I too have used this trick, (or a variant of it,) I used to have a lot to do with heavy machinery, where a lot of parts (bulldozer blades, digger buckets etc.) are pinned on with pins sometimes up to 3" thick.
Most times, when they break, it's at the hole through the pin where the lynch pin goes.
I used to lay a piece of copper or brass rod across the broken pin where the lynch pin would go and weld over it, then knock the rod out when I'd finished, leaving an accurately placed hole behind.
I'd then run a drill through just to check I hadn't inadvertantly left any lumps or bumps behind, although usually it was pretty clean.
If the rod didn't want to knock out; well 3" of copper or brass is easier to drill through than low hydrogen steel!
It takes a lot of patience to lay just weld after weld down, and waiting for it to cool, but if a replacement part is obsolete, or on the other side of the world, sometimes your options are limited.

johnboy