Brass Chips Going Out With the Scrap Dealer: Does the Weight Match What You Machined? (₹)
Does the brass turnings weight your scrap dealer pays for match what your machines cut off? Check it monthly: bar issued, minus good parts, rejects and bar ends, equals the turnings you should have sold. In our worked example, a 3% gap on 12.6 tonnes of turnings is about ₹2.7 lakh a month at an assumed ₹700/kg, below BigMint's ₹810/kg Jamnagar brass honey assessment of 19 June 2026.
Last checked: 17 Oct 2026
By the Mama Editorial Team. Figures carry source and date; our own inputs are marked "assume".
Key takeaways
- Expected turnings are arithmetic, not opinion. Every kilogram of bar issued to the machines leaves as a good part, a reject, a bar end, chips, or stock still on the floor. Weigh four of those and the fifth is known.
- Oil cannot explain a shortfall. The ReMA/ISRI scrap specifications of July 2026 cap yellow brass rod turnings ("Night") at 3% free iron, oil or other moisture. Wet chips weigh more than the brass in them, so oil explains a surplus, never a gap.
- Use the right density. The Copper Development Association lists free-cutting brass C36000 at a specific gravity of 8.5 and copper C11000 at 8.91 (both checked 17 Oct 2026). Using one for the other moves expected part weight by about 5%.
- Grade matters as much as weight. The same specifications list turnings, leaded turnings and rod ends as separate grades. A bag graded as turnings is paid at the turnings rate, rod ends inside it included.
- A camera at the scrap yard shows bags, bins, vehicles and times. It does not show kilograms, oil content or alloy.
Why the scrap dealer's weight deserves a monthly check
In a brass parts shop, the turnings are not waste. They are the second product. On a typical turned fitting, a large part of the bar's weight ends up as chips, and every one of those kilograms goes back to market at a metal price.
Jamnagar is the obvious case. IANS reported on 18 February 2026 that the city has nearly 8,000 brass component units employing over 300,000 people. Machine shops in Rajkot and Ludhiana that turn brass or copper run the same flow.
Typically, turnings go from bins under the machines into bags and to a dealer who weighs them on his own scale. The owner sees a cheque, rarely compared with what the machines cut.
The mass balance: five places a kilogram of bar can go
Write it as one line:
Bar issued = good parts + rejected parts + bar ends + turnings + change in floor stock
Rearranged, the turnings you should have sold are:
Expected turnings = bar issued − good parts − rejected parts − bar ends − increase in floor stock
Each term has a source in the plant:
| Term | Where the number comes from | Unit |
|---|---|---|
| Bar issued | Store issue slips to the machine shop, for the month | kg |
| Good parts | Pieces dispatched or moved to finished store × weighed piece weight | kg |
| Rejected parts | Rejects kept apart and weighed, not counted | kg |
| Bar ends and crop ends | Weighed separately before they go in any bag | kg |
| Floor stock change | Half-machined parts and bar on machines, start vs end of month | kg |
| Expected turnings | Arithmetic from the rows above | kg (dry metal) |
| Sold turnings | Dealer's weighment slips for the same month | kg (as weighed, wet) |
Two rules make the balance honest.
Weigh pieces, do not calculate them. Weigh 20 good pieces per part number monthly and divide. A drawing weight ignores chamfers and threads, and the error multiplies across lakhs of pieces.
Close every term on the same day. Store issues to the 30th against dealer pickups to the 3rd compares two different months.
Densities and bar weights: getting the expected number right
If you do not yet weigh pieces, or you want to check what the bar supplier billed, you need density.
The Copper Development Association's alloy database gives these figures (checked 17 Oct 2026):
| Alloy (CDA number) | Typical use | Density (g/cm³, = specific gravity) | Source |
|---|---|---|---|
| C36000 free-cutting brass: Cu 60.0–63.0%, Pb 2.5–3.0%, Zn remainder | Turned fittings, inserts, valve parts | 8.5 | CDA C36000 |
| C11000 electrolytic tough pitch copper | Lugs, terminals, busbar parts | 8.91 | CDA C11000 |
From that, bar weight per metre is area × density. Round bar area is π/4 × d². Hex bar area is 0.866 × (across flats)².
| Bar (assume) | Cross-section (mm²) | Brass at 8.5 (kg/m) | Copper at 8.91 (kg/m) |
|---|---|---|---|
| 25 mm round | 490.9 | 4.17 | 4.37 |
| 22 mm hex (across flats) | 419.1 | 3.56 | 3.73 |
| 16 mm round | 201.1 | 1.71 | 1.79 |
Two uses. First, weigh a few bars on receipt and compare with the invoice and with this table. Bar sold by weight but shipped light is a gap that shows up later as "missing turnings". Second, copper is about 5% denser than this brass (8.91 ÷ 8.5 = 1.048), so a copper part costed at brass density looks about 5% lighter than it is.
Oil and moisture: why the sold weight should be heavier, not lighter
The ReMA/ISRI Scrap Specifications, July 2026 edition (PDF p. 12) define "Night" yellow brass rod turnings as "not to contain over 3% free iron, oil or other moisture", with tin at most 0.30% and alloyed iron at most 0.15%. The general "Nomad" yellow brass turnings grade carries the same 3% ceiling and is "to be sold subject to sample or analysis". Leaded brass turnings ("Nascent") and new rod ends ("Noble") are separate grades in the same document.
The mass balance gives you dry metal. The dealer's slip gives you metal plus oil plus water. If the chips are wet, the slip should show more than your expected figure.
So:
- Slip above expected: oil and moisture can explain it, up to whatever your chips actually carry.
- Slip below expected: oil makes the real gap bigger. A slip 3% short on wet chips with 3% oil is closer to 6% short in metal.
The exception is time: chips left for weeks in an open yard drain and dry before the dealer weighs them. So weigh your own bags when they are filled.
Measure your own oil content once. Take a 5 kg sample from a full bag, let it drain or spin it, dry it, and weigh it again. The percentage you lose is your number. Repeat after any coolant change.
Worked example: a brass fittings shop, one month
Assume a Jamnagar-style shop turning one family of C36000 brass fittings on sliding-head and CNC machines. All quantities below are assumptions for illustration, not data from any plant.
| Line | Quantity (assume) | kg |
|---|---|---|
| Bar issued from store | 30,000 kg | 30,000 |
| Good parts | 3,90,000 pcs × 41 g (weighed average) | 15,990 |
| Rejected parts (weighed) | — | 370 |
| Bar ends and crop ends (weighed) | — | 1,050 |
| Floor stock change | Same as last month | 0 |
| Expected turnings (dry metal) | 30,000 − 15,990 − 370 − 1,050 | 12,590 |
| Sold turnings on dealer slips | 6 pickups | 12,210 |
| Gap on slip weight | 12,590 − 12,210 | 380 (3.0%) |
Now price it. BigMint assessed brass honey scrap at about ₹8,10,000 a tonne ex-works Jamnagar on 19 June 2026. Oily turnings are a different grade, so assume the dealer pays ₹700/kg for them, ex-GST. Put your own last slip rate in place of this figure.
| Scenario | Gap (kg/month) | ₹ per month at ₹700/kg | ₹ per year |
|---|---|---|---|
| Gap on slip weight, oil ignored | 380 | ₹2,66,000 | ₹31.9 lakh |
| Chips carry 3% oil (12,210 × 0.97 = 11,844 kg dry) | 746 | ₹5,22,200 | ₹62.7 lakh |
| Oil-adjusted gap above an assumed 1% allowance (126 kg) for fines, sump and conveyor loss | 620 | ₹4,34,000 | ₹52.1 lakh |
The last row shows why a tolerance band must be set before you look. Assume you allow 1% of expected turnings for fines in the coolant tank, chips stuck in conveyors and spillage. Anything above that band is a question for the store, the scrap yard and the dealer.
Mini-calc: your own month on one sheet
Fill in the right-hand column from last month's records.
| Step | Formula | Your number |
|---|---|---|
| A. Bar issued (kg) | Store issue slips | |
| B. Good parts (kg) | Pieces × weighed piece weight | |
| C. Rejects (kg) | Weighed | |
| D. Bar ends (kg) | Weighed | |
| E. Floor stock increase (kg) | End minus start | |
| F. Expected turnings, dry (kg) | A − B − C − D − E | |
| G. Your oil and moisture (%) | Your 5 kg drying test | |
| H. Sold turnings, wet (kg) | Dealer slips | |
| I. Sold turnings, dry (kg) | H × (1 − G) | |
| J. Gap (kg) | F − I | |
| K. Gap (%) | J ÷ F | |
| L. Gap (₹/month) | J × your slip rate |
Where a gap usually comes from
The pattern of the gap tells you where to look. These are checks on records and equipment, not findings about any person.
| Pattern | Likely cause | Check |
|---|---|---|
| Same % every month | Piece weight wrong, or bar weight on invoice above actual | Re-weigh 20 pieces; weigh 5 bars on receipt |
| Gap jumps on certain pickups | Weighment at the dealer's scale | Weigh every bag on your own scale before loading; keep the slip next to the dealer's |
| Turnings above expected | Piece weight understated, wet chips, or bar ends in the turnings bags | Drying test; open one bag |
| Bar ends far below the bar count | Rod ends sold inside turnings bags | Count bar ends against bars issued; bag them apart |
| Gap only in months with night pickups | Bags leaving when no one weighs | Fix pickup hours; match gate register to slips |
Grade loss is easy to miss because the weight is honest. The July 2026 ReMA/ISRI specifications list new yellow brass rod ends as their own grade, separate from turnings. Ask the dealer for his rate on each grade, and the difference is what every kilogram of mixed-in rod ends costs you.
For the vehicle and weighbridge side (short weighment, ghost trips, after-hours trucks), see the gate and the weighbridge. For what rejects already cost before they become scrap, see what a 3% rejection rate costs a CNC shop and the rework cost calculator.
What cameras can and cannot tell you here
A camera can show how many bags or drums leave the scrap yard and when, whether each was put on your own scale before loading, which vehicle took them, and whether bins move between bays outside working hours. The layout for that is in the scrap yard CCTV specification.
A camera cannot show kilograms, oil content, alloy or lead content, or whether a bag of turnings has rod ends at the bottom. Weight comes from a scale. Grade comes from opening a bag or from analysis.
A camera cannot replace the balance. Footage of 48 bags leaving means nothing until you know how many kilograms 48 bags should hold. The sheet above is the control; video tells you where to look when the sheet does not close.
The scrap yard also films contract staff and the dealer's driver. Footage of recognisable people is personal data under s.2(t) of the DPDP Act, 2023; tell workers in writing what is recorded and why (see the worker CCTV notice under DPDP).
Where Mama fits
Mama reads the cameras a factory already has and sends the owner a short note each morning on where hours were lost: which machines ran, which stood, and for how long. In a brass shop that gives a second view of the month: machine running time against pieces made, which helps tell a piece-count problem from a scrap-yard problem. Mama watches machines and material flow, not named people. Leave an email or phone in the form below and Mama will get back to you.
FAQ
How do I calculate how much brass scrap my machines should produce? Take bar issued for the month, subtract the weight of good parts, rejected parts and bar ends, and subtract any increase in half-machined stock on the floor. What remains is the dry weight of turnings the machines should have produced. Weigh pieces and bar ends rather than calculating them.
Can coolant or oil in the chips explain why the dealer's weight is lower? No. Oil and water add weight, so wet chips should weigh more than the dry metal your balance predicts. A shortfall on wet chips means the metal gap is larger than the slip shows.
What density should I use for brass and copper parts? The Copper Development Association lists free-cutting brass C36000 at a specific gravity of 8.5 and copper C11000 at 8.91 (checked 17 Oct 2026). Use the figure for your actual alloy, and prefer a weighed sample of 20 finished pieces over any calculation.
What gap between expected and sold turnings is normal? There is no published standard for a machine shop. Set your own band before you look, based on fines in the coolant tank, chips left in conveyors and spillage; this article assumes 1%. A gap that is the same every month usually points to a wrong piece weight; a gap that jumps on certain pickups points to the weighment.
Should rod ends and turnings go in the same bag? No. The ReMA/ISRI specifications list new yellow brass rod ends and yellow brass turnings as separate grades. A bag sold as turnings is paid at the turnings rate, so bag them apart, weigh them apart and ask the dealer for both rates.