try TUNERS SUPPLY CO.,88 - 94 Wheatland Street,Somerville,Mass.02145.They sell several guages of music wire(piano,harpscord,zither) and brass harpsicord wire.They offer the wire in 1/4 pound coils.They also sell hitch pins,and zither tuning pins,tuning wrenches, and maybe other material that would be of use in hammer dulcimer construction. If you wanted smaller quantities than the 1/4 lb., you might try a piano/harpsicord tuner/repairman.In their catalogue description for the harpsicord/zither wire, they specify for dulcimers to use size 7 and 9 ( .018 and .022 ).