Phillips Sems Screws Double Washer Flat And Spring Metric M3 M4 M5 M6
Sems screw vs. regular screw – what’s the difference?
| Feature | Regular screw + loose washer | Sems screw (pre‑assembled) |
|---|---|---|
| Handling | Two separate parts | One piece, ready to use |
| Assembly time | Slower – pick up washer, then screw | Faster – grab and drive |
| Washer loss during maintenance | High risk – washer falls off | Zero – washer stays captive |
| Inventory | Two SKUs (screw + washer) | One SKU |
| Consistency | Varies – washer type may mismatch | Same washer type every time |
Which washer do you need? – A quick guide
| Your application | Recommended washer | Why |
|---|---|---|
| Motors, fans, vibrating machinery | Spring washer | Prevents loosening from vibration |
| Soft materials (plastic, aluminum, thin sheet metal) | Flat washer | Spreads clamping force, prevents surface damage |
| Heavy vibration, outdoor equipment, pumps | External tooth lock washer | Teeth dig into surface, maximum anti‑rotation |
| Electronics, clean appearance, no snagging | Internal tooth lock washer | Teeth grip screw head, smooth outside |
| Demanding industrial applications | Double washer (spring+flat) | Anti‑vibration + pressure distribution |
Head style options
- Phillips pan head – The standard choice. Works with any Phillips screwdriver. Flat underside presses evenly.
- Hex head – Requires a wrench or socket. Higher torque capability. Good for tight spaces where a screwdriver won’t fit.
Material selection
| Material | Best for |
|---|---|
| 304 stainless steel | Outdoor, wet, mildly corrosive environments |
| 316 stainless steel | Marine, saltwater, chemical exposure |
| Zinc plated carbon steel | Indoor, light outdoor, cost‑sensitive projects |
Sizes & strength
- Metric M3, M4, M5, M6. Standard lengths 6–30 mm. Custom lengths on request.
- Strength grades: 8.8 (general industrial), 10.9 (higher load), 12.9 (maximum strength).
Typical applications
Electronics assembly, PCB mounting, control panels, industrial machinery, automotive components, marine enclosures, HVAC units, furniture manufacturing, and general factory assembly.
Quality assurance
ISO 9001 and ISO 10012 certified. Every batch undergoes thread gauging, dimensional inspection, and hardness testing. Washer retention tested to ensure no detachment.
Custom manufacturing
Need a non‑standard size, special head marking, or unusual washer combination? Send us your drawing or sample. We produce exactly what you require. OEM orders welcome.
Company profile
YH Fastener – founded in 1998. Specialized in sems screws, self tapping screws, machine screws, shoulder screws, Machine screw,and custom fasteners. Factory direct pricing. Shipping to over 60 countries.
- Screw + washer pre‑assembled – one part instead of two
- No more lost washers during maintenance
- Choose from 5 washer types: spring, flat, external tooth, internal tooth, double
- 304 stainless, 316 stainless, or zinc plated carbon steel
- Metric M3 to M6, Class 8.8, 10.9, 12.9
- Ideal for electronics, industrial equipment, PCB mounting, marine, HVAC