Some people enjoy warping the loom even more than weaving. There are several steps involved, but each is logical and straightforward. This article describes back to front warping. The technique allows one person to warp the loom by him or herself. There are four main steps to warping a loom: winding on the warp yarn, threading the heddles, sleying the reed, and tying the warp yarn onto the front apron rod.
Wind the Warp Yarn onto the Back Beam
Attach the raddle to the back beam of your loom. Short bungee cords work great to temporarily affix it. Bring the back apron rod under and around the back beam, so it travels over the raddle. Remove the reed and push the heddles on each harness to the edges of the loom, so you have an open space in the center for your yarn to pass through. Hang your lease sticks from your loom's castle behind the harnesses, or secure them to the horizontal sides of the loom. Shoelaces or heavy yarn work well for this task.
Take the warp yarn to the front of the loom. Unchain 2 feet of yarn. Drape the majority of the warp chain over the front beam and send the unchained part, which includes the cross, through the harnesses toward the back beam. Find the two halves of the cross, and insert a lease stick through each half. Tie the ends of the two lease sticks together, so the sticks don't accidentally slip out of the yarn during the winding.
Slip your fingers between the two layers of yarn, delineated by the cross, closest to the back beam. Remove as many ties as necessary from the back apron rod; the number depends on the width of your warp. Insert the apron rod between the two yarn layers, spreading the warp bundles evenly across the width of the apron rod, using the raddle to hold them in place. Reattach the apron rod ties as necessary. Always center your warp on the apron rod.
Cut and remove any waste-yarn ties on your warp yarn; be careful not to cut your warp. Slide the lease sticks close to the harnesses. Go to the front of the loom and unwind another loop or two of yarn. Shake the yarn sharply several times to untangle it. Don't smooth the yarn unless you have no choice; the more you work with it, the harder it is to manage. Check that all warp threads are evenly taut and not caught on one another.
Move to the side of your loom where the loom handle is. Grasp the lease sticks in one hand, inserting a finger between them to allow the yarn to move smoothly. Begin winding the warp slowly, allowing the lease sticks to move toward the back beam. Stop winding when the lease sticks can go no further, or if you notice the yarn catching anywhere on them. Untangle the yarn at the lease sticks, if necessary. Walk behind the back beam and grasp the lease sticks, one hand on each side of the yarn. Slowly push the lease sticks toward the harnesses, wiggling them slightly as you go.
Return to the front of the loom. Unchain two more loops of yarn. Shake the yarn vigorously a few times. Check that all strands are evenly taut and remove any tangles. Return to the side of your loom and wind the next section of warp. Maintain an even tension on all warp threads as you wind to create a uniform fabric. Separate each layer of yarn on the beam with layers of paper or cardboard to create a smooth surface for the next yarn layer. Brown craft paper works well. You must divide each yarn layer to keep the threads from sticking together which would result in uneven tension.
Thread the Heddles, Sley the Reed, and Tie On the Warp
Read your pattern to calculate how many strands of yarn need to be threaded on each harness. Start at the right side of the loom with harness one. Count the number of heddles you calculated you need and move them to the center of the harness. Count and move the appropriate number of heddles to the center of each successive harness.
Return to the right side of the loom. Select the first strand of yarn and thread it through the heddle attached to the appropriate harness as instructed by your pattern. Take the next thread and pass it through the eye of the next heddle connected to the correct pattern harness. Continue threading in pattern until you reach the middle of the loom and run out of heddles. Loosely tie a loop in every "inch" of warp yarn as you go; the size of an "inch" depends on how many ends per inch (epi) your pattern calls for. Organize your yarn this way to prevent tangles and easily spot errors in threading. Thread the second (left) half of the loom in the same manner but without pre-counting the heddles.
Reattach the reed to your loom. Calculate how many threads are in one half of your warp. Divide that amount by the number of ends per inch (epi) in your pattern. For example, if your warp is 480 threads wide, half that number is 240. The pattern calls for 20 epi, so 240 divided by 20 equals 12. Half the width of your fabric is therefore 12 inches. Select a 10-dent reed, which means it has ten dents or openings per inch. Sley or thread two threads in every dent, since your pattern requires 20 ends per inch. Multiply the numbers of dents per inch (10) by the number of inches in the half width of your fabric (12): the result is 120.
Count from the center of the reed 120 dents to the right. Start sleying at this point by threading the two right-most warp threads through the first dent, then the next two through the second dent. Continue in this manner, moving left until you reach the center of the reed. Do do not count dents on the left side of the reed. Carry on sleying two warp threads per dent until the entire warp is threaded.
Bring the front apron rod under, around, and over the front beam. Engage the brake so the apron rod will not move. Tie the 1-inch bundles of warp yarn onto the apron rod, one at a time, starting in the middle and moving outward, alternately tying an inch to the left and to the right. Recheck the yarn tension in the middle when you finish tying all the warp bundles; the middle yarn often loosens during the tie-on process. Tighten those bundles, if necessary, to create an evenly tensioned warp. Start weaving.