304 Stainless Steel Sems Screws Pan Head Phillips Spring Washer Pre Assembled Metric M3 M4 M5 For Electronics Box
A sems screw is a regular screw with a washer already stuck under the head. You do not have to pick up a washer and slide it on. It comes as one piece. This might not sound like a big deal but on a busy assembly line it saves seconds on every screw. Those seconds add up.
You grab one part instead of two.
When you take the screw out later for maintenance the washer stays on the screw. It does not fall into your machine or onto the floor.
Spring washer: Looks like a split ring. When you tighten the screw it pushes back. This keeps the screw from vibrating loose. Good for motors, fans, anything that shakes.
Flat washer: Just a flat ring. It spreads the clamping force over a bigger area. Good for plastic or thin metal where you do not want to dent the surface.
External tooth lock washer: Has sharp teeth that point outward. The teeth dig into the work surface. This gives you a mechanical lock against rotation.
Internal tooth lock washer: Teeth point inward toward the screw head. Looks cleaner on the outside. Nothing sticks out to snag on wires or cables.
Double washer: Spring plus flat together. You get anti vibration and pressure distribution in one screw. Popular for demanding jobs.
Phillips pan head: The flat underside presses evenly.
Hex head: Needs a wrench or socket. You can get more torque than a screwdriver. Good for tight spaces where you need a strong clamp.
304 stainless steel. Does not rust. Good for outdoor or wet places.
316 stainless steel. Extra rust protection. Use it near salt water.
Carbon steel with zinc plating. Strong and budget friendly. The zinc coating stops basic rust.
Metric M3, M4, M5, M6. Lengths from 6mm up to 30mm. Need a different size? We can make it.
Grade 8.8 for most jobs. Grade 10.9 for heavier loads. Grade 12.9 for the toughest applications.
Anywhere you want to move fast and not think about loose washers.
We measure every batch. We test the threads. We check hardness. ISO 9001 and ISO 10012 certified. You get the same thing every time you order.
YH Fastener started in 1998. We make sems screws, machine screws, self tapping screws, and custom fasteners. ISO 9001 and ISO 10012 certified. We check every batch. Factory direct. Ship to 60+ countries.
