Metric Screws ø4.25 x 7.2mm Cone Head

Millimetric precision for every assembly: metric screw ø4.25 x 7.2mm with conical head

In the world of slot racing and competition modelling, the smallest details are what separate a mediocre assembly from a truly refined one. The screw BRM-S133B1 —metric, diameter ø4.25 mm and length 7.2 mm, with a conical head— meets this requirement exactly: a fastening element that sits flush, distributes the load evenly, and does not add unnecessary volume where space is critical.

Features and function

• Diameter: ø4.25 mm
• Length: 7.2 mm
• Conical head: allows for embedding in the material, leaving the mounting surface smooth and without protrusions
• Reference: BRM-S133B1

The conical head is the geometry of choice when the screw needs to be flush or slightly recessed relative to the surface. This is especially relevant in slot car chassis, where any protrusion can interfere with the body, wiring, or the guide rail itself.

Assembly and preparation

To make the most of this type of screw, it is advisable to properly prepare the housing in the receiving material. If the chassis or the fastening piece does not have a pre-countersink, it is advisable to create one with the appropriate drill before inserting the screw. This way, the conical head sits on its entire surface, avoiding localized stresses and ensuring uniform tightening.

Always use the correct tool —a screwdriver with the exact size tip— to avoid damaging the profile of the head. In delicate chassis parts, apply the right torque: over-tightening can deform the housing or break the threading.

Ideal for…

• Club preparers and drivers working with BRM chassis or similar who need to replenish specific screws.
• Slot enthusiasts making modifications or repairs to their cars and requiring exact measurements.
• Model builders and diorama creators using precision screws in their assemblies.

Aspects to consider

Always verify that the dimensions (ø4.25 x 7.2 mm) and the type of thread are compatible with the mounting point of your chassis before placing the order. Precision screws are not interchangeable between different standards, and a millimetre difference can mean that the fit is not correct.

Frequently asked questions

What type of chassis is this screw designed for?

The reference BRM-S133B1 belongs to the BRM screw catalogue. It is the recommended option for assemblies and repairs on chassis and components of this brand, although its use can extend to any application requiring a metric screw ø4.25 x 7.2 mm with a conical head.

What advantage does the conical head offer over a flat or cylindrical head?

The conical head allows the screw to be embedded in the material, leaving the mounting surface free of protrusions. This is essential in applications where space is limited or where any protrusion could interfere with other elements of the assembly.

How many units are included in the package?

The information on units per package is indicated on the product sheet and at the time of purchase. If you have any doubts, you can consult us before placing the order.

Do I need any special tools to install this screw?

No special tools are required, but it is important to use a screwdriver with the exact size tip to avoid damaging the head. If the housing is not countersunk, it is advisable to prepare it beforehand with the appropriate drill.

The BRM-S133B1 is a metric countersunk screw measuring ø4.25 x 7.2mm, designed for precision assembly in slot car chassis and modelmaking projects. Its conical head allows a flush fit, making it a go-to fastener for BRM chassis repairs, slot car preparation, and fine-detail static model builds. Available at Ministry of Hobby, your specialist in slot, scale models, and high-end collectibles.