DIY Threaded insert (Helicoil)

[Frank S]

I've done this many times. One word of advice is to use the highest grade of bolt you can buy.The threads will be cleaner and stronger for the repair.
I usually like to drill a couple of 1/16" or 1.5 mm holes in thread line of the insert and the part being retreaded then driving in a short piece of rod into the drilled holes this will lock the insert into the part. Another advantage of using these DIY inserts is you can make a much longer insert than even an extended length coil thread.
The solid wall DIY inserts will resemble Ez-lock inserts more than the heli coil brand Both have advantages and disadvantages
Advantage of the Heli coil style is the thread will be the same pitch both inside and out side.
advantage of a solid wall type insert is any outside pitch may be used. This helps when you need to repair a fine thread that has been stripped simply use a large enough coarse thread bolt that will have sufficient wall thickness to leave a solid wall in the insert after the inside thread is tapped.