FprEN 6122

Aerospace series - Blind bolt, 130° flush head, high strength

This document specifies the configuration, dimensions, tolerances and mass of a stainless steel and titanium blind bolt with 130° flush head for aerospace application.

Luft- und Raumfahrt - Blindbolzen, 130° Senkkopf, hochfest

Série aérospatiale - Boulon aveugle, Tête fraisée 130°, haute résistance

Le présent document spécifie la configuration, les dimensions, les tolérances et la masse d’un boulon aveugle en acier inoxydable et titane, à tête fraisée 130°, pour les applications aérospatiales.

Aeronavtika - Slepa kovica, 130° ugrezna glava, visoka trdnost

General Information

• Status: Not Published
• Publication Date: 03-Jan-2027
• ICS: 49.030.20 - Bolts, screws, studs
• Technical Committee: ASD-STAN - Aerospace
• Drafting Committee: ASD-STAN/D 3/S 2 - Fasteners
• Current Stage: 4599 - Dispatch of FV draft to CMC - Finalization for Vote
• Start Date: 29-May-2026
• Completion Date: 29-May-2026
• Ref Project: oSIST prEN 6122:2024 - Aerospace series - Blind bolt, 130° flush head, high strength

Overview

FprEN 6122 is a draft European Standard developed by CEN for the aerospace industry, specifying the requirements for high-strength blind bolts with a 130° flush head. These fasteners are available in stainless steel (CRES) and titanium, designed for use where access is only possible from one side of the structure-making them especially valuable in aerospace manufacturing and maintenance. The standard establishes configuration, dimensions, tolerances, materials, finishes, and mass characteristics, ensuring reliability and compatibility across aerospace applications.

Key Topics

• Configuration & Dimensions
  • Specification of the geometry, including the flush head angle of 130°, diameter codes, grip lengths, and associated tolerances.
  • Options for both standard and first oversize ("X") bolts, enhancing adaptability in repair scenarios.
• Materials & Finishes
  • Details on available materials: stainless steel (A-286 CRES, 316 CRES) and commercially pure titanium.
  • Guidance on finishes and passivation requirements per industry standards such as SAE AMS2700 and ISO 8080.
• Strength & Performance
  • Minimum requirements for static strength, tensile preload, and spindle retention, addressing both CRES and titanium variants.
• Marking & Identification
  • Requirements for product marking to EN 2424:2008, including designation of oversize bolts.
• Compatibility
  • Alignment with other technical specifications, notably NASM 8975 for installation and performance requirements.

Applications

FprEN 6122 blind bolts are engineered to meet the demanding requirements of modern aerospace assemblies. Key application areas include:

• Aircraft Structures
  • Joining panels, spars, ribs, and skins where rear access is not possible or practical.
  • Fastening components requiring a flush surface for aerodynamic performance.
• Maintenance & Repair
  • Use of first oversize (“X”) bolts for oversize holes created during repair or when original holes become worn.
• Aerospace Systems
  • Integration in satellite, rotorcraft, and defense equipment, taking advantage of high strength and corrosion resistance.
• Compliance & Quality Assurance
  • Ensures consistent quality in fastener supply chains by referencing critical industry standards and marking practices.

Related Standards

FprEN 6122 references and aligns with several key industry standards for aerospace fasteners and finishes:

• EN 2424: Marking of aerospace products
• EN 4473: Aluminium pigmented coatings for fasteners
• ISO 8080: Anodic treatment of titanium and titanium alloys
• ASTM B348: Titanium and titanium alloy bars and billets
• SAE AMS2700: Passivation of corrosion resistant steels
• NASM 8975: General specification for blind, high strength fasteners
• MIL-PRF-46010, SAE AS5272, SAE AS87132, DOD-L-85645: Approved lubricants and coatings
• SAE AMS4957, SAE AMS5687, SAE AMS5690, SAE AMS5737: Material and metallurgical requirements for bars, wire, and forgings

Practical Value

Adopting FprEN 6122 simplifies part selection and procurement for aerospace manufacturers and maintainers. Its standardized approach ensures:

• Consistent Interchangeability: Across platforms and repair operations, reducing inventory complexity.
• Enhanced Safety: Reliably maintains structural integrity under high load and adverse environmental conditions.
• Regulatory Compliance: Eases demonstration of conformity to European and international aerospace quality requirements.
• Future-proofing: Alignment with the latest material options and surface treatment technologies.

In summary, FprEN 6122 is essential for aerospace industry stakeholders seeking robust, consistent, flush-head blind bolting solutions, facilitating efficient production, maintenance, and safety assurance.

Standards Content (Sample)

SLOVENSKI STANDARD
01-oktober-2024
Aeronavtika - Slepa kovica, 130° ugrezna glava, visoka trdnost
Aerospace series - Blind bolt, 130° flush head, high strength
Luft- und Raumfahrt - Blindbolzen, 130° Senkkopf, hochfest
Série aérospatiale - Boulon aveugle, Tête fraisée 130°, haute résistance
Ta slovenski standard je istoveten z: prEN 6122
ICS:
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
prEN 6122
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2024
ICS 49.030.20 Will supersede
English Version
Aerospace series - Blind bolt, 130° flush head, high
strength
Série aérospatiale - Boulon aveugle, Tête fraisée 130°, Luft- und Raumfahrt - Blindbolzen, 130° Senkkopf,
haute résistance hochfest
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
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 6122:2024 E
worldwide for CEN national Members.

prEN 6122:2024 (E)
Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 5
4 Requirements . 5
4.1 Configuration, dimensions, tolerances, static strength, preload and spindle retention . 5
4.2 Grip range and mass . 5
4.3 Material, finish and lubrication . 5
4.4 First oversize . 5
5 Designation . 22
6 Marking . 22
7 Technical specification . 22

prEN 6122:2024 (E)
European foreword
This document (prEN 6122:2024) 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 prEN 6122:2005 .
This document includes the following significant technical changes with respect to prEN 6122:2005:
a) Figure 1 and Figure 2 updated (dimension Q removed);
b) dimension Q removed in Table 1 accordingly;
c) Table 1 and Table 3: Single values corrected and hole limits removed;
d) Table 5 and Table 6 updated according updated normative references and preferred options;
e) oversize “X” added in document.

Published by ASD-STAN, available at https://www.asd-stan.org.
prEN 6122:2024 (E)
1 Scope
This document specifies the configuration, dimensions, tolerances and mass of a stainless steel and
titanium blind bolt with 130° flush head for aerospace application.
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 2424:2008, Aerospace series — Marking of aerospace products
EN 4473, Aerospace series — Aluminium pigmented coatings for fasteners — Technical specification
ISO 8080, Aerospace — Anodic treatment of titanium and titanium alloys — Sulfuric acid process
ASTM B348, Standard Specification for Titanium and Titanium Alloy Bars and Billets
DOD-L-85645, Lubricant, Dry Film, Molecular Bonded
MIL-PRF-46010, Lubricant, Solid Film, Heat cured, Corrosion Inhibiting NATO Code – S-1738
NASM 8975, Fastener, Blind, High Strength, Installation Formed, Cres, Heat Resistant Steel and Titanium,
General Specification for
SAE AMS2700, Passivation of Corrosion Resistant Steels
SAE AMS4957, Titanium Alloy, Round Bar and Wire, 3Al-8V-6Cr-4Mo-4Zr, Consumable Electrode Melted
Solution Heat Treated and Cold Drawn
SAE AMS5687, Nickel Alloy, Corrosion- and Heat-Resistant, Wire 74Ni-15,5Cr-8,0Fe Annealed
SAE AMS5690, Steel, Corrosion and Heat Resistant, Wire, 17Cr-12N-2.5Mo (316), Solution Heat Treated
SAE AMS5737, Steel, Corrosion and Heat Resistant, Bars, Wire, Forgings, Mechanical Tubing, and Stock
for Forging and Heading 15Cr-25,5Ni-1,2Mo-2,1Ti-0,006B-0,30V (A286) Consumable Electrode Remelted,
1650 °F (899 °C) Solution and Precipitation Heat Treated
SAE AS5272, Lubricant, Solid Film; Heat Cured, Corrosion Inhibiting Procurement Specification
SAE AS87132, Lubricant, Cetyl Alcohol, 1-Hexadecanol, Application to Fasteners

Published by American Society for Testing and Materials (ASTM International), available at:
https://www.astm.org/.
Published by Department of Defense (DoD), available at: https://assist.dla.mil/.
Published by Aerospace Industries Association (AIA), available at: https://www.aia-aerospace.org/.
Published by Society of Automotive Engineers (SAE), available at: https://www.sae.org/.
prEN 6122:2024 (E)
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp/
— IEC Electropedia: available at https://www.electropedia.org/
4 Requirements
4.1 Configuration, dimensions, tolerances, static strength, preload and spindle retention
The configuration, dimensions, tolerances, static strength, tensile preload and spindle retention shall
conform to Figure 1, Figure 2, Table 1 and Table 2.
4.2 Grip range and mass
Grip range and mass shall be according to Table 3 and Table 4.
4.3 Material, finish and lubrication
Material, finish and lubrication shall be according to Table 5 and Table 6.
4.4 First oversize
First oversize “X” shall be in CRES and according to Table 7, Table 8, Table 9 and Table 10.
prEN 6122:2024 (E)
a) Bolt configuration
b) Serrated pin geometry
prEN 6122:2024 (E)
Key
1 marking, see Clause 6
2 serrated pin
3 locking collar
4 0,005 Ref. crown height
5 grip
6 sleeve
7 shifting anvil
8 drive washer
Diameter of pin head shall not exceed “⌀D” max
Fasteners are supplied with shifting anvil/drive washer of manufacturer’s option. The shifting
anvil/drive washer is not part of the installed fastener.
Optional configuration.
Figure 1 — Configuration, dimensions

Key
1 grip
Blind side head may be installed on 7° max. slope.
Figure 2 — Typical installation
prEN 6122:2024 (E)
Table 1 — Dimensions and tolerances, CRES and titanium
Dimensions in mm (inch)
Diameter code
05 06 07 08 09 10
Theor.
8,43 9,80 10,57 12,88 13,66 16,13
⌀A
(0,332) (0,386) (0,416) (0,507) (0,538) (0,635)
Ref.
⌀A2 min. 7,52 8,81 9,47 11,76 12,55 14,66
(0,296) (0,347) (0,373) (0,463) (0,494) (0,577)
0,99 1,09 1,09 1,45 1,45 1,91
B Ref.
(0,039) (0,043) (0,043) (0,057) (0,057) (0,075)
0,478 0,488 0,627 0,602 0,754 0,704
0,376 0,386 0,561 0,500 0,696 0,638
H Gage HT
(0,018 8) (0,019 2) (0,024 7) (0,023 7) (0,029 7) (0,027 7)
(0,014 8) (0,015 2) (0,022 1) (0,019 7) (0,027 4) (0,025 1)
7,193 8,311 8,420 10,973
10,973 13,688
7,188 8,306 8,415 10,968 10,968 13,678
⌀W Gage dia.
(0,283 2) (0,327 2) (0,331 5) (0,432 0) (0,432 0) (0,538 9)
(0,283 0) (0,327 0) (0,331 3) (0,431 8) (0,431 8) (0,538 5)
±0,03 4,14 5,03 5,74 6,58 7,31 7,88
⌀D
(±0,001) (0,163) (0,198) (0,226) (0,259) (0,288) (0,310)
±0,13 9,53 9,53 9,53 9,53 9,53 11,13
a
⌀J
(±0,005) (0,375) (0,375) (0,375) (0,375) (0,375) (0,438)
±1,52 3,56 4,06 4,45 4,83 5,33 6,09
N
(±0,060) (0,140) (0,160) (0,175) (0,190) (0,210) (0,240)
3,05 3,81 4,14 4,83 5,23 5,61
⌀D max.
(0,120) (0,150) (0,163) (0,190) (0,206) (0,221)
2,16 2,79 3,17 3,66 4,06 4,82
⌀D max.
(0,085) (0,110) (0,125) (0,144) (0,160) (0,190)
7,62 8,13 8,89 9,40 10,92 12,70
b
P max.
(0,300) (0,320) (0,350) (0,370) (0,430) (0,475)
5,66 6,86 7,82 9,02 9,96 10,41
⌀P min.
(0,223) (0,270) (0,308) (0,355) (0,392) (0,410)
0,64 0,64 0,76 0,76 0,76 1,01
R max
(0,025) (0,025) (0,030) (0,030) (0,030) (0,040)
5,89 7,42 8,17 9,17 10,16 11,22
S max.
(0,232) (0,292) (0,322) (0,361) (0,400) (0,442)
±0,76 20,32 21,08 22,60 24,77 26,67 26,67
J
(±0,030) (0,800) (0,830) (0,890) (0,975) (10,050) (10,050)
prEN 6122:2024 (E)
Diameter code
05 06 07 08 09 10
Number
of
J 18 19 20 20 20 20
serrations
min.
±0,76 1,52 1,78 2,28 2,29 2,29 2,29
X
(±0,030) (0,060) (0,070) (0,090) (0,090) (0,090) (0,090)
0,13 0,13 0,13 0,13 0,13 0,13
E min.
(0,005) (0,005) (0,005) (0,005) (0,005) (0,005)
0,33 0,33 0,33 0,33 0,33 0,33
C Ref.
(0,013) (0,013) (0,013) (0,013) (0,013) (0,013)
±0,05 0,81 0,81 0,79 0,81 0,79 0,79
C
(±0,002) (0,032) (0,032) (0,031) (0,032) (0,031) (0,031)
F ±5° 45° 45° 45° 45° 45° 45°
G ±5° 30° 30° 30° 30° 30° 30°
a
Diameter code 05 is also available with reduced diameter shifting anvil/drive washer
[(7,93 ± 0,13) mm/(0,312 ± 0,005) inch]. See part number examples.
b
In the length of P, ⌀D may be 0,05 mm (0,002 inch) undersize.
Table 2 — Static strength (installed), tensile preload, spindle retention
Strength in kN (lbf)
Diameter Single shear Tensile strength Tensile preload Spindle retention
code strength
min. min. min. min.
CRES Ti CRES Ti CRES Ti CRES Ti
8,807 8,807 4,671 3,603 0,467 0,544 2,335 1,824
(1 980) (1 980) (1 050) (810) (105) (121) (525) (410)
13,011 13,011 6,672 5,605 0,667 0,841 3,336 2,804
(2 925) (2 925) (1 500) (1 260) (150) (189) (750) (630)
17,036 8,851 0,885 4,337
07 — — — —
(3 830) (1 990) (199) (975)
22,241 22,241 11,565 8,407 1,157 1,263 5,783 4,204
(5 000) (5 000) (2 600) (1 890) (260) (284) (1300) (945)
27,623 14,345 1,436 7,117
09 — — — —
(6 210) (3 225) (323) (1 600)
32,027 16,680 1,668 8,340
10 — — — —
(7 200) (3 750) (375) (1 875)
prEN 6122:2024 (E)
Table 3 — Grip range
Dimensions in mm (inch)
Diameter code
05 06 07 08 09 10
Grip Underlap Grip Range Overlap L K L K L K L K L K L K
length
min. min. min. max. max. Ref. max. Ref. max. Ref. max. Ref. max. Ref. max. Ref. max.
code
only 05 06 dia. to  05 dia. to
dia. 10 dia. 10 dia.
a
2,39 3,99 4,39 8,53 12,09 9,02 13,23
02 — — — — — — — — — —
(0,094) (0,157) (0,173) (0,336) (0,476) (0,355) (0,521)
b
3,71 3,56 3,96 5,59 5,99 10,11 13,69 10,59 14,81 12,29 16,38 12,17 16,38 13,67 18,39
03 — —
(0,146) (0,140) (0,156) (0,220) (0,236) (0,398) (0,539) (0,417) (0,583) (0,484) (0,645) (0,479) (0,645) (0,538) (0,724)
5,31 5,16 5,56 7,16 7,57 11,68 15,29 12,19 16,41 13,49 17,58 13,74 17,96 14,86 19,58 15,44 20,45
(0,585)
(0,209) (0,203) (0,219) (0,282) (0,298) (0,460) (0,602) (0,480) (0,646) (0,531) (0,692) (0,541) (0,707) (0,771) (0,608) (0,805)
6,88 6,73 7,14 8,76 9,17 13,28 16,87 13,77 17,98 15,06 19,15 15,34 19,56 16,43 21,16 17,04 22,05
(0,271) (0,265) (0,281) (0,345) (0,361) (0,523) (0,664) (0,542) (0,708) (0,593) (0,754) (0,604) (0,770) (0,647) (0,833) (0,671) (0,868)
8,48 8,33 8,74 10,34 10,74 14,86 18,47 15,37 19,58 16,66 20,75 16,92 21,13 18,03 22,76 18,62 23,62
(0,334) (0,328) (0,344) (0,407) (0,423) (0,585) (0,727) (0,605) (0,771) (0,656) (0,817) (0,666) (0,832) (0,710) (0,896) (0,733) (0,930)
10,06 9,91 10,31 11,94 12,34 16,46 20,04 16,94 21,16 18,24 22,33 18,52 22,73 19,61 24,33 20,22 25,22
(0,396) (0,390) (0,406) (0,470) (0,486) (0,648) (0,789) (0,667) (0,833) (0,781) (0,879) (0,729) (0,895) (0,772) (0,958) (0,796) (0,993)
11,66 11,51 11,91 13,51 13,92 18,03 21,64 18,54 22,76 19,84 23,93 20,09 24,31 21,21 25,93 21,79 26,80
(0,459) (0,453) (0,469) (0,532) (0,548) (0,710) (0,852) (0,730) (0,896) (0,781) (0,942) (0,791) (0,957) (0,835) (1,021) (0,858) (1,055)
13,23 13,08 13,49 15,11 15,52 19,63 23,22 20,12 24,33 21,41 25,50 21,69 25,91 22,78 27,51 23,39 28,40
(0,521) (0,515) (0,531) (0,595) (0,611) (0,773) (0,914) (0,792) (0,958) (0,843) (1,004) (0,854) (1,020) (0,897) (1,083) (0,921) (1,118)
14,83 14,68 15,09 16,69 17,09 21,21 24,82 21,72 25,93 23,01 27,10 23,27 27,48 24,38 29,11 24,97 29,97
(0,584) (0,578) (0,594) (0,657) (0,673) (0,835) (0,977) (0,855) (1,021) (0,906) (1,067) (0,916) (1,082) (0,960) (1,146) (0,983) (1,180)
16,41 16,26 16,66 18,29 18,69 22,81 26,39 23,29 27,51 24,59 28,68 24,87 29,08 25,96 30,68 26,57 31,57
(1,022)
(0,646) (0,640) (0,656) (0,720) (0,736) (0,898) (1,039) (0,917) (1,083) (0,968) (1,129) (0,979) (1,145) (1,208) (1,046) (1,243)
prEN 6122:2024 (E)
Diameter code
05 06 07 08 09 10
Grip Underlap Grip Range Overlap L K L K L K L K L K L K
length
min. min. min. max. max. Ref. max. Ref. max. Ref. max. Ref. max. Ref. max. Ref. max.
code
only 05 06 dia. to  05 dia. to
dia. 10 dia. 10 dia.
18,01 17,86 18,26 19,86 20,27 24,38 27,99 24,89 29,11 26,19 30,28 26,44 30,658 27,56 32,28 28,14 33,15
(0,709) (0,703) (0,719) (0,782) (0,798) (0,960) (1,102) (0,980) (1,146) (1,031) (1,192) (1,041) (1,207) (1,085) (1,271) (1,108) (1,305)
19,58 19,43 19,84 21,46 21,87 25,98 29,57 26,47 30,68 27,76 31,85 28,04 32,26 29,13 33,86 29,74 34,75
(0,771) (0,765) (0,781) (0,845) (0,861) (1,023) (1,164) (1,042) (1,208) (1,093) (1,254) (1,104) (1,270) (1,147) (1,333) (1,171) (1,368)
21,18 21,03 21,44 23,04 23,44 27,56 31,17 28,07 32,28 29,36 33,45 29,62 33,83 30,73 35,46 31,32 36,32
(0,834) (0,828) (0,844) (0,907) (0,923) (1,085) (1,227) (1,105) (1,271) (1,156) (1,317) (1,166) (1,332) (1,210) (1,396) (1,233) (1,430)
22,76 22,61 23,01 24,64 25,04 29,16 32,74 29,64 33,86 30,94 35,03 31,22 35,43 32,31 37,03 32,92 37,92
(0,896) (0,890) (0,906) (0,970) (0,986) (1,148) (1,289) (1,167) (1,333) (1,218) (1,379) (1,229) (1,39
...