplete fill before starting finishing work.

Hardness 7 and above is suitable for daily-wear rings; below 7 needs a protective setting.

Cleavage and fracture affect setting choice: emerald and opal need bezel or protective settings, not claw settings under stress.

Porous stones such as turquoise and pearl absorb oils and chemicals; avoid ultrasonic and steam cleaning.

Fracture-filled stones must not be heated or cleaned in ultrasonic baths.

Pearls should be strung with a knot between each pearl and stored away from heat and chemicals.

Use tweezers with protected tips to handle stones and avoid contamination.

Caliper resolution is typically 0.01 mm; read at the widest point of a round section.

Ring size tolerance is typically plus or minus 0.1 mm on inner diameter for a comfortable fit.

Setting tolerances are tighter, often plus or minus 0.05 mm, because the seat must match the girdle.

Weigh precious metal to 0.01 g for accounting; record weights before and after work.

Use a jeweller's gauge for stone measurement; the girdle diameter controls the seat size.

Check dimensions against the drawing at each stage, not only at the end.

Hallmarking records the metal fineness and is a legal requirement in many jurisdictions.

The maker's mark identifies the workshop or individual responsible for the item.

The assay office mark identifies where the item was tested and marked.

A date letter, where used, records the year of assay.

Sizing or repair can remove a hallmark; re-submit the item for hallmarking where required.

Do not stamp a fineness mark on an item that has not been assayed to that standard.

Solder flows toward the heat source; heat the larger mass first so the joint reaches temperature evenly.

Bring the whole piece to soldering temperature before touching solder to the joint.

Use the smallest flame that heats the joint adequately to avoid melting adjacent work.

Keep the torch moving to avoid local overheating and pitting.

Flux must be applied before heating and must not be burned off before the solder is placed.

Quench or cool according to the alloy and stone content; never quench a piece with heat-sensitive stones.

Lobster clasps are stronger than spring rings and suit heavy or valuable pieces.

Magnetic clasps are not suitable for valuable or heavy jewellery.

Solder jump rings at clasp attachment points; unsoldered rings can open under load.

Ear wires: hook wires suit light earrings; posts with friction backs suit studs; lever backs add security for heavy earrings.

Bails must be large enough for the chain or cord to pass freely.

Match findings to the metal of the piece to avoid colour mismatch and galvanic effects.

Check for previous repairs and the solder grade used before heating the item.

Assess metal thickness and stone security before quoting or starting work.

Photograph the item before repair and record metal, stones, weight and agreed work.

Warn the client of risks to heat-sensitive or fragile stones before soldering or cleaning.

Sizing down removes a section and re-solders; sizing up inserts metal; both must preserve setting alignment and the hallmark.

Record the solder grade and materials used so future repairs can be planned.

Anneal before forming or bending to avoid cracking work-hardened metal.

Coat the piece with flux or a borax wash before annealing to limit firestain on sterling silver.

Heat to a dull red for silver and gold alloys, hold briefly, then quench or air cool according to alloy.

Pickle after soldering and annealing to remove oxide and flux residues.

Use copper or brass tongs in pickle; steel tongs can plate the work with copper.

Rinse in clean water and dry before polishing to avoid trapping acid in seams.

Finishing sequence: file, abrasive paper coarse to fine, tripoli pre-polish, then rouge or high-colour polish.

Use a separate mop for each compound to avoid cross-contamination.

Burnishing with steel or agate compresses the surface and improves reflectivity without removing metal.

Matte and satin finishes are produced with abrasive paper, a bristle brush or pumice.

Apply matte finishes before final assembly of stones to avoid damaging them.

Clean polishing compound from the piece with ultrasonic or detergent before delivery.

Use separate tools and mops for base metals and precious metals to avoid cross-contamination.

Keep a clean bench to avoid scratches and contamination of polished work.

Collect polishing dust because it contains precious metal and is a health hazard.

Store pickle and plating solutions in labelled containers and neutralise spills with bicarbonate.

Secure gas cylinders upright with flashback arrestors fitted on the torch lines.

Keep a suitable fire extinguisher within reach of the soldering bench.