Since a long time I had this idea spinning inside my head do make my own bag for my Kendo-gear (Bogu bag). As I already had a sleeve for my shinais (bamboo swords) made of my favorite sewing material, the woolen swiss army blanket, it was clear, that the bag had to be from the same material. I had even some sketches made some years ago, but as I had to take a break from performing kendo for almost six years due to my job, there was no need. But about 2 years ago I started again at a new club, so there was enough motivation to start this project.

Tools needed:

sewing machine
chalk
needles
scissors
knive
drill
pliers
rulers
steam iron
paper

Materials:

woolen blanket from the swiss army
swiss army tent canvas
zippers
some belts (guess what, also swiss army)
trolley bag

Step 1: Sketching

First I did some sketches, to get the design right. Took some measures to get the proper size to fit in all my stuff. It got a bit oversized in the end, but if I go on a training camp I will need the extra space for additional clothing and towels.

Step 2: Donor Bag

I had a trolley bag laying around at home which didn't use it very much, because it was very unstable. The distance between the wheels was to narrow, so it always tipped over.
I took it apart, to get at the wheels and handle, and disassembling it gave me also the basic ideas on how to build my own bag, as in which part comes first and how to build the bottom layer and how to hide the handle, when not in use.

Step 3: Building the Base

For the base I took a sheet of "PVC-Hartschaum" (hard foam?). It's very light and strong, but easy to cut with a knive and when you carefully apply heat you can bend it into round shapes.
First I laid out the parts, scavenged from the donor bag. This together with my gear gave me the proper size. Then I cut the PVC down to size and bent one end around some paper tube with the proper diameter. Better put some baking paper between iron and PVC if you plan to continue using the iron... ;-)
Then I drilled the holes needed and sticked it all together for testing. After all fitted together, I rounded the corners a bit, took it apart an put it aside for later.

Step 4: Creating a Pattern and Sewing a Prototype

Based on the measures of the baseplate I made my pattern/templates.

The bottom is made out of two layers of tent canvas. The outer layer is made of one part with the opening for the handle (front), one part that covers the baseplate and a third part that that forms the back and serves as a buffer if the measuring is wrong ;-). The inner layer is made of one piece, witch contains a zipper in the center to insert the backplate and fix the wheels and handle later.

The top is one piece with two zippers (woolen blanket).

The sides are three layers, the outer will be made of the woolen blanket, the inner of tent canvas (also military supply) and on the inner layer I will apply a third layer for pockets in the lower half.

To check the size and measurements, I sewed a prototype with some cheap fabric.

Step 5: Transferring the Templates and Cutting the Parts

As I was happy with the prototype, it was time for the real deal...

First I ironed out most of the kinks and folds on the tent canvas. Then I laid out all the templates on the canvas and blanket and transferred the shapes onto the fabric with some chalk.

Then I had to cut out all the parts.

Step 6: Piecing It Together, Part 1

In a first step, I sewed together the two side parts. It was a bit tricky with all the internal and external (hidden) pockets. You will have to look at the final product for some of the pictures to make sense.

Then I pieced together the "ring" which is the loop, created by bottom and top.

Step 7: Piecing It Together, Part 2

The next step was, to fit the sides to the loop/ring.

First I trimmed the uneven edges of the side parts down to about 1 cm.

For sewing it together, I aligned the bottom according to the marks from the templates and my experience from the prototype. Once aligned I stuck it together with needles to avoid slippage while sewing. I strongly recommend this especially in this part!

In the rush for the finish line, I totally forgot to take pictures here, but I think you'll get it anyway.

Once everything was sewed together, I put the baseplate in, made the cutouts for the wheels and screwed everything together. Thanks to putting together a prototyp first, I didn't have to improvise and everything came together smoothly!

So lesson learned in this: Make a plan, make a prototype, if necessary change plan, then stick to it!

Step 8: Show Off

Now the bag is done. It works as planned and makes hauling the gear a lot easier. And of course when on a tournament or training camp, this bag sticks out inbetween all the others black faux leather bags!