Stud Removal by Electric Arc Welding
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ASTUD which breaks off flush or, perhaps, below the surface of a casting, is not the easiest thing to remove quickly and without damaging the thread in the component.
One way, of course, is to drill down the broken stud with successive sizes of drills until only a shell remains, this being broken away with a suitable tool. This method takes time, and there is
no guarantee that the hole will not have to be re-tapped.
An expeditious method of broken stud removal is by the use of electricarc welding, and an accompanying illustration shows a variety af broken studs removed by this method.
The method of operation, says the Lincoln Electric Co., Ltd., of Welwyn Garden City, Herts, is to lay a nut, having a slightly larger inside diameter than the stud to be removed, above the broken stud. The latter is then built up with weld metal, using the electric arc, so that the nut becomes welded to the top of the broken stud.
The electrodes used in the examples Illustrated were Fleetweld, manufactured by the Lincoln Electric Co., Ltd.
In some cases it is necessary to heat the area _surrounding a
" frozen " stud. This will cause expansion, and the stud can then be removed. In many cases, the welding operation will heat the area sufficiently to . permit removal, which is carried out by using a spanner on the nut as is done with an Ordinary bolt,