Now that you have the straps laid out, time to start sewing. I spaced my stitches 1-2 mm and used heavy duty upholstery thread. Just sew two straight lines down each side of the strap.
(A few notes on sewing. Use pins to hold the fabric together before you start sewing, its much easier. Invest in a good denim needle. You'll need one for this type of work. When you first start, be sure and run forward an inch, then back to the start so that your end doesn't come loose later. On my machine, I can hold a button in and the machine will go backwards. A ripper [to pull out stitches] is really helpful because no matter how hard you try, you will inadvertently sew one side of the bag to the other. Speaking of which, be sure the rest of the fabric doesn't get folded under while you're sewing, or you'll be using the ripper!)
Sew a box on the strap. If your machine will let you offset the needle to each side, this will help you stay close to the edge.
Alright, you've got all your straps sewed on. Next we need to do the corners. Mark a line 1/2 inch in all the way around the "T". Next, cut diagonally at each corner to your mark. Now, fold each edge, starting at the corner together so that the two inside edges are facing out. Pin it. What you are going to do is sew this, and then turn it rightside out later so that it looks good. It should look something like this:
Once you have finished all 4 corners it should look like this:
You'll notice three things if you look close. First I pined the strap tails so I wouldn't inadvertently sew them to something, second the corner has one side taller than the other. This is because we haven't hemmed it yet. Lastly, the bag is inside-out.
Next hem the un-hemmed edges so that they are the same height as the other piece. Be sure and fold the fabric the right way.
Now you're ready to do the rest of the corners. You'll need 4 6" pieces of 1 1/2 " webbing. Turn the bag rightside out, and pin the webbing so it overlaps each corner joint, and is even with the top of the bag.
Sew it on. You'll notice I boxed this and put an x in it. Its helpful to use both forward and backwards on the machine, and put the machine near the edge of the table so that the rest of the fabric has a place to hang while you sew. Let the machine do the work, all you need to do is guide it.
Now that the 6" strips are done, you need to add the top horizontal strip of 1-1/2 webbing. You can see above that I started near a corner, and worked my way around over the blue straps, and the corner straps. I also used a wide zigzag stitch to lap the ends together. (Don't sew the blue strap tails on accident. I did one this time around and had to undo it.) If your machine can't get through the areas with multiple layers of webbing, just come back and sew those by hand.
Almost done. Now we need to do the buckles. You'll need 4 4" pieces of 1" webbing. You are after something like this.
You want the bottom of the webbing to be 5" from the top, or so the cam buckle, when pulled tight will be just below the 1-1/2 webbing. Its helpful to first pin the webbing to hold it together, and then pin it to the dropbag. Again, sew an X. If this is too much for your machine, you may need to sew it by hand.
Once all the buckles are on, you just need to cut your blue strap tails at an angle and melt them so they feed through the buckles easily.
It took me about 4-5 hours, but I'm a little slow.
I got the fabric for free from Peterson Canvas in Fort Collins, but i would guess textiline is aroudn 10 dollars a yard, and you shouldn't need much more than 2 yards TextileneŽ PetTex PVC Coated Polyester Mesh - Black
Cam and straps I got from strapworks.com Best place I could find. I went a bit overboard and bought 50 buckles and 1000' of each webbing. I would suggest just getting the regular weight, not heavy duty unless you have a nicer sewing machine.
Overall, I bet I spent 30-40 dollars?