Updated 3/26/2020. Added MPCNC parts. Added 2 inch wide model

Why design another drag chain?
Other models I found all had printing problems, poor design, limited features and/or high friction when bending. I designed this for my MPCNC and will likely use this on my Ender 3 and future coreXY I plan to build.

Features!
Zero friction! very important.
Fast Print optimized.
Wire retaining snap in clip option. It works really well and prints easily.
Every angle optimized for perfect printing on cheep printers.
Zip tie open Chain for more unique ways of securing wire
Bidirectional models available.

Dimension - 1 in. wide
25.4mm Outside width
15.2mm Inside width
16mm Height
30mm pitch.
Total length ~45.6mm

Dimension - 20mm wide
20mm Outside width
9.8mm Inside width
16mm Height
30mm pitch.
Total length ~45.6mm

Custom Width?
To resize these should be easy in fusion 360 from stl file. Import (Do not open directly, messes scaling up). Find hard to find convert to Brep button. Cut the model down the center line. Extrude the bridge to 50% desired width. Mirror!! Done.

Printing tips. I got great results and designed to these numbers.
0.25mm resolution. I only tested these numbers.
0.4mm or 0.8mm nozzle for chains. I tested on 0.8mm only.
0.4mm nozzle and 0.2mm resolution for top clip. Nothing bigger.
No support.
50mm/s

What to print?
I recommend printing the clip in or zip tie version. If you want a strong drag chain then go for the closed version assuming you can run the wire through it. The 25.4 wide is recommended as it's got a good space for wires to fit in. Or print a mix which is what I did.

Note:
I have not printed the 20mm models yet. Please comment, will fix if problems.

To Do list:

30mm wide model? let me know in comments.
More connector ends? I need idea's and will probably post more later.