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Hex Phillips SEMS Screw

Pre-Assembled with DIN 125 & DIN 127B Washers  ·  Steel & Stainless Steel 304  ·  M3 to M10

The Hex Phillips SEMS screw is a hex washer head screw, driven with a Phillips screwdriver, pre-assembled at the factory with a DIN 125 plain washer and a DIN 127B spring washer held captive under the head. The washers spin freely but cannot fall off or be left out during assembly — one part to pick and drive instead of three separate components to fit by hand. Excel Trading Corporation stocks in steel with zinc/clear passivate plating and stainless steel 304.

Specifications

Assembly

Hex Phillips Screw + DIN 125 Plain Washer + DIN 127B Spring Washer

Head / Drive

Hex Washer Head  ·  Phillips Cross Recess Drive

Thread Sizes

M3 · M4 · M5 · M6 · M8 · M10

Materials

Steel — Zinc / Clear Passivate  ·  Stainless Steel 304

Washer Fit

Free-spinning & captive — cannot be lost before fitting

Hex Phillips SEMS Screw with DIN 125 Plain Washer and DIN 127B Spring Washer M3 M4 M5 M6 M8 M10 India

Available In

Steel Zinc Plated

Indoor use

Stainless Steel 304

Humid / visible finish

Available Sizes & Washer Dimensions

Stocked lengths vary by diameter — smaller screws are stocked in shorter lengths, larger screws extend further, all within our overall 5mm to 50mm range. Washer outer diameters shown are the maximum tolerance (OD Max) per DIN 125 (plain washer) and DIN 127B (spring washer), pre-fitted under the head.

Thread Pitch (mm) Stocked Lengths (mm) Plain Washer OD Max — DIN 125 (mm) Spring Washer OD Max — DIN 127B (mm)
M3 0.5 5 · 6 · 8 · 10 · 12 · 16 · 20 · 25 7.0 6.2
M4 0.7 6 · 8 · 10 · 12 · 16 · 20 · 25 · 30 9.0 7.6
M5 0.8 8 · 10 · 12 · 16 · 20 · 25 · 30 · 35 10.0 9.2
M6 1.0 10 · 12 · 16 · 20 · 25 · 30 · 35 · 40 12.0 11.8
M8 1.25 12 · 16 · 20 · 25 · 30 · 35 · 40 · 50 16.0 14.8
M10 1.5 16 · 20 · 25 · 30 · 35 · 40 · 50 20.0 18.1

Where Is It Used?

Click your industry to see how Hex Phillips SEMS screws are used.

Material Options

Steel — Zinc / Clear Passivate

Standard stock · Indoor use

Carbon steel with a zinc plated, clear passivate finish. The economical choice for indoor, dry-environment assembly — switchboards, appliance interiors, general sheet metal work. Adequate corrosion protection for sheltered conditions; not intended for prolonged outdoor or washdown exposure.

Switchboards · Appliance interiors · General fabrication · Indoor panels

Stainless Steel 304

Corrosion resistant · Visible finish

304-grade austenitic stainless steel, screw and both washers. Fully corrosion resistant with a clean, bright finish — the right choice wherever the fastener is visible on a finished product, exposed to humidity or washdown, or used in food-adjacent or hygienic equipment where rust staining is unacceptable.

Visible enclosures · Humid environments · Washdown areas · Hygienic equipment

Quick Specifications

M3–M10

Thread Range

5–50mm

Length Range

2 Washers

DIN 125 + DIN 127B

Phillips

Drive Type

Installation Notes

  • ▸ The spring washer must be fully compressed flat for its anti-loosening effect to work — stop driving once it sits flush, not before.
  • ▸ Do not overtighten on thin sheet metal — the plain washer spreads load well, but excessive torque can still dish or crack a thin panel around the hole.
  • ▸ The washers spin freely on the shank — this is normal and does not indicate a fault. They are captive (cannot slide off), not fixed rigid.
  • ▸ Use a correctly sized Phillips bit in good condition — a worn bit on a hex-headed screw can cam out before the joint is properly seated, since there is no hex drive surface to fall back on.

Frequently Asked Questions

What is a SEMS screw?

SEMS stands for "Sems" (originally a trademark, now used generically) — a screw pre-assembled at the factory with one or more washers held captive under the head. Instead of picking a screw and washer separately and fitting them by hand on the assembly line, the washer is already in place and free-spinning on the shank, so it can never be forgotten, dropped or fitted the wrong way round.

Why does this screw come with two different washers — a plain washer and a spring washer?

The two washers do different jobs. The DIN 125 plain washer sits against the work surface and spreads the clamping load over a wider area, protecting soft or painted surfaces from the screw head. The DIN 127B spring washer sits between the plain washer and the screw head — as the screw is tightened, it compresses flat and its spring tension resists the screw backing off under vibration.

Can the washers be removed, or are they permanently fixed?

The washers are captive, not permanently fixed. A small crimp or rolled step on the screw shank, below the washer stack, stops them sliding off the end — but they still spin freely on the shank and can be slid off over the threads if genuinely needed. "Captive" means they cannot be lost or fall off during handling and installation, not that they are welded or glued in place.

Should I choose steel zinc plated or stainless steel 304?

Steel with zinc/clear passivate plating is the economical choice for indoor, dry environments — the majority of switchboard, appliance and general fabrication assembly. Stainless steel 304 is worth the extra cost wherever the fastener is visible on a finished product, exposed to humidity, washdown or mild outdoor conditions, or used in food-adjacent or hygienic equipment where corrosion or rust staining is unacceptable.

What's the advantage over fitting a separate screw and washer by hand?

Functionally the clamped joint is similar, but a SEMS screw is a single part to pick, store and drive — no separate washer to keep in stock, no risk of an operator skipping the washer under time pressure, and no washer that can be fitted upside down or left out entirely. On a production line this measurably speeds up assembly and removes a common source of missed-part defects.

Where can I buy Hex Phillips SEMS screws in Bangalore?

Excel Trading Corporation stocks Hex Phillips SEMS screws with DIN 125 plain washer and DIN 127B spring washer, in steel zinc plated and stainless steel 304, M3 to M10, at our Kumbarpet store in Bengaluru. We supply switchboard manufacturers, appliance assemblers, automotive fabricators and general industry across Karnataka and India-wide. Call +91-9448239476 or email info@exceltrading.in for pricing and bulk availability.