Premium A2 (304) and A4 (316) stainless steel pan slotted machine screw. Available in metric coarse threads and select UNC/BSW on request. Mill Test Certificates (MTC), strict dimensional tolerances, and fast dispatch from ready stock.
DIN 85
Stainless Steel Pan Slotted Machine Screw
TRSUTED SS pan slotted machine screw FOR DEMANDING APPLICATION
Key Specifications
Standards
-
Grades (Material)
A2 (304), A4 (316)
Strength Classes
-
Threads
Metric coarse (default). Fine/UNC/BSW available on request
Sizes
M1.6 to M 70, 3/16" to 2.1/2" (others on request)
Lengths
-
Head
-
Marking
Grade/class & manufacturer ID as applicable
Certificates
MTC 3.1 / chemical composition & mechanicals available
Compliance
RoHS/REACH; generally non-magnetic in solution-annealed state (slight magnetism possible after cold-work)
Choosing the Right Stainless Steel Pan Slotted Machine Screw
Choosing the Right SS Pan Slotted Machine Screw (Guide)
for stainless steel pan head, slotted, machine screws
1. What is an SS Pan Slotted Machine Screw?
An SS pan slotted machine screw is:
A fully threaded, straight shank screw
With a pan head (low, rounded top and flat bearing face)
With a single straight slot in the head (for flat screwdriver)
Designed to be used with a nut or in a tapped (threaded) hole, mainly in metal or rigid plastic
It is not self-tapping – threads already exist (nut/tapped hole).
Typical uses:
Electrical / electronic enclosures
Instrument panels and control boxes
Light machinery, brackets, terminal strips
Mounting covers, lids, plates, small hardware
2. Application & When to Use Pan Slotted Machine Screws
Choose SS pan slotted machine screws when:
You are bolting metal to metal or plastic to metal with a nut or tapped hole
Loads are light to medium
A low but visible head is acceptable (no need for flush finish)
Assembly/maintenance is done with simple hand tools (flat screwdriver)
Avoid them when:
The joint is highly loaded or safety-critical → consider hex head or socket head (Allen) screws
You need a flush surface → use CSK (countersunk) machine screws
Assembly is mainly done by power tools / high speed → slotted heads slip easily; Phillips/Pozi/Torx are better.
3. Environment & Stainless Grade Selection
a) By environment
Indoor / mild outdoor / general industrial
→ A2 (SS 304)
Standard choice
Good corrosion resistance for most electrical & mechanical applications
Coastal / marine / high-chloride / chemical
→ A4 (SS 316)
Better resistance to chlorides, salt spray, many chemicals
Recommended for marine enclosures, food & pharma, chemical plant equipment
Budget, dry indoor, non-critical
→ SS 202 (only if customer accepts)
Lower corrosion resistance
Avoid for long-term outdoor or moist environments
b) Match surrounding materials
Match screw grade with other visible hardware (hinges, brackets, trims).
In very aggressive environments, keep all exposed hardware A4 to avoid mixed corrosion performance.
Mechanical Properties (Guide)
Mechanical Properties (Guide) – SS Pan Slotted Machine Screws
Most SS machine screws follow strength classes similar to stainless bolts.
A2-70 (SS 304) – Most Common
Material: A2 (approx. SS 304)
Strength class: 70
Minimum tensile strength: ~700 MPa
Proof (yield) strength: ~450 MPa
Use:
General purpose machine assemblies
Electrical enclosures, light machinery, brackets, covers
Indoor & outdoor environments without extreme chlorides
A4-70 / A4-80 (SS 316) – Higher Corrosion Resistance
Material: A4 (approx. SS 316)
Strength class:
A4-70 → tensile ~700 MPa
A4-80 → tensile ~800 MPa (higher strength variants)
Use:
Marine/coastal applications
Food & beverage, pharma, and chemical plant equipment
A4-80 where both high strength + high corrosion resistance are needed
SS 202 Machine Screws (Where Used)
Material: Cr-Mn stainless (202 type)
Strength: generally adequate for many light machine applications
Corrosion: lower than 304/316 – limit to dry indoor or non-critical environments.
In most small machine-screw applications, female thread strength (nut or tapped hole) and joint design (washer, bearing area) determine performance as much as screw tensile strength.
10. Quick Selection Cheat Sheet (For Sales / Shop Floor)
Environment
Normal indoor/outdoor → A2-70 (SS 304)
Coastal/marine/chemical → A4-70 / A4-80 (SS 316)
Only dry indoor & very cost-sensitive → SS 202 (if accepted)
Head & Drive
Visible, low head, easy to assemble with hand tools → pan slotted
Need flush surface → CSK machine screw
Need higher torque / frequent tool use → consider hex/socket/PH/PZ/Torx instead of slotted.
Size
Electronics / small parts → M2–M3
General panels & brackets → M3–M6
Heavier duty → M8+ (and often hex/socket head)
Length
Nut joint → plates + washers + nut + 1–3 threads out
Tapped hole → 1–1.5 × diameter thread engagement in steel.
Assembly
Correct screwdriver size, steady pressure
Use washers where needed
Consider anti-seize for SS–SS threads and don’t over-torque.
6000+ Products
Trusted by 2000+ Clients
40+ Years of Experience
Exporting to 12+ Countries
What We Do
From a vast manufacturing facility situated in GIDC Wadhwan, Gujarat to strategic
sales offices in Mumbai and Chennai, we design, produce, and deliver a wide array of stainless steel
fasteners, hex bolts, machine screws, socket screws, washers, nuts, self‑tapping screws, threaded rods,
anchor fasteners, and specialty material products, engineered for demanding sectors like petrochemicals,
pharmaceuticals, automotive, and construction.
Our Legacy & Mission
Founded on a vision of precision and service, we have consistently expanded our
capabilities to meet evolving industrial needs. Our commitment to "We Deliver Quality" reflects in the
long-term relationships we build with clients across India and abroad.
Frequently Asked Questions
What is an SS pan slotted machine screw?
It’s a fully threaded stainless steel screw with a pan (rounded) head and a straight slot, designed to be used with a nut or in a tapped (threaded) hole in metal or rigid plastic. It does not tap its own thread.
Where are SS pan slotted machine screws commonly used?
They’re widely used in:
Electrical and electronic enclosures & control panels
Instrument panels and terminal strips
Light machinery and brackets
Mounting covers, lids, and small hardware assemblies
Anywhere you’re bolting parts together with a nut or tapped hole, and a neat but visible head is acceptable.
What’s the difference between a machine screw and a self-tapping screw?
Machine screw:
Straight shank, uniform machine thread
Needs a nut or a tapped hole
Does not cut its own mating thread
Self-tapping screw:
Usually tapered with special thread
Forms its own thread in sheet metal/plastics
Often used without a nut
SS pan slotted machine screws are machine screws, not self-tapping.
Why choose a pan head instead of a countersunk (CSK) head?
Choose pan head when:
You don’t need a flush surface
The material is thin and you want to avoid countersinking
A small, rounded, visible head is acceptable on the surface
Choose CSK head when:
You want the head to be flush with the surface
Aesthetics or function require a flat finish (no projection).
Which stainless grade should I choose – 304 (A2) or 316 (A4)?
A2 / SS 304:
Standard choice for indoor and general outdoor industrial use
Good corrosion resistance for most enclosures and machines
A4 / SS 316:
Better for coastal, marine, poolside, and chemical environments
Higher resistance to chlorides and harsh atmospheres
For harsh environments or hygiene-critical sectors (food, pharma), A4 is preferred.
