removing a wonky helicoil

[BrokenBiker]

just had an ali head from a fiesta brought to me with the hope of me fixing a stripped hole. what they didn't say was that they had already tried repairing it with a helicoil but appear to have sent the tap in cock-eyed and ballsed it up. cant get a bolt to start in there, it just wants to lean to the point where it clashed with the side of the hole and wont go any more.

so, can a helicoil be removed, or am I drilling it out, tapping to m8 and telling them they have to drill the matching hole on what ever bolts to it?

 

[Spark plug]

You won't be able to drill it as its too hard, they come out easily, just use a scribe or similar to hook out the end of the helicoil the pull it out with some long noise pliers.

 

[BrokenBiker]

You won't be able to drill it as its too hard, they come out easily, just use a scribe or similar to hook out the end of the helicoil the pull it out with some long noise pliers.

was worried about hardness. will do as you say and pull it out then. will still have to drill and tap m8 by the looks of it, the hole doesn't look round and looking from underneath only one half of it has thread cut onto it. really does annoy me when people have a half arsed go and then make life harder for people that could've done it properly the first time

 

[awemawson]

Can you not make a threaded bush? Drill out and tap to a diameter that gives you enough meat to drill and tap the correct internal thread, then screw the bush in with Loctite.

 

[doubleboost]

was worried about hardness. will do as you say and pull it out then. will still have to drill and tap m8 by the looks of it, the hole doesn't look round and looking from underneath only one half of it has thread cut onto it. really does annoy me when people have a half arsed go and then make life harder for people that could've done it properly the first time

I get loads of this type of work

 

[normspanners]

just use a time-sert or if hole is very damaged a big-sert http://www.wurth.co.uk/hand-tools/thread-repair-and-reinforcement/thread-repair-system-time-sert
with them they use the next size up thread with the size you want taped in centre but if struggling you can put one inside the other ie go up two sizes.

 

[BrokenBiker]

well, job is done, had a look through my box of crap that might be useful and found a few inserts I made ages ago, m8 on outside and m6 on inside so used that and a bit of epoxy resin for good measure

 

[premmington]

I hate helicoils with a passion!

I don't think I have used one since I discovered thread inserts (timeserts)

http://www.timesert.com/






.

 

[doubleboost]

I hate helicoils with a passion!

I don't think I have used one since I discovered thread inserts (timeserts)

http://www.timesert.com/






.

Helicoils have there place

 

[Spark plug]

I hate helicoils with a passion!

I don't think I have used one since I discovered thread inserts (timeserts)

http://www.timesert.com/






.

Helicoils are fine once you get the hang of them. I sat for days on end installing thousands of them in aluminium casting as an apprentice.

 

[Pete.]

I had to helicoil most of the M6 engine-cover threads on a CB650 once, after we bought an engine for my dad's bike. The bike it came out of had been on fire and then left standing. For some reason it caused all the threads to come out with the bolts. We only needed the cams at first so it didn't matter but later it threw a leg out of bed and we had to re-build it with the salvaged cases. The helicoils worked just fine.

 

[PhillipM]

Helicoils have there place

Yep, they have advantages over a solid insert if they're correctly installed.

 

[daleyd]

I hate helicoils with a passion!

I don't think I have used one since I discovered thread inserts (timeserts)

http://www.timesert.com/






.

I've had a few disasters with helicoils over the years, never seen those though - they look good!

 

[Windy Miller]

Yep, they have advantages over a solid insert if they're correctly installed.

What are the pros and cons of a helicoil over a solid insert?

 

[Spark plug]

What are the pros and cons of a helicoil over a solid insert?

A solid insert would need a bigger hole drilling and tapping, eg. An m8 hole to repair an m6. Ware as a helicoil will only be marginally bigger.

On the down side tho to fit a helicaoil you need special tools and for each and every different size hole the tools are also different sizes.

 

[BrokenBiker]

A solid insert would need a bigger hole drilling and tapping, eg. An m8 hole to repair an m6. Ware as a helicoil will only be marginally bigger.

On the down side tho to fit a helicaoil you need special tools and for each and every different size hole the tools are also different sizes.

the m6 helicoil uses a 6.3mm drill, so you need pretty much no extra space around the hole. I was fortunate with the head that I could fit an m8 in there without coming anywhere near the edge of anything. first job for when I get another lathe is make a job lot of inserts

another pro for helicoil is, as I found, they are very easy to pull out, where-as the insert I used yesterday would be a nightmare to get out as I stuck it in with epoxy resin. but it is only mild steel so could easily be drilled

 

[premmington]

If you can go up to the next thread size. I do think this is the best solution. But sometimes this is not possible, there is just not a enuf room to enact this!

Snapped bolts in turbos is a big problem to us! I have tried most solutions!

A local engine builder near to us! Uses one method I have not tried. He over sizes the hole, then fills the hole with TIG braze, then drills on re-taps the softer metal!

I have used this method with alloy castings, where they have stripped the alloy thread.



.

 

[premmington]

What are the pros and cons of a helicoil over a solid insert?

Helicoil kits are expensive.

Timesert kits from Wurth are expensive.

(Oh... Anything from Wurth is expensive)

Going the next thread size up and using a bigger bolt is cheap!

 

[BrokenBiker]

the common problem I have when repairing threads is that if I drill an m6 hole out to m8, it may not be possibly to drill out the hole on what ever clamps to the threaded hole. this is an issue on the megane inlet manifold as the holes int the manifold are sleeved, and aren't thick enough to take an 8.5mm drill, which then leaves nothing but soft plastic to clamp onto. hence why I use helicoils

 

[Spark plug]

Another option if you have little clearance to drill out the mating part is to drill and tap the next size up and fit a stepped stud and use a nut to secure the part.