Replacement cheese slicer wires are available from kitchenware retailers such as Sur La Table or Williams-Sonoma and from online sellers such as Amazon.com. To find a match for your cheese slicer model, measure the length of your old wire and note whether the fastener at the end of the wire is a ring or loop. Most wires range from 5 to 6.5 inches.
Search online first for replacement wires manufactured by the brand of cheese slicer you own, if you know it, since this helps ensure you match the correct wire with your model. Some manufacturers of high-end cheese slicers, such as Prodyne, provide free replacement wires if you send them the broken wire with a self-addressed, stamped envelope. A kitchenware store also may be able to order the replacement wire for you. Replacement wires are typically made from stainless steel and come in packs with multiple wires.
Install the new wire by unscrewing the handle or fastener screw and popping out the old wire, including any broken pieces. The next steps depend on the type of cheese slicer but usually require you to slide the end of the new wire with the loop or ring into a groove and slide one end of the handle through it. Pull the wire tautly, and replace the screw or handle. Note that the wire may break if you stretch it too tightly or over-tighten the handle.