The saddle stitching technique—also known as hand stitching or two-needle stitching—is time-consuming but ends up stronger than a machine stitch. If a thread is cut on one side of a saddle stitch, but the other side remains intact, the overall stitch will continue to retain its integrity. Whereas in a machine stitch, if one side of a stitch is broken the entire length of the stitch will be compromised and eventually separate. While saddle stitching is more time-consuming many find it to be enjoyable—and even quite calming—once mastered.
For this skill we will be referencing the steps in the book, "Lacing & Stitching," plus using the following tools:
Step 1: Use the TandyPro® Stitching Groover to cut a channel into the leather so your stitches will be flush to the surface of the project. This step is optional but recommended for surfaces that will be exposed to friction that might damage threads over time. Alternately, you can use a wing divider to mark the placement of your stitch line without grooving a channel for the thread.
Step 2: Use your TandyPro® Pricking Iron to mark where your stitches will land and cut into the first layer of leather. Place the pricking iron prongs in the groove and hit the top of the iron with your mallet. The purpose of a pricking iron is to mark where your stitch will be and to cut through the surface of the leather—NOT to penetrate all the way through. You will use an awl to finish puncturing the hole later on or as you stitch. Aligning the tines of the pricking iron within the groove is very important to create a straight stitch. Pro Tip: Align one prong of the pricking iron with the last stitch mark to ensure that the distances between your stitches are always consistently spaced.
Step 3: Measure your thread out about five times longer than the segment you want to stitch. The amount needed may change based on how thick your project. It may seem like a lot, but it is better to have thread left over at the end than to run out and have to start over.
Step 4: Attach each end of the thread to one of the needles. With hemp or linen thread you will want to loop back the thread a few times to make sure it doesn't slip off the needle. With woven poly thread one loop is typically sufficient as the weave keeps the needle in place.
Step 5: Clamp your project into a stitching pony with the angle of the stitch marks pointing up and away from you. Left side: \ \ \ Right side: / / /
Your stitch will start with the mark furthest away and you will stitch down the row toward yourself. Make your first stitch hole by pushing your awl blade through the first pricking iron mark. Make sure the awl blade is aligned with the angle of the prong mark so that your stitches are at a consistent angle. You can then start the first stitch by running the thread through the hole and pulling the thread tight so the needles match up and the thread is equal lengths on each side of the stitch.
Step 6: Continue to punch the holes with your awl in your right hand alternating between using the awl and the needle as needed. Insert the needle from the left as you pull the awl out from the right. Pull the thread through the hole with some tension so the thread pulls toward the bottom of the stitch. With your right hand push the needle into the top of the hole careful not to catch the other thread. While the needle is still in the hole loop the thread on the left from the bottom over the needle. This 'loop' or 'cast' will lock the thread into place and give the stitch a consistent zigzag appearance on either side of the project. Lastly, pull the thread tight on both sides and repeat until you get to the end of your stitch line
Step 7: Backstitches prevent a stitch line from coming unwoven at the ends and can strengthen areas of stress in a project. To add backstitches use the same process from Step 6, only stitching away from you, re-stitching the same holes that you've already done. With a backstitch, it's important to add your new stitches underneath the existing ones and not to loop or cast the thread as you stitch. Usually, two or three backstitches are sufficient to keep the thread from coming out at the end.
Step 8: If you're using poly thread you can trim it off about 1/8" (1 mm) from the project then use a lighter to melt the thread so that it cannot be pulled back through the stitch. Be careful not to burn your project! If you're using linen or hemp thread a drop of glue tapped in with a needle provides the same locking function.
Step 9: To give your stitch a final polish, use a smooth-faced hammer or maul to tap and compress the stitches into the leather. This brings out the zigzag pattern and can reduce the friction wear on the thread over time.
Practice makes perfect! Similar to many other leathercraft skills, this may take time to master and might not be perfect on the first try. Keep practicing and the saddle stitch process will quickly become second nature!