This is (yet another) holder for the 50kg load cells commonly available.

https://www.sparkfun.com/products/10245

The recess in the holder has been sized for a press-to-fit install of the load cell. Just snap it into place.

The internal space of the holder allows the inner plate to flex downwards with load: this is what you want, as it allows the strain gauges to work correctly.

You'll typically use 4 load cells to build a weight scale, along with some sort of differential amplifier and A/D conversion (E.g. HX711 chip).

The design is parameteric - and I've included the source if you wish to modify it.

Note: This is not OpenSCAD. It's a program written in Go. The main library and code examples can be found here:

https://github.com/deadsy/sdfx

About Go: https://golang.org/