Antique treadle sewing machines are collectibles, and they can often be restored to working order with simple maintenance and repairs. One common problem with old treadle machines is a broken or worn belt. New replacement belts are available for vintage Singer and other brands of treadle machines. Choose a leather replacement belt, if possible. Cord-type belts and man-made materials may not perform as well as leather. Expect to pay £6 to £9 for a leather replacement belt.
Examine the belt's route around the machine if the original belt is still on the machine. The new belt will follow the same route, so look for guide hooks, loops and grooves and remember how the original belt was threaded through them. Get under the machine to see all areas around the treadle pulley and pedal. Use a utility knife or large scissors to cut the old belt and remove it.
Place the new belt over the hand wheel. Thread the ends down through the cabinet openings, which are holes near the base of the sewing machine. One opening will be in front of the machine base and one will be behind the base. The belt should run behind the bobbin winder, a small wheel that can be moved to contact the belt on the front of the machine. Both ends of the belt should be under the cabinet now.
Thread one end of the belt around the treadle pulley. You'll have to get under the machine to do this. The treadle pulley is the wheel attached to one side of the treadle. Thread the belt end through guide hooks; some models may have loops instead of hooks. Bring the ends of the belt together at the front underneath the machine.
Pull the belt ends snugly around the machine. One belt end will have a metal staple. A replacement belt is longer than necessary so you can custom fit it to any treadle sewing machine. Overlap the belt ends, and mark the point where they intersect with a pen. You can hold the ends together and rotate the belt a little to test if it is snug enough to operate the machine. Cut the non-staple end of the belt on the pen mark. Leave the staple end intact.
Make a hole in the cut end of the belt with the awl or nail. Open the staple with pliers, and join the two ends so they are flush. Tighten the staple with the pliers.
Leather belts may stretch slightly. If your new belt loosens after use, open the staple and shorten the belt by trimming the end slightly and repeating Steps 4 and 5.