Methods for manufacturing modular leashes are disclosed. The modular leashes may comprise a flexible portion including a lead end and a handle portion. Manufacturing the flexible portion may comprise heating a pin and securing the pin to a lead end, so as to melt the lead to the pin using ambient heat from the pin. In some embodiments, heating the pin uses induction heating. Manufacturing the flexible portion may further comprise inserting the lead end into a sleeve, and securing the lead to the sleeve by crimping the sleeve onto the lead. Manufacturing the handle portion may comprise inserting handle ends into a first end of a sleeve and inserting a fastener into the handle ends. Manufacturing the handle portion may further comprise inserting a fitting into a second end of the sleeve so that a space between the sleeve and the fitting may receive the handle ends.