Need to pull head to insert heli-coil or similar insert?

[29er]

Is it possible to repair a stripped head stud hole without removing the head? Thanks!

[tbirdtbird]

no

[29er]

Well I was hopin' but it's what I thought. So, what's the insert of choice? I read over on the other place about heli-coils and time-serts. I think this is a repair I don't want to screw up, so I'll give it to my machinist.

[tbirdtbird]

I do heli-coils all the time with no problems. You do have to get them straight. You need to work carefully and methodically. I have heard of TimeSerts but do not know what they are or if they are different. Might just be a name for a similar product by another company.
I am sure someone here knows for sure

[Mitch]

I use a bottoming tap instead of a pointy standard style so the threads get cut to the bottom of the hole.

[29er]

Thanks guys. Good tips. FWIW, here's a video

https://www.youtube.com/watch?v=-JggtIxTapU

[tbirdtbird]

I looked at the TimeSert vid. It would seem to be a competitor to HeliCoils; I did not see an advantage. In fact, there is one extra step.
The most important thing is to drill straight, and it did not look there was much effort put into that. Whichever system you would use, that is key.
To start with I would use the head as a drilling guide, but there is still some slop to the bit. I will write more up on this later. Would also like to see input from Geo Miller and others

[29er]

Thanks, I value your comments. I get it that the hole has to be straight. I don't have all the stuff for this repair, and while I could make a jig, I don't want to screw it up. Never having done this before. I'm thinking it's a job for a pro.

[Mitch]

Are you planning to pull the head yourself?

[BILL WILLIAMSON]

DON'T try shortcuts when doing a thread insert. Follow the instructions totally or you "may" be SORRY!
Bill W.

[29er]

Yeah, Bill I hear ya. My Dad had a saying: "It ain't a piano!" when over-doing some simple thing. But I think installing the heli-coil and getting it straight is kinda beyond my courage and what I have available in the shop to do it myself, without building a jig or buying a lot of stuff I'll probably not use again, so it's off to my friendly machinist to get this job done by a pro. So, this one "IS a piano".

Mitch: Yes, I've already pulled the head. Came off pretty easy with my home-made head-puller and fortunately all the studs screwed right out ao I'm replacing them, too.