FprEN 3293

• Abstract:

  This document specifies the dimensions of uncoated T-head bolts, close tolerance, with MJ-thread, medium thread length, in heat-resisting nickel base alloy NI-P100HT for aerospace applications.; Maximum test temperature of the parts is 650 °C.; These bolts are used in aerospace fastening systems mainly stressed in shearing force.

• Status: Not Published
• Publication Date: 29-Nov-2026
• ICS: 49.030.20 - Bolts, screws, studs
• Technical Committee: ASD-STAN - Aerospace
• Drafting Committee: ASD-STAN/D 3/S 2 - Fasteners
• Current Stage: 6055 - CEN Ratification completed (DOR) - Publishing
• Start Date: 28-Sep-2026
• Completion Date: 28-Sep-2026
• Ref Project: kSIST FprEN 3293:2026 - Aerospace series - Bolts, T-head, close tolerance, medium thread length, in heat resisting nickel base alloy NI-P100HT (Inconel 718), uncoated - Classification: 1 275 MPa/650 °C

• Revises: EN 3293:2008 - Aerospace series - Bolts, T-head, close tolerance, medium thread length, in heat resisting nickel base alloy NI-P100HT (Inconel 718), uncoated - Classification: 1 275 MPa/650 °C
• Effective Date: 12-Feb-2025

FprEN 3293 is a CEN draft European Standard for uncoated, close-tolerance T-head bolts for aerospace use. It specifies the dimensions, designation, marking, material reference and technical specification for MJ-thread bolts made from heat-resisting nickel base alloy NI-P100HT (Inconel 718), classified as 1 275 MPa/650 °C. The bolts are intended mainly for aerospace fastening systems that are stressed in shear.

What does FprEN 3293 specify?

FprEN 3293 specifies the dimensions of uncoated T-head bolts with close tolerance, MJ-thread and medium thread length for aerospace applications. It also sets the associated designation, marking and technical specification, so users can identify the correct bolt and check that it matches the intended aerospace fastener definition.

The document is organized into these clauses:

• Scope
• Normative references
• Terms and definitions
• Required characteristics
• Designation
• Marking
• Technical specification

For practical use, that means the standard is not just a drawing standard. It combines the bolt geometry with the material basis and the identification rules needed for ordering, inspection and product marking.

What are the key requirements of FprEN 3293?

FprEN 3293 focuses on a defined bolt family rather than a general fastener range. The main requirement is that the bolt form, size limits and material basis stay within the document so the parts fit aerospace joints reliably.

Geometry, dimensions and tolerances

Clause 4.1 ties the bolt configuration to Figure 1 and the dimensions, tolerances and masses to Tables 1 and 2. The document also states that unspecified details of form are left to the manufacturer's option. In practice, this means the buyer or inspector checks the stated dimensions and does not assume extra shape features beyond what is shown.

The figure and tables cover the nominal diameter codes and lengths used for this bolt family. The notes in Figure 1 also control thread runout, lead thread and the way certain measurements are taken when the shank is shorter than the nominal shank diameter. That matters because close-tolerance bolts are sensitive to fit, alignment and how dimensional checks are made.

Edge condition and thread form

Clause 4.1 requires sharp edges to be broken within a small radius range, and it links thread runout and lead thread to ISO 3353-1. It also states that the thread major diameter tolerance is modified according to Figure 1. In practice, this gives the manufacturer and inspector a clear rule for the thread area, which is critical for assembly and load transfer.

Material and surface condition

Clause 4.2 requires the nickel alloy to comply with TR 3775, for example SAE AMS5662. Clause 4.3 states that the surface treatment is none. That means the bolt is supplied uncoated, so users should not plan on a protective coating or plating unless a separate specification says otherwise.

Identification and marking

Clause 5 gives the designation structure: the document number, then the nominal diameter code, then the length code. Clause 6 requires marking in accordance with EN 2424, Style A. This is important for procurement and traceability because the bolt can be identified without measuring it again.

Technical specification

Clause 7 requires compliance with EN 2583. In practice, FprEN 3293 gives the dimensional definition, while EN 2583 supplies the technical requirements that the bolt also has to meet.

What terms does FprEN 3293 define?

FprEN 3293 does not provide a separate list of formal definitions, but it uses these key terms consistently:

• T-head bolt - A bolt with a T-shaped head, used where the head profile must suit a matching slot or joint detail.
• Close tolerance - A tighter dimensional control class that helps the bolt fit and locate accurately in aerospace assemblies.
• MJ-thread - The aerospace metric thread form used for these bolts and governed here by ISO 5855-1 and ISO 5855-2.
• Medium thread length - A thread length category used to define the usable threaded portion of the bolt.
• NI-P100HT - The heat-resisting nickel base alloy named in the title and scope for these bolts.
• Inconel 718 - The common alloy name given alongside NI-P100HT.
• EN 2424 - The marking standard used for identifying the finished aerospace product.
• TR 3775 - The material reference used to identify the nickel alloy basis for the bolt.

Who uses FprEN 3293?

FprEN 3293 is used by aerospace designers, fastener manufacturers, quality managers, inspectors and procurement teams. Designers use it to select a bolt with the right head form, thread and length for a shear-loaded joint. Manufacturers use it to make the bolt to the correct dimensions and material condition. Quality and receiving teams use it to verify marking, size codes and conformance to the listed technical specification.

What changed in FprEN 3293 from the previous edition?

FprEN 3293 supersedes EN 3293:2008. The foreword states two significant technical changes:

• SAE AMS5662 was added as a material standard.
• Clause 3.4, “Thread surface”, was removed.

Which standards are used with FprEN 3293?

• EN 2424 - gives the marking style for aerospace products.
• EN 2583 - provides the technical specification that these bolts have to meet.
• ISO 3353-1 - covers lead and runout threads for rolled external threads.
• ISO 5855-1 - gives the general requirements for MJ threads.
• ISO 5855-2 - gives the limit dimensions for MJ bolts and nuts.
• TR 3775 - provides material guidance for bolts and pins.
• SAE AMS5662 - is named as an example material standard for the nickel alloy.

What does the FprEN 3293 document contain?

FprEN 3293 contains a figure showing the bolt configuration and two main tables for the dimensional system. Table 1 gives the coded diameter sizes and their limits, while Table 2 gives the matching length and mass data. The document also includes the designation format, the marking rule and the clause that links the bolt to EN 2583. For users, that means it supports design selection, production control, inspection and identification of a specific aerospace bolt type.

SLOVENSKI STANDARD
oSIST prEN 3293:2025
01-september-2025
Aeronavtika - Sorniki, glava T, ozka toleranca, srednja navojna dolžina, iz
toplotnoodporne zlitine na nikljevi osnovi NI-P100HT (Inconel 718), brez prevleke -
Klasifikacija: 1 275 MPa/650 °C
Aerospace series - Bolts, T-head, close tolerance, medium thread length, in heat
resisting nickel base alloy NI-P100HT (Inconel 718), uncoated - Classification: 1 275
MPa/650 °C
Luft- und Raumfahrt - T-Kopf-Passschrauben, mittlere Gewindelänge, aus
hochwarmfester Nickelbasislegierung NI-P100HT (Inconel 718), blank - Klasse: 1 275
MPa/650 °C
Série aérospatiale - Vis de précision à tête bihexagonale, à filetage moyen, en alliage
résistant à chaud à base de nickel NI-P100HT (Inconel 718), non revêtu - Classification :
1 275 MPa/650 °C
Ta slovenski standard je istoveten z: prEN 3293
ICS:
49.030.20 Sorniki, vijaki, stebelni vijaki Bolts, screws, studs
oSIST prEN 3293:2025 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

oSIST prEN 3293:2025
oSIST prEN 3293:2025
DRAFT
EUROPEAN STANDARD
prEN 3293
NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2025
ICS 49.030.20 Will supersede EN 3293:2008
English Version
Aerospace series - Bolts, T-head, close tolerance, medium
thread length, in heat resisting nickel base alloy NI-
P100HT (Inconel 718), uncoated - Classification: 1 275
MPa/650 °C
Série aérospatiale - Vis de précision à tête Luft- und Raumfahrt - T-Kopf-Passschrauben, mittlere
bihexagonale, à filetage moyen, en alliage résistant à Gewindelänge, aus hochwarmfester
chaud à base de nickel NI-P100HT (Inconel 718), non Nickelbasislegierung NI-P100HT (Inconel 718), blank -
revêtu - Classification : 1 275 MPa/650 °C Klasse: 1 275 MPa/650 °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
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 3293:2025 E
worldwide for CEN national Members.

oSIST prEN 3293:2025
prEN 3293:2025 (E)
Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Required characteristics . 4
4.1 Configuration, dimensions, tolerances, masses . 4
4.2 Material . 8
4.3 Surface treatment . 8
5 Designation . 8
6 Marking . 8
7 Technical specification . 8

oSIST prEN 3293:2025
prEN 3293:2025 (E)
European foreword
This document (prEN 3293:2025) 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 3293:2008.
prEN 3293:2025 includes the following significant technical changes with respect to EN 3293:2008:
— material standard SAE AMS5662 added;
— 3.4 “Thread surface” removed.
oSIST prEN 3293:2025
prEN 3293:2025 (E)
1 Scope
This document specifies the dimensions of uncoated T-head bolts, close tolerance, with MJ-thread,
medium thread length, in heat-resisting nickel base alloy NI-P100HT for aerospace applications.
Maximum test temperature of the parts is 650 °C.
These bolts are used in aerospace fastening systems mainly stressed in shearing force.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
EN 2424, Aerospace series — Marking of aerospace products
EN 2583, Aerospace series — Bolts, MJ threads, in heat resisting nickel base alloy NI-PH2601
(Inconel 718) — Classification: 1 275 MPa (at ambient temperature)/650°C — Technical specification
ISO 3353-1, Aerospace — Lead and runout threads — Part 1: Rolled external threads
ISO 5855-1, Aerospace — MJ threads — Part 1: General requirements
ISO 5855-2, Aeros
...