This is a two part stirrer, the stirrer itself and the shaft. You'll need an m5 bolt (40mm or so) to screw the stirrer into the shaft. You can customize the shaft length by non-uniformly scaling the X axis longer. I printed the shaft diagonally on my print bed to maximize the length.

I designed it in two parts so that the shaft could be printed flat to avoid weakness at the layer lines, but that also made it scalable, so double win! :)

This is designed also to be printable without supports.

I printed with:

• 3 perimeters
• 40% infill

I tapped the shaft with an m5 tap to make the screw easier to turn in (though it probably would've tapped itself.)

Scaling Tip

Another Printables user reported that they were able to successfully scale to 3/5th size for M3; Nice hack. :)