Introduction: Rucksack/backpack Repair: Replacing a Strap Adjuster

About: I'm a Computer Science undergraduate at the University of Southampton, UK, as well as an all-round computing, Linux and electronics enthusiast.
When I was getting off a Eurostar in Brussels this summer on Scout camp, a strap on my heavy rucksack caught on something, and the strap adjuster snapped. Thinking only of the train leaving for Rotterdam quarter of an hour later on the other side of the station, I put the adjuster in my pocket and forgot about it until I had come back home and seen replacement adjusters in John Lewis.

So, in this instructable I'll show you how to fix on one of these replacement strap adjusters. You can buy other replacement plastic parts as well, so you may be able to replace other parts with this technique.

Step 1: Tools and Materials

Tools
- Scissors
- Needle

Materials
- Strap adjuster. I found mine in John Lewis' Haberdashery section. Measure the width of the strap before you buy.
- Strong thread. I used button thread for this.
- Normal thread. This is just for the stitching that prevents fraying, so it should be thinner.

Step 2: The Way We Won't Do It

The first method I thought about was unpicking the existing stitching holding the webbing, putting the adjuster on, and stitching it all back up. But then I looked at what the stitching went through...

First, it goes through the back of the rucksack, followed by both parts of the webbing, the top flap of the rucksack, the cover for the main compartment, and finally a hem inside. That's six layers!

I didn't fancy unpicking and resewing all of that, so I decided to cut the webbing, put the adjuster on, and sew the webbing back together.

Step 3: Cut the Webbing

First, we need to cut the webbing. You need to cut it so that there is enough room to sew one side back on top of the other (a good 8 mm). Looking forward at the following steps should help you judge this.

Also, to prevent fraying, you need to cut between the humps of the webbing, which you can see more easily in the second picture.

Step 4: Prevent Fraying

Next, we need to prevent then ends of the webbing from fraying. I did this by threading the needle with the normal thread and tying the ends together, making a double thread. Knot the end again to stop it from pulling through the webbing, and then push the needle through the webbing from the under side, about two humps from the end. Keep doing this along the end of the webbing and cast off by tying a knot.

Step 5: Attach the Adjuster

Thread the webbing through the clip, using the end that isn't rounded and doesn't have a grip.

Step 6: Sew Back Together

Now, thread the strong thread into the needle and knot the end. You need to sew in a zigzag pattern, e.g. by having the first hole a couple of ridges away from the second, etc.

I could go through all three layers in this situation. Make it as strong as you can before casting off.

Step 7: Finished!

All you need to do now is put the other strap into the gripping side of the adjuster, and the repair is complete!