Doodad Bolt Removal Tool

This is an inexpensive (~$50 total) tool for extracting old rusty anchor bolts. The idea is to place a stainless, larger bolt in the same hole rather than drilling another one. The main component of the tool is a ball screw and ball nut (https://en.wikipedia.org/wiki/Ball_sc.... It is somewhere near 90% efficient as opposed to the ~25% efficiency of ACME threads or a standard UNC threaded bolt. You will get much more pulling power in exchange for much less muscle, and it travels at about 8 turns per inch so the work pace is really quick. The ball screw was custom machined by 'RDB Bearing and Mechanical Parts' in China for about $26.00. Find them on aliexpress.com. The custom part is getting 1/2-20 UNC threads on the end of the tool so that it will fit a coupling nut to attach it to the bolt. More details at MountainProject.com in the bolts & anchors forum.