What screw and mounting options work best for heat sinks?

Mounting a heat sink incorrectly can lead to thermal failure. Many overlook screw compatibility and torque. That can damage components or reduce heat transfer.

Most heat sinks support machine screws like M2–M4, can be mounted using screws, clips, or push-pins, and often offer customizable holes or threaded inserts. Torque must be controlled to avoid damage.

To choose the right mounting approach, I always look at the mechanical, thermal, and maintenance needs. Let’s explore what fasteners and mounting options work, and how to avoid common mistakes.

What screw types are compatible with your heat sinks?

Mounting a heat sink using the wrong screw can strip threads or crush the base. That risks poor contact with the chip and early failure.

Heatsinks typically support metric (M2, M3, M4) or imperial (#4-40, #6-32) screws, with head types like pan, flat, or socket. Both self-tapping and machine screws may be used depending on design.

Common screw types used in heat sink applications

I usually recommend metric screws when possible, especially M3 or M4. For heavier modules or deeper threaded holes, M4 works best. If you’re designing around high torque, M4 provides more strength. In most extruded aluminum heatsinks, tapped holes accept these screws easily.

Which mounting methods are supported by your heat sink designs?

Poor mounting leads to bad thermal contact. Spring clips and push pins may be easier to install but can fail under vibration. Screws hold better but need correct torque.

Heatsinks can be mounted using screws, spring clips, push pins, adhesive, rivets, or standoffs, depending on size, weight, and application.

Table: Mounting methods and trade-offs

For small board-level heatsinks, push-pins and clips often suffice. Larger heat sinks, especially those mounted to enclosures or modules, require screws or standoffs. Sometimes, a hybrid method like screws + thermal tape improves reliability.

Do you offer threaded holes or press-fit inserts?

Threaded holes make mounting easy, but if the heatsink wall is too thin, they can strip. In those cases, I use inserts.

Yes, we support tapped holes, press-fit inserts, and clinch fasteners like PEM nuts or captive screws, depending on heatsink thickness and load.

Hole types and threaded insert options

For M3 or M4 holes, I tap directly into aluminum if the wall thickness is at least 3 mm. If it’s thinner or torque is high, I add press-fit inserts. Inserts resist stripping and last longer when mounted multiple times.

Can screw hole size and placement be customized?

If screw holes are in the wrong place, mounting fails. I always allow hole customization during heatsink design to match your layout.

Yes, you can customize screw hole size, thread type, depth, placement, and tolerance to fit your specific mounting needs.

Typical screw hole customizations

I use 3D CAD to ensure holes avoid fins, maintain wall strength, and line up with the customer’s mounting pattern. I also use bosses under the holes for strength. Clearance holes are usually slightly oversized (e.g. 3.4 mm for M3 screw). This allows some tolerance during installation.

What torque specifications apply to mounting your heat sinks?

Too much torque breaks parts. Too little and the heatsink wobbles. I always follow spec ranges to avoid stress.

Torque limits vary by screw size and heatsink material. For example, M3 screws often use 0.5–0.7 Nm, and M4 screws 1.6–2.0 Nm.

Reference torque values for screw sizes

Always use torque-controlled tools. I apply torque in two steps to let the TIM (thermal interface material) settle. Washers help distribute load and prevent loosening. I avoid over-torquing especially near thin fins or small modules.

Závěr

Mounting heatsinks correctly requires matching the screw type, thread, hole design, and torque. With the right combination, you ensure strong contact, better heat transfer, and safer operation.