Stainless Steel Pan Slotted Self Tapping Screw

Choosing the Right SS Pan Slotted Self-Tapping Screw (Guide)
for stainless steel pan head, slotted, self-tapping screws

1. What is an SS Pan Slotted Self-Tapping Screw?

An SS pan slotted self-tapping screw is:

Pan head – slightly rounded top with a flat bearing surface under the head

Slotted drive – single straight slot for a flat screwdriver

Self-tapping thread – forms/cuts its own thread in thin sheet metal or plastics

Stainless steel – corrosion-resistant

It is used to fix thin sheets or components directly into a pre-drilled/punched hole, usually without a nut.

2. When Should You Use It?

Choose SS pan slotted self-tapping screws when:

You are fastening thin sheet metal or plastics

A small, visible, slightly raised head is acceptable

Assembly is done mostly with hand tools (traditional screwdriver)

Load is light to medium (covers, panels, brackets, clamps)

Typical applications:

Electrical junction boxes and small covers

Sheet-metal panels and small brackets

Old-design or retrofit jobs where slotted head is specified

Simple general-purpose maintenance work

Avoid them when:

You need high torque / production assembly → better with Phillips / Pozi / Torx

Joint is structural or highly loaded → use hex/Allen bolts or coach screws

Installer will mainly use power tools → slotted head cam-out easily

3. Environment & Stainless Grade
a) Choose grade by environment

Normal indoor / mild outdoor / general industrial
→ A2 (SS 304)

Good corrosion resistance

Standard choice for panels, boxes, light sheet-metal work

Coastal / marine / chemical / high-chloride
→ A4 (SS 316)

Better pitting & crevice corrosion resistance

Ideal for marine panels, outdoor boxes, food & pharma, pool plant areas

Dry, non-critical, cost-sensitive indoor use
→ SS 202 (only if acceptable to customer)

Lower corrosion resistance, avoid outdoor / marine / wash-down

b) Match with other hardware

Match screw grade with hinges, latches, clamps, panels where possible, especially if visible or in harsh environments.

4. Head & Drive – Why Pan Slotted?
Pan head

Sits on top of the sheet, no countersink needed

Gives a reasonable bearing area for thin sheet

Good for simple drilled or punched holes

Use pan head when:

Sheet is thin and you don’t want to weaken it with countersinking

A small head projection is acceptable

You want minimal operations (no countersink step)

Slotted drive

Traditional, simple, works with basic flat screwdriver

OK for low torque, hand assembly

Not ideal for power tools or high-torque tightening

Driver slips easily (cam-out)

Head slot can damage quickly

Use slotted when:

Customer or drawing specifically asks for slotted

You want compatibility with older tools / maintenance style

Otherwise, for new designs, Phillips / Pozi / Torx are usually better.

Mechanical Properties (Guide) – SS Pan Slotted Self-Tapping Screws

These screws are usually made from austenitic stainless steel similar in strength to standard A2/A4 fasteners, though self-tappers are often not formally grade-marked like bolts.

A2 (SS 304) Self-Tapping Screws

Material: A2 (≈ SS 304)

Indicative tensile strength: around 700 MPa (similar to A2-70 fastener wire)

Ductility: reasonable – can bend a bit before breaking

Corrosion resistance:

Good in indoor and general outdoor industrial conditions

Suitable for most sheet-metal panels, cabinets, and junction boxes

A4 (SS 316) Self-Tapping Screws

Material: A4 (≈ SS 316)

Indicative tensile strength: similar order to A4-70 (~700 MPa)

Key advantage:

Excellent resistance to chlorides, seawater, and many chemicals

Typical use:

Marine and coastal installations

Outdoor stainless enclosures

Food & pharma equipment, chemical plant panels

SS 202 Self-Tapping Screws (Where Used)

Material: 200-series Cr-Mn stainless

Mechanical strength is generally adequate for light sheet-metal fastening

Corrosion resistance: noticeably lower than 304/316

Should be restricted to dry indoor, low-risk applications.

In real life, for self-tapping screws the limiting factor is usually the sheet material and thread engagement, not the ultimate tensile strength of the stainless screw itself.

10. Quick Selection Cheat Sheet (Floor / Sales Use)

Base Material

Thin sheet metal / plastic with pilot hole → OK for self-tapping

Thick solid metal → consider tapping + machine screw instead

Environment

Standard industrial / indoor / mild outdoor → A2 (304)

Coastal, marine, chemical → A4 (316)

Head & Drive

No flush requirement, simple assembly → Pan slotted self-tapping

Frequent power-tool use / higher torque → prefer pan Phillips/Pozi/Torx

Diameter

Small covers → 3–3.9 mm

General panels → 4.2–4.8 mm

Heavy sheet/brackets → 5.5–6.3 mm

Pilot Hole

Always drill/punch to recommended size

Never “force into solid sheet” without a pilot