The picks that I used for these handles are the ones in a credit card form factor from Lock Cowboy, and where included in a kit with a training lock brought up on amazon. With these handles and some sanding on the metal edges of the picks themselves they actually make a quite descent addition to your tool collection.

Used https://www.thingiverse.com/thing:1123385 by Uncle as inspiration for this but I decided to make some modifications to the design of my own:

First off its a bit longer. 82mm in total. The width is the same 12mm and the height is 4mm.

I also added a one perimeter edge support that you will have to remove post-print. This is because the printer don’t like printing overhangs in a circular motion. You can use either a thin saw blade or a knife to remove it. Then just insert the pick and clear the opening, and if needed, ad a drop of superglue and put together.

The cavity inside has the modelled dimensions 39.5mm depth and means that the wide metal part of my picks will not protrude. Cavity is modelled with a width of 8.2 mm and printed this will make it a snug fit for 8mm wide pick. Height is 0.8 mm and will thus fit a pick with a thickness of 0.6 mm.

Included stl and fusion file in case you need to modify this to further fit your needs.