Alternate connector for the open hardware 3D printable STEMFIE construction set

This threaded hole insert fits into the beam holes (https://www.stemfie.org/parts) and allows to use the threaded fasteners in more flexible ways (cf. model pictures).

The part appears brittle but prints well with standard settings in PLA and PTEG is surprisingly strong.

For more information on STEMFIE, see https://www.stemfie.org/ and https://makerworld.com/en/@Stemfie3D