Summary

I recommend printing this instead: https://www.thingiverse.com/thing:2783459

Simple Kirkland brand detergent adapter for Laundry Detergent Cup Drain by davwilso https://www.thingiverse.com/thing:2748680

I recommend an o-ring or rubber band between the drain and the adapter in order to create a good seal.

Print Settings

Rafts:

Yes

                                            <p class="detail-setting supports"><strong>Supports: </strong>                     <div><p>No</p></div></p>                                                                                <p class="detail-setting resolution"><strong>Resolution: </strong>                     <div><p>0.2</p></div></p>                                                                                <p class="detail-setting infill"><strong>Infill: </strong>                     <div><p>25</p></div></p>

How I Designed This

For the kirkland cap side of the adapter, I used Dan Kirshner's OpenSCAD threads library similar to the thinggy here, but I use a bigger thread size.

metric_thread(
internal=true,
groove=true,
thread_size=2,
square=false,
pitch=5,
diameter=32.9,
length=10 );

Then I stuck a cylinder with diameter of 38.8 around the resulting object and subtracted the object from the cylinder.

Kirkland detergent adapter for laundry soap holder