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Hi Tom, I'll give you my own thoughts. The best and most permanent repair method is the use of a threaded insert as deadeye and Red Raider have suggested. I personally prefer the Helicoil though. The biggest problem you will have in using any type of insert in that size is in preparing the hole for it. I am assuming you will not be removing the parts to a machine shop and need to do all the work in place. A 3/4" standard bolt size will require drilling out to a larger size and retapping in order to install any type of insert. The larger size depends on what type of insert but it will be significantly bigger. If all you have to work with is a hand-held 1/2" drill, I do not think that the insert is a practical way to proceed, at least on your own. I certainly would not want to attempt drilling a 7/8" or larger hole in steel with a hand-held drill, especially in an arkward position...probably on your back drilling horizontally. It can get quite costly too, with special drills and taps that you may not have, especially in that relatively large size. That said, you may be better off with the Loctite repair kit you mentioned. I like Loctite products but have never used their thread repair kits. It all depends on the stress direction that your bolts see. The strength of the Loctite repair is far less than a regular steel thread. See this pdf file for a list of maximum bolt torques with this type of repair. As indicated, the max torque for the 3/4" bolt size is about 50 lb-ft. This is far less than the "normal" torque of 300 lb-ft for a standard grade 5 bolt. If your bolts take the applied load in shear, you may work out OK if you do not try to overtighten them beyond the 50 lb-ft. If your bolts are in significant tension that would call for a strong pullout resistance, that type of repair could be problematical. In any event, it would seem to be a relatively inexpensive fix and is worth a try, IMO.  Rod
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