Lincoln Service Parts 2 › Lincoln Electric 9SS31643-2 NYLON LOCKNUT, 3/4" NPT S31643-2 Lincoln Electric 9SS31643-2 NYLON LOCKNUT, 3/4" NPT S31643-2 Sale Price: $1.91 Original Price: $2.20 NYLON LOCKNUT, 3/4" NPT PURCHASE PRICE SHOWN IS FOR A QUANTITY OF 1 Add To Cart Added! NYLON LOCKNUT, 3/4" NPT PURCHASE PRICE SHOWN IS FOR A QUANTITY OF 1