I'm watching a YouTube video about making an armchair, and at the 01:27 mark they show this metal bits that looks like short hollow nails with tiny throwingstars for a head. They're hammered into the wood and seem to provide threads for screws to fasten into. The shape of their heads seems to be meant to allow further reinforcement using nails or other screws. What are they called?

The shape of the thing.

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    That's a type of threaded insert, one of a number of different styles. Specifically these are tee nuts. They work exactly as you describe, adding a position for machine screws or bolts to be turned into. BTW in many applications a hole in the wood can be used as-is, with threads cut or forced into the interior wall, and still provide long service. This is especially true of hardwoods, but even in softwoods it can work if done carefully. And the threading can be further strengthened with a little glue if desired/needed.
    – Graphus
    Commented Jun 28, 2020 at 7:20
  • 1
    @Graphus -- cut and paste that as an answer... Commented Jun 28, 2020 at 15:38

1 Answer 1


That is called a Tnut.

enter image description here

Tnut search.

It is similar to a threaded insert but it is pressed into the wood and has little points that grab the wood and keeps it from rotating when you thread a bolt into it.

A threaded insert as threads on the outside and is threaded into the wood like a screw.

enter image description here

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    I will add that tee nuts come in many sizes and types. Some have a flanged base with holes, rather than prongs, for using small brads or screws to secure. +1 Commented Jun 28, 2020 at 22:48
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    Just to also add, not all threaded inserts are threaded on the outside. Some are a press fit, or intended to be glued in.
    – Graphus
    Commented Jun 29, 2020 at 7:10

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