SEMS Screw: Internal Tooth, #4-40 Thread Size, 1/2 in Lg, Steel, Zinc-Plated
The SEMS Screw: Internal Tooth is a #4-40 thread size, 1/2-inch-long machine screw with an internal tooth lock washer, made of steel with a zinc-plated finish, pan head, and Phillips drive (size #1), supplied in a…
SKU 3G-OTH-532108
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Product Description
The SEMS Screw: Internal Tooth is a #4-40 thread size, 1/2-inch-long machine screw with an internal tooth lock washer, made of steel with a zinc-plated finish, pan head, and Phillips drive (size #1), supplied in a 100-piece pack (MPN MPPII0-400500-100P).
Frequently Asked Questions
What is a SEMS screw with internal tooth lock washer used for?
A SEMS screw with an internal tooth lock washer is used to fasten components while resisting loosening from vibration. The pre-assembled washer bites into the mating surface, making it ideal for electrical panels, machinery, and automotive assemblies where a secure, permanent hold is required.
What are the specifications of the SEMS screw #4-40 x 1/2 in?
This SEMS screw has a #4-40 thread size, 1/2 in length, steel construction with zinc-plated finish, pan head, and Phillips drive size #1. It includes an internal tooth lock washer and comes in a 100-piece pack (MPN MPPII0-400500-100P).
Where to buy SEMS screws #4-40 worldwide?
3G Electric supplies SEMS screws #4-40 x 1/2 in with internal tooth lock washers worldwide. As a global industrial solutions provider, we handle full logistics and customs clearance to deliver genuine SEMS fasteners to your facility, regardless of location.
How to install a SEMS screw with internal tooth lock washer?
Install a SEMS screw by driving it with a #1 Phillips bit into a pre-tapped or threaded hole. The internal tooth washer is pre-assembled, so no separate washer is needed. Tighten to the recommended torque for #4-40 steel fasteners; the washer's teeth embed into the surface to prevent loosening.
SEMS Products
3G Electric supplies SEMS machine screws with internal tooth lock washers. We supply genuine products with in-stock availability on common SKUs, technical documentation, commissioning support, and warranty service — worldwide.









