A buyer received a reorder of 500 bands and noticed some rings felt noticeably lighter than the approved sample. The supplier's invoice said same weight. But nobody had written a tolerance, so same meant whatever the day's pour produced. Weight drift is not a cosmetic issue; it is a process signal. When finished rings vary more than a defined band, something in the alloy, gating, or polishing is moving, and the buyer should know before retail customers feel it. Measuring weight and tolerance properly is how wholesale QC works.
How weight is actually measured
Finished rings are weighed on a precision balance accurate to 0.01 grams, after all stones are set and final polishing is complete. Stones contribute a small amount to total weight, so a piece with stones is weighed as a whole rather than comparing only the metal. The target weight comes from the approved sample: that ring is weighed, recorded, and becomes the reference. Every production ring is then weighed against that reference, and the spread is documented. We record weight per piece on the QC sheet, not just an average, because an average hides the 5 percent of rings that came out light.
Tolerance bands are a commercial decision. A standard band might hold target weight within +/- 5 to 10 percent; a high-value piece where price-per-gram matters might tighten to +/- 3 percent. The tighter the tolerance, the more metal the caster must hold back to avoid light pieces, and that cost appears in the price. Buyers should decide which tolerance they actually need rather than defaulting to the supplier's loose default. This connects directly to consistent alloy chemistry, because lot-locked grain pours predictably, while variable alloy shifts density and weight run to run.
What weight drift tells you
If most rings come out light of target, likely causes are: thinner casting from shrinkage not compensated in CAD, over-polishing that removes surface metal, or a lighter alloy package than approved. If rings come out heavy, the caster may have increased wall thickness to avoid casting defects, or the sprue cleanup left extra metal. Either direction matters. A light ring wears faster and feels cheap on the finger; a heavy ring costs the buyer more per gram than priced. Weight spread also correlates with finishing time, because pieces that need extra buffing lose material and land light.
Weight is not the only measurement. Ring size, inner diameter measured with a mandrel or gauge, shank width, and stone seat fit are checked on the same piece. We sample a percentage of each lot for full dimensional checks, size, width, weight, and visual inspection, and 100 percent for high-value or high-tolerance orders. The size check catches shrinkage scaling errors; the weight check catches alloy and finishing drift; together they confirm the process is under control.
What to write into your QC spec
State the target weight from the approved sample, the allowed tolerance, for example +/- 5 percent, whether stones are included in the weight, and what happens to out-of-tolerance pieces: rejected, adjusted, or repriced. Require a weight log per lot with the average and the range, not just a pass/fail. For reorders, specify match approved sample weight rather than a number, because the sample is what the buyer signed off. This is also where plating thickness is noted, it adds a small, predictable weight that should be included in the target.
Done right, weight and tolerance data turns into a relationship: every reorder comes back inside the same band, and the buyer can trust that the product on the shelf matches the sample. That consistency is the whole point of wholesale manufacturing.
Density checks are the fastest way to catch a wrong alloy. If a batch of rings comes out structurally correct but systematically light, the balance reading plus a quick XRF tells you whether the caster used a lighter alloy package or simply over-polished. We log both weight and a spot XRF on suspect lots, so a drift in grams is always paired with a drift in metal content. For buyers, this pair of measurements is what turns a vague light-ring complaint into a data-backed correction on the next run. Weight logs are also cross-checked against karat fineness definitions so that a light ring is not confused with an under-karat one.
FAQ
How much weight variation is normal between rings?
A controlled production run holds within about +/- 5 percent of target on simple bands. Beyond +/- 10 percent, the process is drifting and should be investigated.
Should I include stones in the ring weight spec?
Yes, weigh the finished piece as the customer receives it, stones included, so the sample and production comparison are apples to apples.
Why are my reorder rings lighter than the sample?
Usually over-polishing or uncompensated shrinkage. If weight drifts on reorders, request the per-lot weight log and check whether alloy chemistry or finishing changed.
Want weight and tolerance written into your QC? HOLYCOME weighs every finished ring, logs per-lot averages and ranges, and holds reorders to your approved sample. Ask for a custom manufacturing QC sheet.
Frequently Asked Questions
What ring sizes can you supply in bulk?
US sizes 5–12 including half sizes. Send a size breakdown with your order and we cast to that curve; comfort-fit inner bands reduce resize requests.
Can I order a mixed size run instead of one size?
Yes. Mixed runs are standard for wholesale: specify quantity per size and we pack and label by size at no extra labor cost.
What is the MOQ for custom ring designs?
50 pieces per design for existing molds; 100–300 pieces when a new mold or CAD model is required.
How should I price rings for retail margin?
Most partners use a 3–4x markup on FOB cost for sterling and 2.5–3x for moissanite solos, which keeps landed cost under 30% of retail.
