ScrewSourceCarbon Steel
Screw & Washer Assemblies
Screw and washer assemblies (often called combo screws or SEMS screws) come with a plain and/or spring washer pre-fitted on the screw. One part instead of two means faster assembly lines and no loose washers at the workstation. We supply 304 stainless hex socket and hex head assemblies as part of the current catalog.
Pan Head Self-Tapping Screw & Washer Assemblies (PWA Series) — Black Oxide
Pan head self-tapping screw-and-washer assemblies — one-step tapping assembly with captive washers.
Pan Head Self-Tapping Screw & Washer Assemblies (PWA Series) — Nickel Plated
Pan head self-tapping screw-and-washer assemblies — one-step tapping assembly with captive washers.
Pan Head Machine Screw & Washer Assemblies (PWB Series) — Black Oxide
Pan head machine screw-and-washer assemblies — pre-fitted washers over tapped joints.
Pan Head Machine Screw & Washer Assemblies (PWB Series) — Nickel Plated
Pan head machine screw-and-washer assemblies — pre-fitted washers over tapped joints.
Pan Head Machine Screw & Washer Assemblies (PWM Series) — Black Oxide
Pan head machine screw-and-washer assemblies — pre-fitted washers over tapped joints.
Pan Head Machine Screw & Washer Assemblies (PWM Series) — Nickel Plated
Pan head machine screw-and-washer assemblies — pre-fitted washers over tapped joints.
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About this category
The captive washer spins freely but cannot fall off. The plain washer distributes the clamping load; the spring washer adds tension that resists loosening under vibration. Pre-assembly removes a picking and alignment step from the line, which matters most in high-volume electronics and appliance production.
Assemblies are specified the same way as the base screw — head style, drive, material, finish, diameter and length — with the washer combination noted. If you need a specific washer arrangement, describe it in the RFQ and we will match the sourcing option.
Typical applications
- High-volume electronics and appliance assembly lines
- Sheet metal housings where a loose washer is impractical
- Service and repair kits that must stay complete
- Any workstation where reducing parts handling pays off
Materials & finishes
Carbon steel screws supplied in two surface finishes: bright nickel plating for a clean decorative look, and black oxide for a low-glare, economical technical finish. The base steel is the same in both lines — the finish changes appearance and mild-corrosion behaviour, so stainless steel stays the choice for damp and outdoor use. Current lines cover self-tapping, machine, hex socket and screw-and-washer assemblies. Any specific size or grade depends on the item and is confirmed with your quotation.
304 stainless — sourcing and supply experience; availability depends on specification.
Screw & Washer Assemblies — common questions
Which washer combinations are available?
Our current catalog covers common plain + spring combinations in 304 stainless. Other arrangements depend on specification — send the requirement with your RFQ and we will confirm availability with a quotation.
Why choose an assembly instead of a screw plus separate washers?
Fewer parts to order, stock and handle; no washer dropped on the line; consistent fit every time. The unit price is higher than a bare screw, but total assembly cost is usually lower — quotation based on quantity will show the difference for your volume.
Can't find the exact spec? We source it.
Send your sizes and requirements — quotation based on quantity and specification, with this category's context attached.
