Modular (Box) Chain System

A modular chain system with medium strength seemed like a good idea when I started it. But I am not sure what to do with it. So for now it is in the fun and curious category of things to print. I hope to one day find a purpose for it. I have designed a host of accessories that can snap on and off hoping one of the combinations will be useful. You can snap lengths of chain together to make a longer chain (of unlimited length). And, I think I will dream up some more accessories/attachments for it over time.

The chain links are 10mm long, 8mm high and 12mm wide so I am calling this the 101208 series for now. I may make a bigger stronger version at some point in the future. I started with a smaller version but it was quite weak so this design has been arrived at by balancing size with some meaningful strength. It seems to have a pull strength of about 16kg / 35 lbs when printed in PETG.

The idea is that any chain or accessory can be combined with any other chain or accessory creating a modular system that can be configured however you want and reconfigured endlessly.

The design revolves around a single common chain link and then a single male and female clasp side. With these, endless chains can be created and any conceivable accessory can be added.

When the male side of the clasp is inserted into the female side of the clasp, the hooks on the end of the male side catch into slots on the sides of the female clasp. These are dependent on the prongs of the male clasp flexing inward as the clasp is inserted and then flexing back out once it is fully inserted.

My original plan was that you could use your fingers to release the clasp but I found it was too small and as a result, I needed to create a key to release it. The key works is applied across the clasp and once fully seated presses the male side hooks inward and allows the clasp to be pulled apart.

So far I have made multiple lengths of chains including some smaller ones that make nice little keychains or bracelets. I have made the longer chains in lengths that will fit diagonally across various print bed sizes. Trying to cover as many possibilities as possible, I have also made male-to-male, female-to-female and male-to-female connectors.

I have designed a variety of loops and hooks so far. As well as a super small ring is intended for use wth a steel key ring.

I definitely have ideas for a few more accessories which I will add when I have time. And, I invite anyone else to make accessories and post them too. I have posted the STEP files for the link, as well as the male and female sides of the clasp.

One potentially major issue is that I have not printed these in PLA yet and I am concerned the male side of the clasp will not have enough flexibility when printed in PLA. If you print it in PLA please let me know how it comes out. If needed I can post an alternative design that will be more forgiving for PLA.


I have tried to make my main print settings visible on the Cura screenshot but in case they are difficult to read I have summarized them again here…

Material: I choose to use PETG for its durability and flexibility. See my note above regarding PLA.

My Setup:
Nozzle = 0.4mm

My Settings:
Layer height = 0.2mm
Line width = 0.45mm
Wall count = 4 (1.6mm)
Infill = 40%

Designed to print without support being added. I have designed in support for the male side of the clasp as shown below.

Print Orientation: As shown in the screenshot(s).

Where to Get My STL Files

You can find my posted STL files on the following sites:





Licensing, Comments and Feedback

I am happy to share my designs (STL files) with our community and welcome you to print them for yourself and even gift them to others. However, I do not permit the use of my designs for commercial purposes (i.e. you can not sell my design(s) or products printed from my design(s)). Thank you for respecting this. If you wish to sell them please contact me and we can work something out.

If you print any of my designs I would appreciate any feedback. I am especially interested in how different designs print with different printers and materials. And, it is always nice to hear back from people who use my designs.

I am working towards commercializing some of my products and experimenting with a few different avenues. I am currently exploring the use of an ETSY shop, my branded site Buku Design and also on Amazon (Canada and USA, ). If you have time please visit my products there to help increase traffic and search success. Thank you.


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