DIY Threaded insert (Helicoil)

[kess]

Hi imohtep56
You are right there is no way to sync the threads and especially when the inner and outer thread has different pitch (M10x1.5mm /M12x1.75mm).
The thickness between threads it was very thin but I decided to give a try and see if can be done.
The closer shop it was 150 km away from my place and for only one threaded insert it was waste of time. I had used two bolts M12x1.75x35mm for one correct threaded inserts at about 17~18mm length from each one. We have sync (peak /valley) about every 17mm with a random distance from the start point of cutting.