Designing a 3d-printed clasp for a sports gear bag

Problem statement

Swiss kids have extensive hands-on lessons in primary school (called TTG¹), where they work on all kinds of handcraft projects – pottery, papercraft, sewing machine work², and more.

My son’s latest project is the ubiquitous sports bag that virtually all Swiss kids use for gym class – a canvas pouch that closes by pulling on the shoulder straps.

One fault I found in that design is that it slides off kids’ shoulders fairly easily.

So I set out to fix that – with a bit of 3D printing.

This is wholly deserving of the quickie tag – it was a quick job…

Solution

You know the whole:

1. Sketch
2. Extrude
3. Possibly fillet/chamfer

Fusion360 workflow?

Yeah. This was exactly that kind of job:

Sketch

Sketch the basic 2D shape

(with some model params)

Extrude

Extrude the basic shape

Fillet/chamfer

Fillet + chamfer (to cut sharp corners)

Extra credit: Personalization

As a stretch goal, I added some personalization (an engraved name):

Finished model

Here’s the final result (sans the personalization, since you probably don’t want that):

The stl file as well as the f3d design file can be yours for the little price of free, under CC – BY NC SA license³.

Printing

It took two tries to get the dimensions just right (I designed the whole thing based on a rough measurement of the lanyard diameter), but the result turned out pretty cool, no?

The bag Alan sewed professionally, with the quick-hack clip I cobbled together in Fusion 360. ;)

Closing words

I don’t know – silly things like this remind me how much I enjoy living in a century where going from an idea to a finished “product” takes just a few keystrokes and a 30-minute wait⁴.