Back to Self Tapping Screws

CSK Head Self Tapping Screw

DIN 7982 C  /  ISO 7050  ·  Phillips Cross Drive  ·  White Zinc & Stainless Steel  ·  ST2.9 to ST6.3

The CSK (countersunk) head self tapping screw confirming to DIN 7982 C / ISO 7050 is a fully threaded fastener with a cross recessed Phillips drive and a gimlet point that cuts its own thread into pre-drilled sheet metal, plastic, fibre glass and wood — no nut, no pre-tapped hole required. The flat, conical head seats flush with the material surface when driven into a countersunk hole, giving a smooth, snag-free finish. Excel Trading Corporation stocks this in mild steel white zinc plated and stainless steel SS304 (A2).

Specifications

  • Bullet Icon Standard: DIN 7982 Form C / ISO 7050
  • Bullet Icon Drive: Phillips cross recess (PH)
  • Bullet Icon Point: Gimlet point — Form C (sharp)
  • Bullet Icon Thread: ISO 1478 — fully threaded, coarse pitch
  • Bullet Icon Material: Mild steel white zinc plated & Stainless steel A2 (SS304)

Applications

  • Bullet Icon Flush-fit sheet metal panels and enclosures
  • Bullet Icon Furniture fittings and knock-down furniture assembly
  • Bullet Icon Plastic panels, switch plates and junction box covers
  • Bullet Icon Door and window frame fittings requiring a flat finish
  • Bullet Icon Automotive trim panels and interior fixtures
CSK Head Self Tapping Screws

Available In

Steel

White Zinc

Stainless Steel

Stainless Steel

Available Sizes — DIN 7982 C / ISO 7050

All sizes below are stocked in mild steel white zinc plated and stainless steel SS304 (A2). Countersink the pilot hole to match the head angle so the screw seats flush — refer to the recommended pilot hole column for the hole diameter itself. Use the smallest pilot hole that allows clean installation for maximum thread engagement.

Size (ST) Outer Ø (mm) Head Ø (mm) CSK Depth (mm) Pilot Hole (mm) Common Lengths (mm)
ST 2.9 2.9 5.5 1.7 2.2 6.5  ·  9.5  ·  13  ·  16
ST 3.5 3.5 6.8 2.1 2.7 9.5  ·  13  ·  16  ·  19  ·  25
ST 4.2 4.2 8.1 2.5 3.2 9.5  ·  13  ·  16  ·  19  ·  25  ·  32  ·  38
ST 4.8 4.8 9.5 3.0 3.7 9.5  ·  13  ·  16  ·  19  ·  25  ·  32  ·  38  ·  45
ST 5.5 5.5 10.8 3.4 4.3 13  ·  19  ·  25  ·  32  ·  38  ·  45
ST 6.3 6.3 12.4 3.8 5.0 16  ·  19  ·  25  ·  32  ·  38  ·  45  ·  50

Material Options

Mild Steel — White Zinc Plated

Case Hardened · ISO 2702 · Standard Grade

Case hardened low carbon steel with bright white zinc plating. The hardened thread cuts cleanly through sheet metal, plastic and composite board on the first drive. Zinc plating provides corrosion protection for indoor and dry environments. The most economical choice for general sheet metal fabrication, furniture fittings and switchboard assembly.

Best for: Sheet metal · Furniture fittings · Plastic enclosures · Switchboards · General fabrication

Stainless Steel — A2 / SS304

DIN EN ISO 3506 · A2-70 · Passivated

304-grade austenitic stainless steel (A2), passivated finish. Fully corrosion resistant for outdoor, coastal, humid and marine environments. Non-magnetic, aesthetically clean finish that suits the flush-fit look of a CSK head. Slightly softer than hardened mild steel so should not be driven into very hard substrates. SS316 (A4) available on request for aggressive chemical environments.

Best for: Outdoor enclosures · Coastal installations · Food equipment · Marine panels · Signage

Which Material Should You Choose?

Click your environment to get the right recommendation.

Quick Specifications

ST2.9–6.3

Size Range

DIN 7982

Standard (= ISO 7050)

Phillips

Drive Type

MS + SS

Materials Available

Installation Tips

  • ▸ Always drill a pilot hole — never drive a self tapping screw into undrilled material. An undersized pilot creates excessive torque and risks cam-out or head stripping.
  • ▸ Countersink the pilot hole to match the head angle so the CSK head seats flush — skipping this step leaves the head proud or cracks brittle materials around the hole.
  • ▸ Use the correct pilot hole size from the table above — too large reduces thread engagement; too small risks splitting plastic or snapping the screw.
  • ▸ Do not overtighten — driving a CSK screw too far below flush weakens its grip and can strip the drive recess. Stop as soon as the head sits level with the surface.

Frequently Asked Questions

What is a CSK (countersunk) head self tapping screw?

A CSK head self tapping screw has a flat, conical head that sits flush with or slightly below the material surface once driven into a countersunk hole. The self tapping thread cuts its own thread into a pre-drilled hole in sheet metal, plastic, fibre glass or wood — no nut or tapping tool required. Use it wherever a projecting head would snag, look untidy or interfere with a mating surface. Standardised under DIN 7982 and ISO 7050 with Phillips cross drive.

What is the difference between DIN 7982 C and ISO 7050?

DIN 7982 Form C is the German standard and ISO 7050 is the international equivalent for the same countersunk cross recessed self tapping screw with a sharp thread-cutting point. Dimensions, thread form (ISO 1478) and head geometry are identical — they are interchangeable. Both designations are widely used and accepted in India. Excel Trading Corporation stocks screws compliant with both standards.

Do I need to countersink the hole, and what pilot hole size do I use?

Yes — countersink (chamfer) the pilot hole to match the head angle so the screw sits flush; skipping this leaves the head proud or can crack brittle materials. For the pilot hole diameter itself, refer to the Pilot Hole column in the size table above — the same core-diameter pilot sizes apply as for other head styles since sizing depends on thread diameter, not head shape. Use a slightly smaller pilot in plastic or wood for better thread engagement.

When should I use stainless steel instead of mild steel?

Use stainless steel (A2/SS304) whenever the screw will be exposed to moisture, outdoor conditions, coastal air or food contact. Zinc plated mild steel corrodes over time in these environments — the zinc layer is not sufficient for prolonged wet exposure. For aggressive chemical environments, request SS316 (A4). For all indoor, dry and sheltered applications, zinc plated mild steel is the correct and more economical choice.

Where can I buy DIN 7982 CSK self tapping screws in Bangalore?

Excel Trading Corporation stocks DIN 7982 C / ISO 7050 CSK head self tapping screws in mild steel white zinc plated and stainless steel SS304 at our Kumbarpet store in Bengaluru. We supply sheet metal fabricators, furniture manufacturers, switchboard assemblers and general industry across Karnataka and India-wide. Call +91-9448239476 or email info@exceltrading.in for pricing and availability.