Step 7: Making the Springs
Next we'll make the nylon string springs.
Cut your 24ft of para-cord into 12ft lengths.
To form the springs, you will wrap the strands of para-cord around a jig like the one shown in Picture 1 . Using any scrap board (or your workbench), nail 2 finish nails exactly 7 inches apart. Removing the nail heads will make it easier to slide the string off after wrapping.
I recommend doing the next steps with one length of para-cord at a time to keep the strands from falling apart. Remove outer casing from your para-cord. Save this for the next step. My cord had 4 strands inside, yours may be different. If there are more than 4 strands, you will have to shorten the length or the completed spring will not fit in the frame. You will have to experiment a bit to find the best fit. Be sure to keep your strands together during the next steps.
Holding all strands together, wrap the length around the jig as many full rotations as you can. You will have a few inches left over after the last full rotation. Cut off this extra. Use one strand as your threading string. See Pictures 2 & 3. Loop the threading string through all layers of string at one nail and tie securely. This will ensure your spring strands stay together and will make threading the spring through the holes in the frame much simpler.
It's also a great way to keep the strings separated so you can get the spring tighteners and arms into place.
Repeat for the other 12ft length of para-cord.
Using the threading strings, hang your springs somewhere out of the way where the strands will not tangle. We will add the tighteners, springs, and bow limbs in the next step.