Oh god you got one of those Demo forks.. You gotta measure the length of a fork tube thats not broken, measure the size of the tube that you broke, like 2 inches 4 inches etc; then line it up in a vice or something and weld it. Then it's threadless and if you want it threaded, just take it to the Plumbing department in Home Depot, you can buy threading tools or they will do it for you sometimes with there pipe cutting machine.