Apparently the plastic pulls that came with my window blinds are quite tasty, as my dogs chewed them all up (see photos).

It's a simple matter to design and print replacements - just make something with a hole in it. Attach it by poking the cord through and then putting a knot in it so it won't pull back out. However, I had quite a few of these to replace, and I didn't want to have to un-knot the cord (or cut off the existing knot), and then re-tie the knots. Instead, I designed these two-piece pulls.

The photos show the pull printed in PLA in both yellow and glow-in-the-dark filament.

Assembly

The main body of the pull has a fairly large hole, so the already knotted cord can fit through it. Once that is done, the cord is fitted into the slot in the plug piece, and the plug is pulled into the main body with the cord. 

Note that the plug has a slight taper - be sure to insert the narrower end into the pull first.

Print Instructions

Print in PLA using the gcode or 3mf files provided. In general :

• 0% infill
• 2 perimeters 

I tried printing with both 0.2mm and 0.3mm layer heights, but did not see much difference in appearance, and of course the 0.3mm layer height prints much faster.

I prepared the knob STL in three different versions

• plain (I couldn't get this to print reliably without using a brim; I found removing the brim annoying)
• ears
• tab

The “ears” STL has two small ears on the bottom to promote bed adhesion; these can be easily cut off with a razor knife after printing. I found this version to be easier to trim than the “tab” version.

The “tab” version has an internal tab for bed adhesion. The tab is cut away with a razor knife after printing.

CAD

The OnShape 3D CAD files for this are here :

https://cad.onshape.com/documents/cfdfa65b9124359d31917769/w/5d50d6e327a22a4dfd0c29b2/e/ef9f4cfff541887119326ac7