Your customer's purchase specification says the screws must meet IFI 113. You forward that line to your die maker, and nothing happens — because IFI 113 self-drilling screw point requirements govern a finished fastener, not a piece of tooling. No die maker anywhere is certified to a screw standard, and none should claim to be. The standard sits on your side of the fence. Translating it into a die drawing is your job, and if you do not do it, the die you receive will be correct against the drawing you sent and wrong against the standard your customer will test to.
That translation is not difficult, but it is specific. A screw standard fixes three things that the point-forming die has to deliver, and a long list of things it does not. Getting the boundary right is what keeps a failed incoming inspection from turning into a six-week argument between you and a tooling supplier who did exactly what you asked.
What the standard actually specifies — and what it doesn't
The inch-series self-drilling tapping screw documents a US buyer is likely to see named are IFI 113, the Industrial Fasteners Institute standard for self-drilling tapping screws; SAE J78, the long-standing steel self-drilling tapping screw specification; and ASME B18.6.4, the broader inch-series tapping screw dimensional standard. Editions and revision dates move, and specifications written in construction supply chains are frequently marked up rather than invoked whole. Read the current text before you write it into a die RFQ, and confirm with your customer which edition they are testing against — treat every standard number in this article as a pointer, not as a citation.
What all of these documents have in common is their subject: the completed screw. They fix dimensions across the head, the drive, the thread and the point; they fix material and hardness requirements including surface and core hardness and case depth; and they fix performance requirements measured on the finished, heat-treated screw — torsional strength, and a drilling performance test.
Three of those requirements are governed by the point, and therefore by the point-forming die:
Drill point dimensions. The standard gives, per nominal size, the dimensions of the drilling point: the drill diameter, the point length, and limits on how the point relates to the thread. The drill diameter is the one that decides everything downstream — it must be large enough to cut a hole the thread can bite in without stripping and small enough that the thread actually engages rather than spinning free.
Drilling capacity. The standard states, per size, a range of steel thickness the screw must be able to drill through. It is a range, not a maximum: there is a minimum thickness as well, because a point that has not finished drilling before the thread reaches the sheet will jack the sheet or shear the point.
The drill-drive test. The screw must penetrate a steel test plate of stated thickness and hardness, under a stated load, within a stated number of seconds. It is a timed test, run at a stated speed, and it is the requirement most often failed on incoming inspection because it is a single number that either passes or does not.
Everything else in the standard — head dimensions, drive recess, thread form, plating, core hardness, case depth, torsional strength — is fixed by other tooling and other processes. Say this out loud in your own plant, because it decides where you look when a lot fails.
Which requirement maps to which die feature
The die a screw plant orders is normally described by a small set of dimensions. In a die maker's own selection system those columns are typically drill diameter (Dø), point diameter, wire diameter, flute length and die style. ZLD's published L1–L7 series, for example, maps each die code to a screw size in IFI #4–#14 and DIN ST2.9–ST6.3 against exactly those fields. That is convenient, because it is close to a one-to-one mapping onto the standard's point requirements.
| Standard requirement | What it fixes on the finished screw | Die feature that delivers it | Who owns the failure |
|---|---|---|---|
| Drill point diameter, per size | Hole size cut in the work | Drill diameter (Dø) in the die cavity | Die maker, if out of drawing; you, if the drawing was wrong |
| Point length / unthreaded point length | Whether drilling completes before thread engagement | Point geometry and flute length | Shared — spec and tooling |
| Drilling capacity range (min–max steel thickness) | Application envelope of the screw | Flute length and point style, at the specified Dø | You — the spec must state the thickness range you sell into |
| Drill-drive time on the test plate | Pass/fail on incoming inspection | Point geometry, flute geometry, cutting edge condition, surface finish of the die | Shared, and the hardest to attribute |
| Torsional strength | Screw survives the drive | Heat treatment and core hardness of the screw | Screw plant — outside the die entirely |
| Surface hardness and case depth | Point stays hard enough to cut | Heat treat and carburising cycle | Screw plant — outside the die entirely |
| Head, drive recess, thread form | Dimensional conformance | Header punch and die, thread rolling dies | Different tooling, different supplier line |
The row that generates the most disputes is drill-drive time, because it is genuinely shared. A die can be dimensionally perfect and still produce a point that drills slowly because the flute geometry evacuates chips badly, or because the die's surface finish is leaving a rough cutting edge. Equally, a perfect point on an under-hardened screw will fail the same test. Before you send a failed sample back to the die maker, section a screw and check the hardness — you will halve the number of tooling disputes you have.
The drilling capacity minimum is a real constraint, not a formality. Buyers routinely quote a maximum steel thickness to their die maker and leave the minimum blank. If the same screw is also sold into thin sheet, a long point that has not finished cutting when the thread arrives will lift the sheet or snap. If your product ships into both a 1 mm envelope and a 5 mm envelope, that is two point configurations, not one die with a wide tolerance.
Test plate hardness matters as much as thickness. The drill-drive test is specified against a plate of stated thickness and hardness. Plants that build their own incoming test rig sometimes use whatever plate stock is on the shelf. A harder plate at the same thickness will fail points that pass the standard's test, and you will chase a tooling problem that does not exist. Buy plate to the specified condition and keep the mill certificate with the test records.
The die is consumable and drifts before it breaks. Point geometry is measured against the drawing when a die is new. As the cavity wears, the drill diameter and the cutting edges move, and the screw's drill-drive time gets longer while every dimension is still nominally in tolerance. Plot drill-drive time by die-life hours, not just by lot. The curve tells you when to change tooling long before a lot fails.
Turning the standard into a die RFQ
A die maker who has never read IFI 113 will build accurately to whatever you send. So send the derived requirements, not the standard number. A workable sequence:
- Fix the screw size in the standard's own designation. Nominal size, thread, point type, per the edition your customer names.
- Read out the point requirements from the standard's tables. Drill diameter and its tolerance, point length, drilling capacity range, drill-drive time limit and its test conditions. Write these into your own internal spec sheet with the edition and date on it.
- Convert to die-side dimensions. Drill diameter Dø, point diameter, wire diameter, flute length, die style. This is the step no die maker can do for you, because it depends on your wire, your machine and your heat treatment.
- State the machine. Point-forming machine make, model and stroke, so the die body and shank fit without a re-fit.
- State the material intent. High-speed steel or carbide, and whether you want a coating — driven by run length and screw material, not by price alone.
- Send a physical reference. A drawing, a bag of current-production screws, or the old die. Most die makers accept all three; ZLD's stated eight-step custom program runs drawing or sample in, engineering review, quote, sampling, trial production, adjustment, stable output.
- Ask for a trial run before shipment. Not a dimensional report — an actual drilling run. Ask what plate was used, at what thickness and hardness, and what times were recorded.
- Define acceptance in your own PO. Your incoming test, your plate, your time limit, and what happens if the first sample misses. Put it in the purchase order rather than in email.
For the wider discipline of writing a spec a Chinese supplier can actually build to, how to write a product spec sheet for a Chinese factory covers the format; the point-geometry fields themselves are unpacked in point geometry for self-drilling screws, and the mapping from die code to screw size in reading an L1–L7 drill point die chart.
The conformance boundary, stated plainly
No drill point die maker conforms to IFI 113, and you should be wary of one that says it does. The standard has no provision for tooling conformity; it specifies a fastener and the tests that fastener must pass. What a die maker can be held to is your drawing, your dimensional tolerances, and a trial run that demonstrates the die produces a point that drills.
That distinction matters when you are evaluating suppliers, because it tells you what evidence is worth asking for. A certificate is the wrong ask. A dimensional inspection report against your drawing, plus a recorded pre-shipment drilling trial, is the right one. ZLD, for instance, states it currently holds no quality-system or inspection certificates, and its published capability on this point is in-house test equipment used to trial-run dies before shipment — which, for a die buyer, is the more useful of the two. Ask for the trial-run evidence; then verify it yourself on your own line. The general approach to evidence before shipment is covered in product inspection in China before shipment.
Common questions
Does buying a die "for IFI #10" mean my screws will meet the standard?
No. The size designation tells you which family of dimensions the die was built around. Conformance is decided on the finished screw, after threading, heat treatment and plating, on the standard's own tests. A correctly sized die is a precondition, not a guarantee.
My screws fail drill-drive time. Is that the die?
Sometimes. Check three things in order before you blame tooling: core and surface hardness of the failing screws, the hardness and thickness of your test plate, and the hours on the die. Only when all three are clean is the geometry the likely cause — and then the useful evidence is a section of the point compared against the drawing.
Can a die maker quote from a standard number alone?
Not usefully. The standard fixes the screw; it does not fix the die cavity, the die body, the material or the fit to your machine. Expect a competent supplier to come back asking for the machine model and a sample — that question is a good sign, not a delay.
How do IFI and DIN sizes interact if I sell into both markets?
They are two entry points into the same tooling range, but the dimensional requirements behind them differ and the near-equivalents are not interchangeable. Treat them as separate configurations and confirm the actual drill diameter for each rather than substituting by size label.
What should be in the purchase order beyond dimensions?
Acceptance criteria, expressed as your test rather than the supplier's: plate thickness and hardness, drive speed and load, time limit, sample size, and the remedy if the first sampling misses. Sampling on a standard die typically runs a few days, so a defined adjustment loop costs you far less than an undefined one.
What to ask the supplier next
Before you place a first die order against a standards-driven screw program:
- Send the derived point dimensions, not the standard number — Dø and tolerance, point diameter, wire diameter, flute length, die style, plus your machine model.
- Ask what the supplier will trial-run before shipment, on what plate, and whether the recorded times come with the die.
- Ask what happens on a miss — how many adjustment loops are included in the price, and how long each takes.
- Ask for the die code to be etched and recorded, so a reorder in two years reproduces the same geometry rather than a fresh interpretation.
- Start with one set. A single-set trial against your own drill-drive test tells you more about a die supplier than any document exchange.
ZLD Precision Mold is a Dongguan die maker whose L1–L7 selection system is published against IFI #4–#14 and DIN ST2.9–ST6.3 sizes with the drill-diameter, point-diameter, wire-diameter, flute-length and die-style columns filled in, and whose stated terms include standard samples in three to four days and trial orders from a single set. That combination — a chart in your size language, and a small first commitment — is what makes a standards-driven translation testable before it becomes a program. For the broader sourcing context around fastener supply chains, see industrial fasteners sourcing in China.