Snap fix for strap webbing (20mm and 25mm versions)

Applications

Strap webbings are very convenient for all kind of storage, holding, fixing and securing applications. The straps are cheap and easy to get (50m of 1 inch, 25mm, straps are around 15€ at Amazon). Snap-buckles are also very cheap and also available here on Printables for 3D printing. But if you need to adjust the length of the strap frequently, this snap fixes come very handy. 

Simply bring the free end of the strap through from the bottom, this way a pull on the strap will just close the lever even more. 

The achievable holding force is in the range of several Kilogram and depends a lot on the used straps. Somewhat better straps are 1.6mm thick and result in a very good hold. Straps of 1.4mm are still working ok, but don't hold so great.

If you need a very strong, adjustable strap webbing buckle, I strongly recommend the double D ring principle. For a very minimalistic, but still very convenient principle, go for the side-hook mechanism. You will find appropriate designs on my site:

https://www.printables.com/model/121235-double-d-ring-buckle
https://www.printables.com/model/415770-side-hook-for-20mm-strap-webbing

Printing

The parts are easy to print. Just place them on your print bed in the uploaded orientation. Print with 4 perimeters and 100% infill and you are fine. I strongly recommend PETG over PLA, as plugging in the lever into the frame requires a bit of flexibility and might break a PLA frame.

Assembly

Once you have the frame and the lever of one size printed, just set one pin on the lever into one hole on the frame. Then use a screwdriver to bend the other side of the frame slightly outwards and snap in the other pin of the lever.

There are two ways of attaching the fixed strap to the frame (the end that is not snapped fixed, but is always connected to the frame). 

Nylon strap webbing can be very easily glued with superglue (cyanoacrylate). Just fold the strap around the end bar of the frame and glue it to the incoming strap over a length of 5-10mm. This looks very clean and results in a very strong attachment, if you use a clamp for gluing and allow for enough time for the glue to dry. 

In case you need a clamp to hold the strap while the glue is drying, be my guest:

https://www.printables.com/model/84103-one-inch-clamp-25mm-opening

The other way is to use one of the strap tensioners for the back-folded part, which are available on my site already.

https://www.printables.com/model/121221-strap-tensioner-load-optimized

Disclaimer

As said, you will not achieve ultimate strength with this kind of snap fix. By design, the strap will start to slip before the frame or the lever breaks.