INDUSTRIAL DESIGNERS: self-tapping vs machine screws

Going with something light and simple today. ​ ​ For those out there designing plastic components and not sure what type of assembly hardware to use. Here’s a quick tip.

Self-tapping screws have a coarse thread and often a notch detail which cuts into plastic. Fast, cheap, done. Perfect when nobody's opening this thing again. Cheaper consumer tech that won’t need to get serviced - go with self-tapping.

Machine screws have a fine thread and need pre-formed threads or inserts in the plastic. They are more expensive, and require more steps. But are capable of being taken apart and reassembled easily. Self-tap screws will strip on second disassembly and make repair impossible.

How to decide. Think about the product’s lifecycle.

Will anyone be servicing this product? Or replacing the battery? Swapping parts? Machine screws with inserts. Self-tappers strip on second disassembly.

Sealed unit only used until it dies? Save time, save money - Self-tapping.

I can’t tell you what to use, but please do try to design for serviceability when possible. Right to repair, and sustainability matters. The world doesn't need more throwaway products that can't be fixed.

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