Flat nut DIN 439 M2.5 (10pcs)

Small detail, big difference in assembly

The flat nuts of standard DIN 439 are distinguished by their particularly low profile compared to a standard hex nut. This makes them the usual choice when there are space restrictions or when one wants to reduce the weight of the assembly without sacrificing the safety of the joint. In the M2.5 format, they fit into the range of fine screws that are so prevalent in the preparation and maintenance of slot cars, chassis, motor mounts, and a multitude of static modelling assemblies.

Main features

• Standard: DIN 439 — flat hex nut (medium height).
• Metric: M2.5.
• Content: pack of 10 units.
• Reference: CXM381.
• Reduced profile, ideal where the space between parts is limited.

Function and applications

The DIN 439 standard defines a nut whose height is approximately half that of the standard DIN 934 nut. This low profile is particularly useful in situations where two components are very close to each other, or when it is necessary to secure an element without the nut protruding from the assembly. In the world of slot and modelling, some common uses include:

• Securing motor mounts, chassis, and transmission elements in prepared chassis.
• Locknut in fine adjustments where it is necessary to lock the position without adding height.
• Mounting 3D printed or machined parts where M2.5 screws are the most widespread.
• Static modelling projects and dioramas where small metric screws are part of the detail or internal structure.

Assembly and usage recommendations

As it is a low-profile nut, its resistance to torque is lower than that of a standard nut of the same metric. Therefore, it is advisable to use it in applications where the final tightening is not excessive, or to use it as a locknut alongside a conventional nut to secure the position without the risk of loosening. For handling, it is recommended to use a spanner or appropriate tool for M2.5, avoiding forcing the hexagonal head.

Frequently asked questions

What is the difference between a DIN 439 nut and a DIN 934 nut?

The DIN 934 is the standard hex nut, with full height. The DIN 439 has approximately half the height, making it flatter and lighter, although with lower resistance to torque. It is used when space is limited or as a locknut.

What metric is this nut designed for?

This reference (CXM381) corresponds to the M2.5 metric, one of the most common in fine screws for slot, modelling, and electronics.

How many units are included in the pack?

The pack includes 10 units of DIN 439 flat nut M2.5.

Can I use it as a locknut?

Yes, it is one of its most common uses: it is placed alongside a standard nut to lock the position and prevent it from loosening due to vibration, which is very common in slot assemblies subjected to track vibrations.

What type of screw is it compatible with?

With any screw or threaded rod of M2.5 metric with standard pitch (0.45 mm according to ISO standard), regardless of the material or finish of the screw.

The CXM381 is a pack of 10 DIN 439 flat (thin) hex nuts in M2.5 metric thread. These low-profile nuts are widely used in slot car preparation, static model assembly, and precision hobby builds where standard-height nuts would not fit. Compatible with any M2.5 standard-pitch screw or threaded rod, they are a must-have in any slot car workshop or modeller's parts drawer.