A customer receives a 100-piece order of silver bands, and at 3x magnification half of them carry faint diagonal lines that no amount of rouge removed. The polisher did not skip a step — the bench hand did. The scratch pattern was set at the 220-grit stage and never fully cut out. Surface prep on jewelry is a grit-by-grit chain, and every stage must erase the one before it before you move on. Here is the chain our bench follows from the moment a casting comes off the sprue.
Stage 1: sprue removal and draw filing
The piece comes off the tree with a sprue nub left on the back. We cut the nub flush with a jeweler's saw, then take a flat or half-round hand file (typically a #2 cut, which is medium-coarse) and lay long, parallel strokes along the contour. This is the only stage where a deep scratch is acceptable — we are removing 0.3–0.5 mm of metal to even the surface. We never file crosswise because cross scratches are the hardest to remove later. The broader finishing sequence is described in polishing compounds and finishing stages.
Stage 2: 220 to 400 grit
Next we move to abrasive paper. We start at 220 grit on a stick or a flexible shaft drum, working the whole surface in one direction until every file mark is gone. Only then do we step to 320, then 400. The rule on the bench is simple: do not move up a grit number until you have inspected the surface under a 3x loupe and cannot find a single 220 line. Jumping from 220 straight to 600 is the classic shortcut that buries deep scratches under a bright buff. Abrasive grit itself is explained in the sandpaper reference on Wikipedia.
Stage 3: 600 and 800 grit, and flex-shaft prep
At 600 grit we switch to a different tool: a flexible shaft with a rubber or silicone abrasive wheel, and for tight corners a small barrel-shaped bristle brush loaded with 600-grit compound. Prongs, filigree gaps, and inside shanks get brushed by hand because paper will not reach. We finish this stage at 800 grit on visible flat surfaces. At this point the piece looks matte and even — no gloss yet. The hand work we do at this stage is compared against machine options in hand polishing vs mass finishing, and the barrel route for simpler pieces is in barrel finishing vs hand polishing.
Stage 4: before the buff
Right before tripoli rouge, we take a minute to inspect every piece under the bench microscope. We look for file marks left inside prong baskets, for a scratch on the bezel interior, or for a porosity pit the file opened up. Anything found goes back one grit stage, not straight to the buff. Roughness after this prep is typically Ra 0.3–0.5 micrometers; the buff takes it down to Ra under 0.15. The same inspection habit is part of our outgoing check in jewelry order QC checklist.
Time and cost per stage
A simple silver band spends about 90 seconds at 220 grit, 60 seconds at 400, and 45 seconds at 600 on the flex shaft, plus a minute of hand-brushing inside the shank. Add sprue off and draw filing and the bench prep runs 4–6 minutes per band, which on a 500-piece order is about 40 hours of bench time. Skipping a grit stage saves 60 seconds a piece but adds roughly 3 percent to the reject rate at final QC, because scratches that survive to the buff cannot be fixed. On a pavé ring the numbers double: 12–15 minutes per piece, most of it spent brushing the stone seats by hand. We price bench prep as a separate line on the quote so buyers can see where the time goes.
What grit removes file marks fastest?
A 220-grit paper on a rigid stick cuts a #2 file mark in about 30 seconds of steady pressure. Going finer than that at this stage wastes time.
Can I skip 400 grit and go 320 to 600?
Sometimes, on a smooth casting. But on a heavy piece with a deep draw-file stage, 320 lines survive into the buff and show up as swirls. We keep 400 as a safety step on anything over 5 grams.
Do you use files on gold the same way?
Yes, but gold clogs files faster. We use file wash (a brass brush) every few strokes and step down one grit size earlier than we would on silver.
How long does prep take per ring?
A simple band takes 4–6 minutes from sprue off to buff ready. A pavé setting takes 12–15 minutes because every seat gap has to be brushed by hand.
Send us a sample for a finishing-spec match. HOLYCOME runs bench prep, buffing, and plating in-house — ask about our custom manufacturing program and send a reference piece whose finish you want matched, and we will quote the grit and buff stages to hit it.
Frequently Asked Questions
How do I verify a factory before placing a bulk order?
Request a production video, business license, export records and a paid sample run. A factory that accepts a 50-piece test order is usually a real manufacturer.
What payment terms do you offer?
30% T/T deposit with the balance against the bill of lading. This protects both sides on first orders and can move to net terms after a track record.
What is your normal reject rate?
3–5% under 10x loupe inspection for cast and set pieces. Defective units are replaced free in the next shipment.
Where is the factory located?
Wuzhou, Guangxi, China—the core lab-grown and moissanite manufacturing cluster. Shipments go via Guangzhou or Shenzhen ports.
