I wanted two 10' long leashes and decided to make them myself.
Step 1: Get Your Supplies, You Will Need; Hollow Braid Rope, a Fid (big Hollow Sewing Needle for Rope) and a Clasp
I bought 50 feet of hollow braid rope for about $8.00 US. The rope came with a fid and I reused a clasp from an old leash. It took about an hour to make both leases; It would have been faster but the dogs know a leash when they see one, even if it is not assembled, and did not understand why it took me so long to get it to work.
Step 2: Decide How Long You Want the Leash to Be and Cut the Rope to Lenght
Decide how long you want the leash, mark that spot on the rope and, to prevent the rope from unraveling after it is cut, wrap masking around the rope then cut through the middle of the tape.
Step 3: Make a Loop
You are going to make two loops: One a loop large enough to use as a hand hold the other a tighter loop to hold the clasp that connects to your pet's collar.
The fid and rope are going to be inserted into the hollow center of the rope to make both loops but in slightly different ways.
To make the larger loop; insert the rope into the open end of the fid then insert the pointed end of the fid into the rope far enough above the fid to make a comfortable hand hold (about 12 inches). Just before the fid is completely in the hollow center of the rope push the pointed end back out of the rope. Pull the fid out while holding the rope so the part inside the hollow center it stays there.
Step 4: Make a Loop 2
To make the smaller loop for the clasp; insert the clasp onto the rope, measure the fid, add about 1-2 inches and that is how far up the rope the fid should be inserted. Without inserting the rope into the open end of the fid insert the fid into the rope. Just before the fid is fully inserted push the pointed end of the fid out of the rope, insert the rope into the fid, then pull the fid out holding the rope so it stays in the hollow center of the rope.
Step 5: Tighten the Grip of the Rope
Once you have both ends complete you will want to make sure the end won't pull apart. The hollow center of the rope acts like the finger handcuffs you may have played with as a child; the harder you pull the tighter it gets. you will want to pull the section of the rope where it is inside itself to make sure it has a good grip and won't slip.