IFI Drill Point Die Specifications: Complete Size Reference
Complete IFI (Industrial Fasteners Institute) drill point die specification reference. Size chart from #4 to #14, drill diameters, point lengths, and die series mapping for self-drilling screw production.
IFI Standards for Self-Drilling Screws
The Industrial Fasteners Institute (IFI) sets the North American standard for self-drilling screw dimensions. IFI specifications define the drill point geometry that your dies must produce — making this a critical reference for die purchasing decisions.
This guide covers the practical die specifications for each IFI size, not just the theoretical dimensions.
Note: The "ZLD Die Series" and "Die Codes" referenced below are ZLD Precision Mold's product designations mapped to IFI screw sizes — they are not part of the IFI standard itself. This mapping is provided as a practical purchasing reference.
IFI Size Chart with Die Specifications
Complete Cross-Reference Table
| IFI Size | Nominal Ø (mm) | Metric Equivalent | Thread Pitch (mm) | Drill Ø Range (mm) | ZLD Die Series |
|---|---|---|---|---|---|
| #4 | 2.84 | ~ST 2.9 | 1.06 | 2.2–2.3 | L1 |
| #6 | 3.50 | ~ST 3.5 | 1.27 | 2.7–2.9 | L1 |
| #7 | 3.81 | ~ST 3.9 | 1.27 | 2.9–3.2 | L1 |
| #8 | 4.17 | ~ST 4.2 | 1.27 | 3.1–3.6 | L1–L2 |
| #10 | 4.83 | ~ST 4.8 | 1.59 | 3.7–4.1 | L2–L3 |
| #12 | 5.49 | ~ST 5.5 | 1.59 | 4.2–4.8 | L3–L5 |
| #14 | 6.35 | ~ST 6.3 | 1.59 | 5.0–5.7 | L5–L6 |
Detailed Die Code Mapping
| IFI Size | Available Drill Diameters (mm) | Die Codes |
|---|---|---|
| #4 | 2.2, 2.3 | L1-22, L1-23 |
| #6 | 2.7, 2.8, 2.9 | L1-27, L1-28, L1-29 |
| #7 | 2.9, 3.0, 3.1, 3.2 | L1-29, L1-30, L1-31, L1-32 |
| #8 | 3.3, 3.4, 3.5, 3.6 | L1-33, L1-34, L1-35, L1-36 |
| #10 | 3.7, 3.8, 3.9, 4.0, 4.1 | L1-37, L1-38, L1-39, L1-40, L1-41 |
| #12 | 4.2, 4.3, 4.5, 4.7, 4.9 | L1-42, L1-43, L1-45, L1-47, L1-49 |
| #14 | 5.1, 5.3, 5.5 | L1-51, L1-53, L1-55 |
How to Select the Right Drill Diameter
The correct drill diameter depends on the target material thickness:
Selection Principles
- Drill Ø must be larger than root diameter — creates clearance for thread engagement
- Thicker target material generally calls for a larger drill Ø — more material to remove
- Multiple layers benefit from a larger drill Ø — total stack-up determines requirement
Recommended Drill Diameters by Material Thickness
For IFI #10 (ST 4.8) as example:
These diameter-to-thickness pairings are practical references based on common industry experience. Your optimal selection may differ depending on steel grade, plating, and drive conditions.
| Target Thickness | Recommended Drill Ø | Die Code | Rationale |
|---|---|---|---|
| 0.5–1.0mm | 3.7mm | L1-37 | Minimum clearance, fastest drilling |
| 1.0–2.0mm | 3.8–3.9mm | L1-38, L1-39 | Standard construction range |
| 2.0–3.5mm | 3.9–4.0mm | L1-39, L1-40 | Medium-gauge steel |
| 3.5–5.0mm | 4.0–4.1mm | L1-40, L1-41 | Heavy structural |
Point Length Standards
IFI defines drill point length categories based on drilling capacity:
| Point Type | Symbol | Steel Thickness Capacity | Typical Application |
|---|---|---|---|
| #1 | Short | Up to 0.9mm | Light sheet metal |
| #2 | Medium | 0.9–2.0mm | Standard construction |
| #3 | Long | 2.0–5.0mm | Structural steel |
| #4 | Extra-long | 5.0–8.0mm | Heavy multi-layer |
| #5 | Ultra-long | 8.0–12.5mm | Special applications |
Die implication: Longer point types require dies with deeper flutes and more precise geometry. Points #3 and above are predominantly manufactured in tungsten carbide due to the deeper cavity geometry and higher forming forces involved.
Testing per IFI Standards
Drill Performance Test (per SAE J78)
Self-drilling screws are tested for drill-through performance. The following are typical test parameters and acceptance criteria — actual acceptance should follow the specific standard version and test conditions applicable to your production.
- Typical test setup: Screw driven into steel plate of specified thickness at approximately 2,500 RPM
- Common acceptance criteria:
- Complete penetration within approximately 5 seconds for Point #1–#2
- Complete penetration within approximately 10 seconds for Point #3
- Complete penetration within approximately 15 seconds for Point #4–#5
- No visible point damage or deformation after drilling
These are typical test results — actual performance depends on plate material, hardness, thickness, RPM, applied load, and test standard version. Actual acceptance should follow the specific standard version and test conditions applicable to your production.
Dimensional Inspection
Critical dimensions measured per IFI requirements:
| Dimension | Method | Tolerance |
|---|---|---|
| Drill diameter | Go/no-go gauge or optical | ±0.05mm |
| Point concentricity | V-block + dial indicator | ≤ 0.05mm TIR |
| Flute symmetry | Visual + profile projector | Symmetrical within 10% |
| Point angle | Optical comparator | ±2° |
Common Die Ordering Mistakes
Mistake 1: Ordering by Screw Size Only
"I need dies for #10 screws" is insufficient. You need to specify:
- Drill diameter (3.7mm? 3.9mm? 4.1mm?)
- Point type (#1, #2, #3?)
- Material (tungsten carbide or HSS?)
Mistake 2: Using Same Die for Different Materials
A die optimized for 0.8mm galvanized steel is unlikely to perform well on 3mm structural steel, even if the screw size is the same. The drill diameter and point geometry should match the application.
Mistake 3: Ignoring Plating Thickness
If your screws receive zinc plating (typically +0.008–0.013mm per side), the drill point diameter grows slightly. Factor this into your die selection:
- Before plating: Measure at the die-specified diameter
- After plating: Verify the final diameter still falls within IFI tolerance
Ordering Guide
When ordering drill point dies to IFI specifications, provide:
- IFI screw size (#4 through #14)
- Target drill diameter (in 0.1mm increments)
- Point type (#1 through #5)
- Die material (tungsten carbide / HSS)
- Production volume (helps determine die grade recommendation)
- Header machine model (for die holder compatibility)
Get IFI-Compliant Dies
ZLD Precision Mold manufactures drill point dies for the complete IFI size range (#4–#14). Our specification table maps every IFI size to available die codes and drill diameters.