Guides · 23 October 2026
Pricing outside processing: anodising, plating and heat treatment
The anodiser quotes A$4.20 a part, so the quote says A$4.20 a part. On a batch of ten the job then loses money on the finish alone, because the supplier's price list had three other lines nobody copied across: a minimum lot charge, a racking fee, and the courier both ways.
What a finisher's price actually contains
Most outside processes, whether anodising, plating, passivation, powder coating or heat treatment, are priced the same way:
- A price per part (or per kilogram, or per square decimetre for some platers).
- A minimum lot charge: below a certain quantity you pay the minimum, not the per-part total.
- A setup or racking fee per lot. Read the price list carefully: sometimes the minimum already includes it, sometimes it is added on top.
- Freight, which the finisher does not quote because you arrange it: out and back, usually per order, not per part.
The supplier's charge for one lot is therefore:
lot charge = max(minimum, price per part × parts) + setup fee
If the minimum includes the setup fee, the setup fee goes inside the brackets instead. Either way, add freight once per order.
A worked example
An aluminium housing, Type III hard anodised. The finisher quotes A$4.20 a part, a A$180 minimum lot charge and a A$35 racking fee on top. A courier run there and back costs A$80. The shop adds 10% manufacturing overhead and prices for a 25% margin on cost.
| Quantity | Anodiser's charge | With freight | Cost per part | In the price per part |
|---|---|---|---|---|
| 10 | A$215.00 | A$295.00 | A$29.50 | A$40.56 |
| 25 | A$215.00 | A$295.00 | A$11.80 | A$16.22 |
| 50 | A$245.00 | A$325.00 | A$6.50 | A$8.94 |
| 100 | A$455.00 | A$535.00 | A$5.35 | A$7.36 |
| 200 | A$875.00 | A$955.00 | A$4.78 | A$6.57 |
Copying A$4.20 straight into the quote, with the same overhead and margin, puts A$5.78 a part in the price. At 200 off that is close enough. At 10 off the finish really costs A$29.50 a part before any margin, and the A$57.80 the buyer pays for it does not cover the A$295 the shop pays out.
The minimum stops mattering above 43 parts (180 ÷ 4.20). Below that every lot costs the same, so it is worth asking the buyer whether a larger batch, or combining with another job going to the same finisher, would suit them.
Good parts or every part started?
Where the process sits in the routing decides how many parts you pay for:
- After final machining (anodising, plating, passivation): you only send parts that passed inspection, so you pay for good parts.
- Before final machining (heat treating blanks before finish grinding or hard turning): every blank you start goes through, including the ones you will scrap later, so you pay for parts started.
Heat treaters often price by weight. Convert it to a per-part price using the weight that goes into the furnace, the blank, not the finished part. Example: 4140 blanks weighing 0.82 kg, hardened and tempered at A$5.50 a kilogram with a A$150 minimum, so A$4.51 a blank. Planning for 97% good parts, 50 good parts need 52 blanks:
| Good parts | Blanks treated | Charge | Per good part |
|---|---|---|---|
| 20 | 21 | A$150.00 (minimum) | A$7.50 |
| 50 | 52 | A$234.52 | A$4.69 |
| 100 | 104 | A$469.04 | A$4.69 |
Things the price list will not tell you
- Lead time. A week at the anodiser is a week on the delivery date. Put it in the quote's lead time, not just in your head.
- Handling. Someone degreases, bags, labels, books the courier and checks the parts back in. On small batches that can be half an hour; count it as labour on the job.
- Rework. If a plating defect means re-machining or stripping and re-plating, who pays? Know the supplier's terms before you quote a tight cosmetic finish.
- Masking. Threads, bores and contact faces that must stay bare are often charged extra per part. Ask with the drawing, not after.
- Price dates. Finishers change prices with chemical and energy costs. Note when each price was quoted and ask again when it is old.
Overhead and margin on bought-in work
Some shops pass outside processing through at cost. That is a choice, but it is rarely free: the shop carries the risk of the supplier's defects, the late delivery, and the cash between paying the finisher and being paid by the buyer. Treating it like any other cost on the job, with the same overhead and margin, is the simpler rule, and it is what the example above does.
In Spindlewise each outside process on a part is its own row: supplier, price per part, minimum lot charge, setup fee, whether the minimum already includes the setup fee, and whether it is charged on good or started parts. The lot charge is worked out for every quantity break, a missing supplier price stops the quote instead of counting as zero, and won jobs show the supplier and operation on the buy list.