Hp Self Drilling Screw Sizes Chart Selection Guide | Hebei Wotu Fastener Manufacturing Co., Ltd.
An HP self-drilling screw sizes chart is useful only when its dimensions match the actual assembly. Check the screw diameter and length alongside the material stack, head style, washer or sealing requirement, and drill-point design before selecting a size for roofing, sheet-metal, cladding, or other metal-fixing work.
The main benefit of a correct size is a secure connection without excessive penetration, poor thread engagement, or damage to the supporting material. Treat the chart as a starting point, then confirm the product's dimensional standard and intended application with the supplier.
Brand: Hengzuan Surface: blue and white zinc plated Specifications: in stock ST2.9/ST3.5/ST4.2/ST4.8/ST5.5 Chinese national standard full series, complete rod length 13~60mm, supports nonstandard length customization; drilling adapts to steel sheet thickness 2~6mm Packaging: 25kg cartons, whole wooden pallets
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Brand: Hengzuan Surface: Dacromet anti-corrosion coating Specifications: in stock ST5.5/ST6.3 mainstream caliber, rod length 50mm~150mm, extended full range of specifications, supports nonstandard extra long customized, suitable for drilling steel sheet thickness 2~6mm Packaging: 25kg export cartons, full pallets wrapped with film, supports neutral export packaging, private-label customization
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Brand: Hengzuan Surface: blue and white zinc plated, optional color zinc plated, black oxide treatment Specifications: in stock ST3.5/ST4.2/ST4.8 mainstream specifications, rod length 16~50mm full size range, supports nonstandard length customization, suitable for drilling steel sheets 2~5mm Packaging: 25kg cartons, full pallets packed on wooden pallets, support neutral packaging, private-label customization
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Brand: Hengzuan Surface: high temperature black phosphated anti-rust treatment, blue zinc, color zinc plated coating can be replaced as needed Specifications: in stock ST3.5/ST4.2/ST4.8 common specifications, rod length 16mm~50mm, complete, supports nonstandard size customization, suitable for drilling steel sheets 2~5mm Packaging: 25kg cartons, whole wooden pallets, support neutral packaging, private-label customization
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Brand: Hengzuan Surface: screw color zinc plated + hex head outdoor paint Specifications: ST5.5, ST6.3, rod length 25mm～120mm in stock, supports nonstandard customization, suitable for drilling steel sheets 2～5mm Packaging: 25kg cartons, whole wooden pallets
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Brand: Hengzuan Surface: blue and white zinc plated, color zinc plated can be customized on request Specifications: in stock 4.2/4.8/5.5/6.3mm mainstream wire diameter, length 20mm~165mm full range of specifications, nonstandard rod length, drill point size can be customized Packaging: 25kg export cartons, full pallets wrapped with film, supports neutral export packaging, customer private-label customization
Read MoreHP screw selection points
When reviewing an HP self-drilling screw, compare diameter, length measurement, drill-point design, thread form, head and washer configuration, finish, and substrate suitability. A supplier should also clarify which dimensions are nominal and which are controlled for production or inspection.
| Criterion | What To Check | Why It Matters | Buyer Tip |
|---|---|---|---|
| Confirm what “HP” identifies | Ask the supplier to define the HP designation and provide the matching drawing or part reference. | The abbreviation may describe a head, point, or product series; assuming its meaning can lead to the wrong screw type. | Write the required HP reference exactly as shown on the supplier’s drawing or sample. |
| Compare screw diameter and length | Verify the stated diameter and how length is measured, especially for a pan, hex, or washer-head screw. | Diameter affects thread engagement and holding strength, while usable length depends on the head design and material stack. | Give the total material thickness and specify whether the required length is measured from under the head. |
| Match the drill-point capacity to the joint | Ask which metal thickness range the drill point is intended to penetrate and request a suitable point profile. | A point that is too small may not pierce the outer sheet; one that is unsuitable can waste time or damage the joint. | State the number of metal layers, their thicknesses, and whether insulation or a gap is present. |
| Check head, drive, and washer details | Confirm the head shape, drive type, washer or sealing arrangement, and compatible installation bit. | These details control access, seating, pull-through resistance, and weather sealing at the fastening point. | Send a joint photo or assembly drawing if the screw must sit flush, seal an overlap, or fit restricted access. |
| Verify thread form and finish | Ask for the thread type, intended base materials, coating or plating, and any compatibility guidance for the application. | Thread geometry and surface finish affect grip, corrosion behavior, and the risk of damaging mating materials. | Describe the base metal, indoor or outdoor exposure, and any contact with dissimilar metals before selecting from the size chart. |
The most important distinction is between screw length and usable fastening length. Overall length may include the head, while the working portion must pass through the attached material and still form reliable threads in the supporting section. A longer screw is not automatically better: excess penetration can interfere with the assembly or create an unsuitable exposed point.
Also confirm what “HP” means in the relevant product range. It may identify a series, design, or application rather than a universal sizing standard. Ask the supplier to identify the exact diameter, length convention, head and washer configuration, drill-point range, and compatible substrate for each chart entry.
Start with the materials and total thickness. State the material being attached, the supporting material, and the combined thickness the screw must pass through. Thin sheet, heavier-gauge steel, wood-backed panels, and pre-drilled assemblies can require different point and thread designs even when the visible screw length appears similar.
Compare the full configuration, not just the size line. A hex washer head, pan head, sealing washer, winged design, or other configuration changes the clamping area, clearance, appearance, and sealing behavior. Check the head diameter, drive type, washer material, and coating alongside the nominal diameter and length.
Match the drill point to the support material. Self-drilling screws are selected partly by the thickness and type of material their point must penetrate. Do not substitute a size from a chart without confirming its drilling range, thread form, and required installation method. For exposed or damp applications, ask whether the stated finish is suitable for the service environment and for contact with the materials being joined.
Send a clear enquiry before ordering. Provide the exact material stack and thickness, intended use, preferred head or washer style, finish or corrosion requirement, and the quantity or packaging basis you need quoted. Request a dimensioned drawing or chart for the proposed HP series so you can compare length measurement, point style, and tolerances consistently.
| Criteria | Importance | Description | Example Options |
|---|---|---|---|
| Diameter and thread engagement | Critical for holding strength and fit | The screw must have enough thread contact in the supporting material without damaging the sheet or leaving weak engagement. Diameter should be matched to the load, material thickness, and hole-forming behavior. | A thin sheet fixed to a metal support may need a different thread form or diameter than a thicker bracket fixed to heavier material. |
| Length measurement convention | Often misunderstood during ordering | Some screw lengths are measured from under the head, while countersunk or special head styles may use a different convention. The usable fastening length must be checked against the full material stack. | Two screws with the same stated length may not give the same penetration if one includes a washer or has a different head design. |
| Drill-point suitability | Essential for self-drilling performance | The point must suit the supporting material and thickness. An unsuitable point can fail to drill cleanly, slow installation, damage threads, or require a different fastener type. | A screw intended for light sheet-metal work should not be assumed suitable for a much thicker steel support without confirming its drilling range. |
| Head and washer configuration | Important for clamping, clearance, and sealing | Hex washer heads, pan heads, sealing washers, and winged designs change how the screw sits on the surface and how force is distributed. The chart size alone does not define the complete fastening behavior. | A metal roof panel may require a sealing washer, while an internal bracket may prioritize clearance or drive access instead. |
| Finish and service environment | Important for durability in exposed or damp applications | Coating choice should match the exposure conditions and the materials being joined. Confirm whether the proposed finish is suitable for indoor, outdoor, damp, or chemically exposed use. | A screw used under cover may have different coating requirements from one used on an exterior panel or near moisture. |
Related Options
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Start with the total thickness of the material being fastened, then allow enough thread engagement in the supporting material. Do not choose length by overall appearance alone, because head style, washer thickness, and the supplier’s length-measurement convention can change the usable fastening length.
No. A self-drilling screw has a drill point that can create its own hole in suitable material, while a self-tapping screw forms or cuts threads but may need a pre-drilled hole. The correct choice depends on the substrate, material thickness, and installation process.
Not always. Similar nominal sizes can perform differently depending on the support material, panel thickness, sealing washer, coating, and drill-point range. A roofing or cladding assembly may also need attention to sealing and exposed corrosion resistance, not just screw diameter and length.
Confirm this with the supplier before ordering. “HP” may refer to a product series, head or point style, application category, or an internal naming convention, so it should not be treated as a universal dimensional standard without a matching drawing or chart.
Send the attached material, supporting material, total thickness, preferred head and washer style, finish requirement, and the working environment. If you already have a sample or drawing, include the nominal diameter, length, thread type, and point style so the proposed size can be compared correctly.
Tell us the material stack and total thickness, the supporting substrate, and the required head, washer, finish, or application so we can clarify the suitable HP screw dimensions.
