There are numerous thread repairs. The best fix is Helicoil, but there is a cheaper competitor. It is carried by Wholesale Tool. You should be able to find them online and find a nearby store. There is a short kit that has the special tap, the inserter tool, and about 10 thread repairs. You supply the proper drill bit. They resemble a spring with a internal vee and an outside one, there is a tang across the bottom. The inserter is screwed in and a drive dog engages the tang to drive it into the threaded hole. After the insert is installed a rod is inserted and the tang snapped off. It can be retrieved with a magnet on the rod or blown out with air. I put one in magnesium for a 1/4 X 20 setscrew. It is MUCH stronger than a magnesium thread. There is also one that has a thicker wall and a nylon insert to hold it in. They can be bought individually and the OD is a common thread. Helicoil is standard stock in most good auto parts stores but they are pricey. They are great for oil drain and sparkplug thread repairs. I once had a 1953 Sunbeam motorcycle. They had a tendancy to blow head gaskets as the alloy head would scallop between studs. I had it and the block planed and made a 1/16" solid copper headgasket and annealed until it was dead soft. I replaced the head studs with auto connecting rod studs in Helicoils. I tightened that sucker till you could almost see the copper ooze. Never another problem.
Keith (trackfodder) Williams
