DIN 938 is a German industrial standard published in 2012-12 that specifies double-end stud bolts with a tap-end thread length equal to 1d (one nominal diameter). The standard covers sizes M3 through M68, with thread tolerance class 6g per ISO 965-1 and property classes 5.6, 8.8, and 10.9 per DIN EN ISO 898-1. DIN 938 is one of four sister standards in the German double-end stud series, differentiated by tap-end length: DIN 938 (1d), DIN 939 (1.25d), DIN 835 (2d), DIN 940 (2.5d). All four share identical body diameter, thread pitch, and tolerance class. Inspection certificates are issued per EN 10204 type 3.1 (mill certificate) or type 3.2 (third-party witnessed). TorqBolt manufactures DIN 938 stud bolts qualified to NORSOK M-650, PED 2014/68/EC, NACE MR0175 / ISO 15156, and ISO 9001:2015.
DIN 938 Standard
Specification includes dimensions and technical
delivery conditions of studs intended for use mainly in stainless steel,
carbon steel and alloy steel with a comparatively lower demand in brass as
well.
Length = 1.5d
M3-M52
Coarse & Fine Threads
Tap End Studs
DIN 938 standard
specifies dimensions and technical delivery conditions of studs intended for use
mainly in stainless steel, carbon steel and alloy steel with a comparatively lower
demand in brass as well. Din 938 Double End Stud Bolts have a thread length
engagement equal to 1d on stud end and the nut end length varies as per the
application. Double End Stud bolts can be manufactured as per DIN 938
Specification with metric thread M3 to M52 and metric fine thread M8x1 to
M52x3. As specified in DIN 267-2, the tap end studs shall be produced to tolerance
Sk6 as in DIN 13-51, unless the stud is designated without interference - Fit Thread
(Fo) or Sn4.
When ordering DIN 938 double end studs, the correct dimension is diameter x
nominal length (excluding the tap end b1).
For example, with a stud measuring M10X75 (the diameter(d) = 10mm and nominal
length(l) = 75 mm where the thread length on the metal end (tap end) b1 = 10 mm; the
overall length of the stud is 75 + 10 = 85 mm. The thread length on the nut end b2
varies depending on the length of the stud.
DIN 938 vs DIN 939 vs DIN 835 vs DIN 940
DIN 938 belongs to a four-standard family for double-end stud bolts. The four standards differ only in tap-end thread engagement length (b1). Body diameter, thread pitch, nut-end length, and tolerance class are identical across the four.
Standard
Tap-end length (b1)
Typical use
DIN 938
1 × d (short)
Hardened steel base material
DIN 939
1.25 × d
General industry standard
DIN 835
2 × d
Softer metals (aluminum, cast iron)
DIN 940
2.5 × d (long)
Lowest-strength substrate, max engagement
DIN 938 Normative References
Documents that are cited on this website in part or as a whole,
are indispensable for the application of this website. For dated references, only the
edition cited applies. For undated references the latest edition of the referenced
document (including any amendments) is available for download on the left side bar.
DIN 938 is a German industrial standard for double-end stud bolts with a tap-end thread length equal to 1d (one nominal diameter). The standard covers sizes M3 through M68 in carbon, alloy, stainless, duplex, and nickel-alloy materials.
What is the difference between DIN 938 and DIN 939?
DIN 938 has a tap-end thread length of 1d. DIN 939 has a tap-end thread length of 1.25d. Both standards share the same body diameter, thread pitch, nut-end length, and tolerance class. DIN 938 is specified where the base material is hardened steel; DIN 939 is the general-industry default.
What property classes are available for DIN 938 stud bolts?
For sizes M3 through M39, DIN 938 stud bolts are supplied in property classes 5.6, 8.8, and 10.9 per DIN EN ISO 898-1. For sizes above M39, property class is specified by appointment.
What thread tolerance does DIN 938 use?
DIN 938 uses thread tolerance class 6g for the nut-end and Sk6 (with fundamental deviation Fo) or Sn4 for the tap-end, per DIN ISO 965-1.
What inspection certificates are available for DIN 938 stud bolts from TorqBolt?
TorqBolt supplies DIN 938 stud bolts with EN 10204 type 3.1 (mill certificate, issued by the manufacturer) or type 3.2 (third-party witnessed by a notified body). NORSOK M-650 qualification certificates and NACE MR0175 / ISO 15156 sour-service compliance certificates are available on request.
