JIS B1111 Truss Head Phillips Machine Screw – Steel 4.8, Bright Zinc Plated (Cr3)

FULLERKREG supplies JIS B1111 Truss Head Phillips Machine Screws in low carbon steel (Grade 4.8) with a bright zinc plated finish (Zinc Cr3, RoHS-compliant trivalent chromate). The truss head profile features a wide, low-profile dome that distributes clamping load over a larger bearing surface than a standard pan head, making it ideal for thin sheet metal, plastic panels, and general-purpose assemblies where a flush, low-silhouette fastener is required. The bright zinc plating provides reliable corrosion protection for indoor and light outdoor applications while delivering an attractive silver appearance. All screws conform to JIS B1111 dimensional requirements and are available in metric sizes M2 through M6 across a full range of lengths.

Product Specifications

Attribute	Detail
Standard	JIS B1111
Head Type	Truss Head (Wide Low-Profile Dome)
Drive Type	Phillips (Cross Recess)
Material	Low Carbon Steel (A3)
Property Class	4.8
Surface Treatment	Bright Zinc Plated – Trivalent Chromate (Cr3, RoHS Compliant)
Plating Appearance	Bright Silver
Size Range	M2 – M6
Length Range	4 mm – 40 mm
Thread Type	Metric Machine Thread (fully or partially threaded)
Hardness	HV 70–210 (per JIS B1111)
Tensile Strength	≥ 420 N/mm² (Grade 4.8)
Proof Load Stress	310 N/mm² (Grade 4.8)
Brand	FULLERKREG

Dimensional Data (JIS B1111 – Truss Head Phillips Machine Screw)

All dimensions in millimeters (mm). Refer to JIS B1111 for full tolerance specifications.

Nominal Size	Thread Pitch (mm)	Head Diameter D (mm)		Head Height H (mm)		Recess Diameter (mm) Ref	Phillips Driver Size	Unit Weight (g/pc) approx.
		Max	Min	Max	Min
M2	0.4	4.5	4.1	1.3	1.1	2.2	#1	—
M2.5	0.45	5.7	5.3	1.6	1.4	2.5	#1	—
M3	0.5	6.8	6.4	2.05	1.75	2.8	#1	—
M4	0.7	9.4	8.9	2.65	2.35	4.3	#2	—
M5	0.8	11.8	11.2	3.25	2.85	5.0	#2	—
M6	1.0	14.0	13.3	3.9	3.5	6.3	#3	—

* Unit weight column is reserved. Contact FULLERKREG for weight data sheets on specific size/length combinations.

Length Tolerance (JIS B1111)

Nominal Diameter	4 mm or under	Over 4 mm to 10 mm	Over 10 mm to 20 mm	Over 20 mm to 40 mm	Over 40 mm
M2 and M2.5	—	±0.4	±0.6	±0.8	±1.2
M3 and M4	—	±0.4	±0.6	±0.8	±1
M5 and M6	—	±0.8	±1	±1	±1

Zinc Plating – Cr3 (Trivalent Chromate) Overview

Property	Detail
Plating Type	Electrolytic Zinc (Bright)
Chromate Passivation	Trivalent Cr3 (RoHS / ELV compliant – no hexavalent chromium)
Appearance	Bright silver / clear
Typical Plating Thickness	5 – 12 μm
Salt Spray Resistance	≥ 72 hours to white rust (per ISO 9227)
Suitable Environments	Indoor, light outdoor, dry or low-humidity conditions
RoHS Compliance	Yes – Cr3 trivalent chromate, no Cr6+

Selection Guide

Application Scenario	Recommended Size	Notes
Consumer electronics enclosures	M2 – M3	Low-profile truss head suits thin plastic panels; bright finish is aesthetically clean
Sheet metal fabrication	M3 – M5	Wide head prevents pull-through on thin gauge steel or aluminium
Automotive interior trim	M4 – M6	Bright zinc finish meets interior corrosion requirements; RoHS Cr3 compliant
Appliance assembly	M3 – M6	Cost-effective carbon steel with adequate corrosion protection for indoor use
Furniture & fixtures	M4 – M6	Truss head distributes load on wood composites and MDF panels
General MRO / maintenance	M2 – M6	Economical grade 4.8 steel for non-critical structural fastening

Standard Reference

These screws are manufactured and inspected in accordance with JIS B1111 (Japanese Industrial Standard for Cross Recessed Head Machine Screws). The truss head type is defined within JIS B1111 as a wide, low-profile dome head with a flat bearing surface. Base material is low carbon steel (A3) conforming to property class 4.8. Surface finish is electrolytic bright zinc plating with trivalent chromate (Cr3) passivation, compliant with RoHS Directive 2011/65/EU and ELV Directive 2000/53/EC. No hexavalent chromium (Cr6+) is used.

Product Images

Why FULLERKREG

🏭 Direct Manufacturer – Produced in-house with full process control from raw material to finished fastener.
📐 JIS-Compliant Dimensions – Every batch inspected against JIS B1111 tolerances; CMM reports available on request.
⚡ Grade 4.8 Carbon Steel – Material certificates and mechanical test reports provided for traceability.
✨ Bright Zinc Cr3 Plating – RoHS-compliant trivalent chromate; no Cr6+; ≥72 hrs salt spray resistance.
📦 Bulk Wholesale Supply – MOQ-friendly packaging; bulk reels, bags, and boxes available for OEM and MRO customers.
🚢 Global Export Ready – Experienced in international logistics; export documentation and customs support included.
💬 Technical Support – Engineering team available for application consultation, custom length sourcing, and drawing review.