Repurposing an old shirt into a new tank or tunic lets you save money, avoid waste and exercise your creativity. Depending on the fabric of the original shirt, you might not have to do anything to the raw edges to stop them from unraveling. In fact, T-shirts, felted knits and fleeces don't need any finishing at all. However, dress shirts, standard knits, silks and other materials will fray if you don't hem them. Hemming can be cumbersome and time-consuming, but it requires only basic sewing skills.
Turn the shirt inside out, and lay it flat on a work surface. Measure the length from the shoulder seam to the place you plan to cut the sleeves, and mark your cuts in tailor's chalk. Cut the sleeves along your markings.
Fold the edges of the sleeves up 1.25 inches. Pin the fold in place, and iron the folded edge lightly to create a crease. Check the edge to make sure it is even all the way around. If it isn't, adjust it and press it again.
Remove the pins, and unfold the fabric. Measure and trim the edge so it is exactly 1.25 inches from the crease all the way around.
Fold up the bottom 1/4 inch of the sleeve and pin it. Press it lightly to create a crease. Remove the pins.
Refold the hem along the first crease and pin it. You should now have a hem 1 inch deep with a 1/4-inch fold turned under inside it, protecting the raw edge. Machine sew or hand stitch the hem through the 1/4-inch edge, so you are securing all three layers of fabric.
Take the pins out, and press the hem one more time. Turn the shirt right-side out.
Fabrics that fray only slightly might not require the extra 1/4-inch fold to protect the edge. For firm knits that are unlikely to unravel, simply fold the edge 1 inch and skip the additional fold.
Uneven hems make a shirt look messy and poorly made. Measure carefully and hem slowly, to produce a professional-looking sleeve.