Keeping Die Codes Straight Across Reorders

The third reorder is where screw plants lose money on tooling. The first order comes with an engineer's attention, a drawing and a trial run. The second is placed against the first. The third is placed by someone who was not there, against a purchase order that says "same as last time" — and by then the wire supplier has changed, the die style was quietly adjusted during the second run, and the person who knew both facts has moved on. Good drill point die reorder record keeping and disciplined die code management is unglamorous work, and it is the difference between a tool that drops in and a tool that arrives correct to a drawing nobody wanted any more.

The failure is rarely dramatic. Nothing snaps. The screws simply drill slower, the point walks on 3 mm plate, drive time creeps past what your customer's specification allows, and the plant burns three weeks arguing with a supplier who built exactly what was asked for.

A die code is a reference, not a record

Series codes exist to stop this. A well-built L-series system — ZLD publishes L1 through L7 — maps every die code to a screw size across IFI #4–#14 and DIN ST2.9–ST6.3, and behind each code sit the dimensional fields that define the tool: drill diameter Dø, point diameter, wire diameter, flute length and die style. That is a genuinely useful spine, and it is more than many die makers publish. It is still not a reorder record.

The reason is that a die code describes the tool. A reorder has to reproduce a result — a specific point, on a specific screw, made on a specific machine, from a specific wire. Half the variables that decide whether the reorder works live on your side of the transaction and appear nowhere in the supplier's code:

• The machine and the die holder. The same code in a different cassette bore seats differently and wears asymmetrically.
• The wire. Grade, tensile class, supplier and diameter tolerance. A die cut for one wire diameter and run on another is the single most common cause of a "wrong" die that is dimensionally correct.
• The screw drawing revision. Point length and drill diameter get adjusted for a customer and the die never gets re-specified.
• The die style. MA, MB and MC describe different point forms. A code plus a size, without the style letter, is ambiguous.
• What the last set actually did. Sets consumed, screws per set, and the failure mode that ended it. Without that, you cannot tell whether a reorder underperformed or whether the last one over-performed.

The minimum record a plant should hold, per die code

One row per die code, held by the plant, not by the supplier and not by the machine dealer. Twelve fields is enough. Fewer than these and you are relying on someone's memory.

None of that needs software. A spreadsheet with twelve columns and one row per code, kept where the tool crib and purchasing can both open it, does the job. What it must not be is twelve fields spread across an ERP part master, an engineer's laptop and a supplier's WeChat thread.

Three details that decide whether the record survives contact with reality

Record the wire, not just the die. Wire diameter is a field on the die chart, which means the die was cut for a specific incoming wire. If procurement re-sources wire on price, the tooling record has silently expired. Put the wire certificate reference in the die row, and make a wire change trigger a tooling review the same way a drawing change does.

Distinguish "build to drawing" from "build to this old die". Both are legitimate inputs — ZLD publishes both routes, taking either a drawing or photographs of the screw or the old die. They produce different tools. A die copied from a worn tool reproduces the worn geometry, which is sometimes exactly what you want if the line has been tuned around it, and is a slow disaster if it is not. Write the instruction explicitly on every purchase order. "Same as last time" does not specify which.

Keep die pairs as pairs. Point dies work as matched sets. A record that counts "6 dies" instead of "3 sets" eventually puts two halves from different builds into one holder, and the resulting point is out of round in a way that inspection at the screw level catches only after several thousand pieces.

Where records break, and what to do about each

The drawing lives in the supplier's file. Extremely common for custom dies developed collaboratively. The supplier engineered the tool, so the supplier holds the master. That is workable right up until you want a second source, or the supplier's engineer changes. Ask for the drawing as a PDF and, where the supplier will provide it, a DXF, and ask what the retention terms are. ZLD does not publish whether it retains customer drawings or for how long — that is a question for the purchase agreement, not an assumption. The broader question of who owns a design developed jointly is covered well in the CMH guide to protecting IP with a Chinese factory; tooling is one of the sharper cases, because the drawing and the physical tool are both in the supplier's hands.

The purchase order says "repeat". A repeat purchase order should still carry the full identifier: supplier die code, style letter, screw drawing revision, material and coating, and the instruction on drawing-versus-sample. Ten extra words on the purchase order line. This is the same discipline that makes a second order to any China supplier land like the first — the specification travels with the order, not in someone's head.

Nobody validated the incoming set. Ask for the supplier's pre-shipment evidence and keep it against the code. ZLD states it runs dies on in-house test equipment before shipment to confirm drilling performance; if you are getting that, ask for what it showed and on what wire, and file it in the die row. Then do your own first-article check on the machine the tool is actually going into.

The specification was never written down properly in the first place. If your original die enquiry was a photograph and a phone call, the record starts empty. Rebuilding it costs one careful specification round — the same structure as any good product spec sheet sent to a Chinese factory, applied to tooling.

Setting this up in an afternoon

1. List the codes you actually reorder. Most plants have between six and fifteen that repeat. Start there, not with the whole crib.
2. Pull the last purchase order for each and copy across the supplier code, style, material, price and lead time.
3. Match each to a screw drawing number and revision. Any code you cannot match is your highest-risk tool — flag it.
4. Find the master baseline. Drawing on file, screw sample in the cabinet, or old die on the shelf. Write down which, and where.
5. Add the wire certificate reference in force today, and note whether it is the same wire the die was originally cut for.
6. Ask each supplier for the drawing and the retention terms in one message. Send it once, to everyone, this week.
7. Amend the purchase order template so the die line has fields for style letter, drawing revision, material and build-to instruction.
8. Log consumption from now on — sets issued, screws produced, failure mode at retirement. Three data points per set. In a year it is the most valuable tooling document in the building.

Common questions

Is the supplier's die code enough to reorder on?

For a catalogue size on an unchanged line, usually yes — a series code that maps to a screw size and carries a style letter is a solid reference. It stops being enough the moment anything on your side has changed: machine, wire, screw drawing, or point spec agreed with your own customer. The code identifies the tool; it does not certify that the tool is still the right one.

How long should a die maker keep my drawing?

There is no standard, which is why it belongs in the contract rather than in an assumption. Ask for a stated retention period, ask whether the file is destroyed or returned at the end of it, and ask who may see it. ZLD's terms on this are not published — treat that as an open item to close, not as a red flag, and see the CMH list of documents to request before a first order for the wider set.

What if my only baseline is a worn die?

Send it, and say so. A competent die maker will measure it and tell you which dimensions have moved. State explicitly whether you want the tool reproduced as-measured or restored to nominal — that single sentence is the whole difference between two very different reorders.

What to ask your die supplier next

• What exactly does your die code encode, and what does it leave to the drawing?
• Will you send me the die drawing as PDF and DXF, and under what terms?
• How long do you retain my drawing, and who owns the design of a tool built to my print?
• Is your code marked on the tool body, or only on the packing list?
• On a reorder, will you build to the drawing on file or to the sample I return — and which is your default if I do not say?
• What pre-shipment run record will come with the set, and on what wire was it run?
• If I change wire grade or diameter, which dimensions on this die would you want to revisit?

A long supplier relationship does not remove the need for any of this; it only changes who remembers. ZLD reports a longest customer relationship of over seven years with uninterrupted reorders — the company's own figure — and plants that achieve that kind of continuity are generally the ones holding their own tooling records, because engineers on both sides eventually move on. Those seven questions take one email and permanently change how a reorder behaves. ZLD Precision Mold is a reasonable place to test them, since its published L1–L7 chart already ties each code to a screw size, a die style and the five dimensional fields you would want in your own record — the ZLD Precision Mold factory profile lays out the stated terms and the questions still open. Whichever die maker you use, the record belongs to your plant, and it should be complete enough that the person placing the fifth reorder never needs to phone the person who placed the first.