oSIST prEN 3381:2026

• Abstract:

  This document specifies the characteristics of screws, 100° countersunk normal head, offset cruciform recess, close tolerance normal shank, short thread, in titanium alloy, anodized, MoS2 lubricated.; Classification: 1 100 MPa1/315 °C.2

• Status: Not Published
• Public Enquiry End Date: 14-Sep-2026
• ICS: 49.025.30 - Titanium
• ICS: 49.030.20 - Bolts, screws, studs
• Technical Committee: I13 - Imaginarni 13
• Current Stage: 4020 - Public enquire (PE) (Adopted Project)
• Start Date: 15-Jul-2026
• Due Date: 02-Dec-2026
• Completion Date: 15-Sep-2026
• Ref Project: prEN 3381 - Aerospace series - Screw, 100° countersunk normal head, offset cruciform recess, close tolerance normal shank, short thread, in titanium alloy, anodized, MoS2 lubricated - Classification: 1 100 MPa (at ambient temperature)/315 °C

• Revises: SIST EN 3381:2026 - Aerospace series - Screws, 100° countersunk normal head, offset cruciform recess, close tolerance normal shank, short thread, in titanium alloy, anodized, MOS2 lubricated - Classification: 1 100 MPa (at ambient temperature) / 315 °C
• Effective Date: 20-Jan-2026

Overview

oSIST prEN 3381:2026 is a draft European standard from the CEN Aerospace series, concentrating on the specification of high-performance aerospace screws. These screws feature a 100° countersunk normal head, an offset cruciform recess, a close tolerance normal shank, and a short thread. Constructed from titanium alloy, they are anodized and lubricated with molybdenum disulphide (MoS₂), and classified for use at a minimum tensile strength of 1 100 MPa at ambient temperature and up to 315 °C.

This standard is crucial for ensuring the quality, safety, consistency, and interoperability of aerospace fasteners, which are fundamental components in demanding aerospace applications. It supersedes EN 3381:2025 and is intended for use by manufacturers, engineers, and procurement professionals within the aerospace sector.

Key Topics

• Scope and Characteristics: Specifies screws with a 100° countersunk head, offset cruciform drive, close tolerance shank, and short thread to support precise assembly in aerospace structures.
• Material Requirements: Mandates the use of titanium alloy (as per TR 3775 and SAE AMS4967) known for its high strength-to-weight ratio and corrosion resistance.
• Surface Treatment: Prescribes anodizing for increased surface durability and MoS₂ lubrication, as per TR 4070 and EN 2491, for reduced friction and wear.
• Dimensional Tolerances: Sets strict requirements for form, position, and mass in accordance with ISO 5856 and ISO 7913 for reliable fit and function.
• Marking and Designation: Details a systematic approach for product identification, ensuring traceability and conformity with EN 2424.
• Quality Management: Requires manufacturing under an approved aerospace quality system, such as EN 9100, and specification of qualification processes such as EN 9133.

Applications

These high-performance titanium screws are tailored for demanding aerospace applications, including:

• Aircraft Structure Assembly: Where secure fastening and minimal weight gain are critical, especially in load-bearing and safety-critical joints.
• Engine and Airframe Components: Withstanding elevated temperatures (up to 315 °C) and high mechanical loads.
• Spacecraft and Satellite Construction: Where corrosion resistance and reliability under variable environmental conditions are essential.
• Repair and Maintenance: For both OEM assembly and aftermarket parts, supporting interoperability and consistent quality.

By adhering to oSIST prEN 3381:2026, aerospace manufacturers and suppliers can ensure:

• Compatibility with international supply chains
• Compliance with stringent safety and quality requirements
• Optimal performance of assembled aerospace components

Related Standards

Professionals implementing oSIST prEN 3381:2026 should consider the following essential and associated standards:

• EN 2424: Marking of aerospace products
• EN 2491: Molybdenum disulphide dry lubricants - Coating methods
• EN 4016: Aerospace series – Oversized bolts
• ISO 5855-2: Aerospace MJ threads - Limit dimensions for bolts and nuts
• ISO 5856: 100° countersunk screws - Dimensions
• ISO 7913: Bolts and screws - Tolerances of form and position
• ISO 9152: Bolts in titanium alloys - Procurement specification
• ISO 14275 / ISO 14276: Internal offset cruciform drives - Metric series
• EN 9100: Quality management systems - Aerospace requirements
• EN 9133: Qualification of standard aerospace products

Adopting oSIST prEN 3381:2026 in conjunction with these aligned standards helps to assure durability, performance, and global compatibility of aerospace fasteners within modern high-stress, temperature-critical applications.

SLOVENSKI STANDARD
01-september-2026
Aeronavtika - Vijaki, 100° ugreznjena glava, križna zareza, polno steblo, ozka
toleranca, kratek navoj, iz titanove zlitine, anodizirane, mazane z MoS2 -
Klasifikacija: 1100 MPa (pri temperaturi okolice)/315 °C
Aerospace series - Screw, 100° countersunk normal head, offset cruciform recess, close
tolerance normal shank, short thread, in titanium alloy, anodized, MoS2 lubricated -
Classification: 1 100 MPa (at ambient temperature)/315 °C
Luft- und Raumfahrt – 100°-Senk-Passschraube mit Flügelkreuzschlitz, kurzes Gewinde,
aus Titanlegierung, anodisiert, MoS2-geschmiert – Klasse: 1100MPa (bei
Raumtemperatur)/315°C
Série aérospatiale - Vis à tête fraisée 100° normale, à empreinte cruciforme déportée,
tige normale à tolérance serrée, filetage court, en alliage de titane, anodisée, lubrifiée au
MoS2 - Classification : 1 100 MPa (à température ambiante)/315 °C
Ta slovenski standard je istoveten z: prEN 3381
ICS:
49.025.30 Titan Titanium
49.030.20 Sorniki, vijaki, stebelni vijaki Bolts, screws, studs
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
July 2026
ICS 49.030.20 Will supersede EN 3381:2025
English Version
Aerospace series - Screw, 100° countersunk normal head,
offset cruciform recess, close tolerance normal shank,
short thread, in titanium alloy, anodized, MoS2 lubricated -
Classification: 1 100 MPa (at ambient temperature)/315
°C
Luft- und Raumfahrt ¿ 100°-Senk-Passschraube mit
Flügelkreuzschlitz, kurzes Gewinde, aus
Titanlegierung, anodisiert, MoS2-geschmiert ¿ Klasse: 1
100 MPa (bei Raumtemperatur)/315 °C
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee ASD-
STAN.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 3381:2026 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Required characteristics . 5
4.1 Configuration – Dimensions – Mass. 5
4.2 Tolerances of form and position . 5
4.3 Materials . 5
4.4 Surface treatment . 5
5 Designation . 8
6 Marking . 8
7 Technical specification . 9
7.1 General. 9
7.2 Quality management system . 9
7.3 Qualification of screws . 9
8 Oversized bolts . 9
Bibliography . 10

European foreword
This document (prEN 3381:2026) has been prepared by ASD-STAN.
After enquiries and votes carried out in accordance with the rules of this Association, this document has
received the approval of the National Associations and the Official Services of the member countries of
ASD-STAN, prior to its presentation to CEN.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 3381:2025.
— normative references updated;
— Figure 1 updated;
— editorially updated.
1 Scope
This document specifies the characteristics of screws, 100° countersunk normal head, offset cruciform
recess, close tolerance normal shank, short thread, in titanium alloy, anodized, MoS lubricated.
1 2
Classification: 1 100 MPa /315 °C.
2 Normative references
The following documents are referred to in the text in such a way that so
...