Here we have a 1 1/8″ threaded fork from a 1992 Specialized Stumpjumper. The idea was to extend the fork steerer so that a modern threadless system could be installed. 

The steerer was cut down and a long 1″ sleeve was inserted and welded in place. After a 1 1/8″ tube was placed over the sleeve and welded in place. 

We took the time also to install a disc brake mount on the fork to give this retro MTB some modernity. Click through the photo gallery to see the full process!