You can use a product called a "Helicoil", basically it is a stand-alone thread, it comes with a special size drill, tap and inserting tool . Drill and tap where old inserts are, then screw the "Helicoil" into the new thread(use loctite). When the "Helicoil bottoms out, it breaks for the insertion piece and hey presto.....a new thread. Can be brought from a good hardware store, or engineering products store. Come in most size threads, eg, M5, M6 etc
www.engineproblem.com.au/helicoil.htm http://www.nationaltoolwarehouse.com/xq/asp/prodid.14331/TID.{8A07620C-B221-4F5C-9835-FECF47D68E13}/qx/product.htm
For some reason the bottom link doesn't work....cut and paste whole link into browser
