Info:

• for simple keys with round base
• for keys with dimensions of the round part:
  • diameter: 23 mm (or less)
  • thickness: 2,3 mm (or less)
• designed to be tight, so it does not slip away
• in Blender you can easily use different text (if you are familiar with this program)
  • there is set mirror modifier, so the text is on both sides mirrored and at the center
    • see below for details

Other key base dimensions or shapes:

• can be just scaled for base with different size of round base (scale X+Z)
• also you can scale it for elyptical base (scale X axis more)
• or different thickness (scale Y)

Print instructions:

• easy print, no supports
• the wall is thick for exactly 2 perimeters (for 0.4mm nozzle)
• i have used 0.2mm high layers, but you can set less in slicer for nicer results

Texts:

• if you want own text on the print, negative text volume should be deep ½ of the wall thickness (so there will remain 1 perimeter for the rest of the wall)
• How to in Blender:
  • check my model in blender, locate the element “TEXT”, edit it & insert your own text
  • then you need to convert it to mesh (Object → Convert → Mesh)
  • locate element “sides”, locate its “Modifier properties” (tool icon), locate “Boolean text” modifier and set it to field “Object” → select “TEXT” in list box
  • hide “TEXT” element and you should see given text as negative volume on both sides
  • hit A, F4, E, T (in dialog check Selected only) → for exporting STL 
• Other possibilites:
  • or create text STL in some other program and use it in slicer directly (put it in the wall to the half of its thickness) as negative volume