11-20-2019, 09:03 AM
(This post was last modified: 11-20-2019, 09:19 AM by doug tenney.)
I agree with Paul F on the Keenserts (brand name for key-locking inserts). I've purchased them from McMaster-Carr.
Unlike a Helicoil, they do NOT require a special tap. To keep them from unscrewing, they have two or more (depending on the size) longitudinal "keys" that are tapped into place as the last step.
My success rate using Helicoils for field repairs has not been as good. I'm guessing that hole has to be drilled perfectly straight, which obviously doesn't always happen in the field.
BTW, for spark plug thread repair on modern cars, I hear only good things about TIMESERTS. Like a Helicoil, they require a special drill, special tap and installation tool. In addition, they require a special counterboring tool to prepare the hole. In exchange, they have much thinner walls than Keensert. This is a pretty good video as long as you speed it up: https://www.youtube.com/watch?v=A4sS3T6g...tion=share
Unlike a Helicoil, they do NOT require a special tap. To keep them from unscrewing, they have two or more (depending on the size) longitudinal "keys" that are tapped into place as the last step.
My success rate using Helicoils for field repairs has not been as good. I'm guessing that hole has to be drilled perfectly straight, which obviously doesn't always happen in the field.
BTW, for spark plug thread repair on modern cars, I hear only good things about TIMESERTS. Like a Helicoil, they require a special drill, special tap and installation tool. In addition, they require a special counterboring tool to prepare the hole. In exchange, they have much thinner walls than Keensert. This is a pretty good video as long as you speed it up: https://www.youtube.com/watch?v=A4sS3T6g...tion=share