Material
Stainless Steel
Type
Pan head Phillips, captive spring + flat washer
Size Range
M3–M8
Surface Finish
Plain / Passivated
Grade
A2-70 / A4-80
Standard
SEMS · DIN 7985 base
Packaging
Carton / Pallet
MOQ
1 piece (sample)
Precision Manufacturing, Batch After Batch
From cold-heading raw steel wire to heat-treated finished bolts, every step runs under strict in-house process control — ensuring the dimensional accuracy and strength grade printed on every head marking.
Product Overview
Application Scenarios
Combination screws — also called SEMS screws — are a pan head cross-recess machine screw with a spring washer and flat washer permanently held captive under the head, pre-assembled at the factory. Because the washers cannot be lost or forgotten on the assembly line, they speed up assembly and guarantee that every joint gets its washer. The spring washer resists loosening under vibration while the flat washer spreads the load and protects the surface. They are widely used in electrical panels and switchgear, appliances, electronics, motors and general equipment assembly.
Installation Notes
Drive into a tapped hole, nut or captive thread with the correctly sized Phillips bit (PH1 for M3, PH2 for M4–M5, PH3 for M6, PH4 for M8). The captive washers work automatically — there is no need to add a separate washer. Tighten to compress the spring washer flat against the surface, but do not over-torque: these are grade 4.8 / 8.8 machine screws, not high-strength fasteners. Because the washers are retained by the rolled thread, they stay on the screw throughout handling and assembly.
Material & Certification
Manufactured from austenitic stainless steel — A2 (AISI 304) or A4 (AISI 316) — to ISO 3506-1, with stainless spring and flat washers assembled captive before thread rolling; every batch is traceable to raw material certificates. Each production run passes 100% dimensional, cross-recess and washer-retention inspection before packaging; EN 10204 3.1 material certificates are available on request.
Combination Screw (with Washer)
Stainless Combination Screw · A2-70 / A4-80 · 304 / 316 · Pan Head + Washer
Dimensional Specifications
Pan Head (DIN 7985) Reference Dimensions — click a size to locate it below
| Thread Size | Head Dia dk (mm) | Head Height k (mm) | Cross Recess (No.) |
|---|---|---|---|
| M3 | 6.0 | 2.4 | PH1 |
| M4 | 8.0 | 3.1 | PH2 |
| M5 | 10.0 | 3.8 | PH2 |
| M6 | 12.0 | 4.6 | PH3 |
| M8 | 16.0 | 6.0 | PH4 |
Head dimensions per DIN 7985 pan head; captive spring + flat washer added as an assembly. Washer size and type can be specified — contact us for custom specification sheets.
Applications
Construction
Steel structures, bridges, buildings, concrete anchors
Machinery
Heavy equipment, industrial machines, manufacturing
Infrastructure
Railways, towers, pipelines, power transmission
Automotive
Vehicle assembly, chassis, engine components
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Factory-direct combination screws exported to construction, machinery and infrastructure buyers across Europe, Africa, Asia and the Americas.