I haven't used my sewing machine for probably 20 years, but my daughter is having her first baby and so I want to make some swaddling blankets. One of the blankets is a skull-and-crossbones theme (for girls) and I want the bias tape to be skull-and-crossbones, which can't be found in any store, although I suppose you could order it online somewhere. That leaves me with making my own bias tape, and the bias tape maker size I need also can't be found in any of the stores so I've been searching online for a DIY (and I don't want to pay for one). I found a tutorial that I'm improving upon for my needs.
My fabric will be 3 1/2" wide and the finished product will be 7/8" wide; however, I don't see any reason why you can't make your own jigs for the folds and widths you desire.
NOTE: This instructable does not show how to make the bias tape. It's simply the jigs I use to make the folds.
Cardboard (I used the thin stock from a FedEx overnight envelope)
Fabric (should be washed and ironed and made into pre-made bias tape)
A straight pin or two
Step 1: Making the Jigs
As you can see, the cut out slots all align on the left side. The reason for this is to keep the fabric straight for each fold. Obviously, the cuts aren't perfect, but the goal is to keep the fabric as straight as possible in order to achieve consistency in the folds.
Measurements shown are for the total width and length of each jig, the spaces between the slots, and the slots themselves. The reason for the 3/8" slot on the third jig is because the final fold will be thicker. All measurements can be adjusted for the fabric and size of bias tape you may make.
Step 2: The Fabric
The first image is of a piece of bias tape I used to work from to determine the width of the fabric I'll need and the width of each fold. It shows the finished product and also how it looks unfolded.
The second image is of the fabric I used for this Instructable.
Step 3: Jig 1: Weaving the Fabric
With the right side of fabric facing down and from the back of the jig, insert the fabric through the first slot.
Keeping the raw edge on the left side, fold over the right edge of the fabric to weave to the back of the second slot and then back to the front through the third slot, keeping the fabric lying flat. When it's through the third slot, make any adjustments and use the iron to press the small portion that is through and pin down to the ironing pad the fabric that was run through the slots. Now gently pull the jig away from the pinned down portion and continue pressing the fabric with the iron as you move the jig.
The third image above shows what it should look like.
Step 4: Jig 2: Weaving the Fabric
The first slot on the second jig is the same width as the slots 2 and 3 on the first jig.
Starting from the other end of your bias tape, right side of fabric facing down (the raw edge will now be on the right side and the first fold will be on the left), weave your fabric through the slots as shown in the previous step, adjusting the second fold to fit through the second and third slots.
Use the same procedure to press and pin and continuing pressing as you're moving the jig away from the pinned down portion until all of your bias tape is worked through the jig. The second image, although kind of tough to see, shows that you now have a fold on the left and the right sides of the fabric.
Step 5: Jig 3: Weaving the Fabric
The first slot on the third jig is the same size as the second and third slots on the second jig.
Starting from the other end of your bias tape, right side of fabric facing down, weave your fabric through the slots as shown in the Jig 1: Weaving the Fabric step, adjusting the third fold to fit through the second and third slots.
You'll notice that in making this last fold, one fold is wider than the other (which is correct) by about 1/16". Use the same procedure to press and pin and continuing pressing as you're moving the jig away from the pinned down portion until all of your bias tape is worked through the jig.
And there you go! You just folded bias tape from fabric. I hope these instructions were clear and easy to follow. Please let me know if I can expand on them. Now go make some bias tape in any print and size you want!