2UDS STOPPER M2.5

Two M2.5 stoppers that make a difference in assembly detail

In the preparation of a slot car or in the assembly of any precision mechanical set, the small fastening elements dictate whether the final result is solid and repeatable or, on the contrary, if play and misalignments appear that ruin the previous work. The M2.5 stoppers from reference CXM117 meet this need exactly: to keep each component in its position, without unwanted movement and with the assurance of a reliable fit.

Function and performance

A stopper —also called a shaft stop or locking nut— acts as a mechanical retention element. When correctly placed on an M2.5 shaft or screw, it prevents the longitudinal movement of the piece to which it is applied. In the context of slot racing and precision modelling, this translates into:

• Control of axial play in rear and front axles.
• Fixing of crowns, pinions and other rotating elements in their optimal position.
• Stability in assemblies where vibration or continuous rotation could displace components.

Compatibility and applications

The M2.5 metric thread is one of the most widely used standards in small-format fasteners used in slot racing, static models, and modelling in general. This pack of 2 units covers both the initial installation and the possibility of having a spare unit on hand, something that any experienced preparer appreciates having in their workshop drawer.

They are particularly useful in tuning work on chassis from different brands, where the M2.5 metric frequently appears in axles, motor mounts, and anchoring points for brackets.

Assembly and preparation

The assembly of an M2.5 stopper does not require specialized tools beyond a wrench or screwdriver suitable for the specific format of the stopper. It is advisable to adjust it without over-tightening to avoid stressing the shaft thread, and always check that the final position does not generate unwanted friction with other nearby moving elements.

Common mistakes

• Over-tightening: this can damage the shaft thread or deform the stopper itself, especially in lightweight materials.
• Confusing the metric: an M2.5 stopper is not interchangeable with M2 or M3; always verify before assembly.
• Forgetting the correct torque: in parts that work with continuous vibration, an additional fixing point (low-strength thread lock) can be a good complementary practice.

Frequently asked questions

What exactly is the purpose of a stopper in the assembly of a slot car?

The stopper acts as a mechanical stop on a shaft or screw: it prevents the piece from moving longitudinally during operation, ensuring that crowns, wheels, and other rotating elements remain in the adjustment position defined by the preparer.

Why does this pack include 2 units?

Many assemblies require a stopper on each side of a piece (for example, to centre an element on a shaft), so 2 units is the minimum functional quantity for a complete job. Additionally, having spare units prevents downtime during a preparation session.

Is it compatible with any 2.5 mm shaft?

The M2.5 stopper is designed for a 2.5 mm metric thread. Before use, it is advisable to confirm that the shaft on which it will be mounted indeed has M2.5 thread and not a similar diameter from another standard, as the difference may be minimal but sufficient for it not to seat correctly.

Do I need any special tools to install it?

No. A wrench or fine-nose pliers suitable for the size of the stopper is sufficient. The important thing is to apply the right torque: firm but without forcing the thread.

The CXM117 pack includes 2 M2.5 stoppers, essential fastening elements for slot car preparation, scale model assembly and precision hobby builds. Designed to secure axles, gears and motor mounts in place, these M2.5 thread stoppers are a must-have for any workbench toolkit. Compatible with standard M2.5 metric threads widely used across slot car brands and static model kits.

Information not found

It has not been possible to confirm the manufacturer or brand of origin for this reference (CXM117) based on the available information. If you have more data about the brand or material of the stopper, we can expand and specify this sheet.