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Helicoil sizes?
Posted: 04 Jun 2015, 17:35
by kit
Can you get Helicoil inserts in longer sizes than 12.5 mm I have a striped wheel bolt and don't really want to have to replace the both discs as they are not that old?
Was thinking maybe to fit studs on the front anyway in readiness for when I get around to putting the alloys on

Re: Helicoil sizes?
Posted: 04 Jun 2015, 17:55
by kevtherev
Have you tried to re-tap the hole and use new bolts?
I personally would not use a helecoil as I would not trust it with the amount of torque required to tighten the bolt.
Discs are cheap, and the easiest option
studs are screwed into the hole on the front, so you could drill out and re-tap next size up and get a stepped stud
Re: Helicoil sizes?
Posted: 04 Jun 2015, 18:35
by itchyfeet
Yes Helicoils are in Ds so a M14 1D is 14mm, you can get 1.5 and 2D etc
but as Kev says Not confindent on helicoils for wheel bolts
Re: Helicoil sizes?
Posted: 04 Jun 2015, 18:50
by silverbullet
From an engineering standpoint, a helicoil correctly installed will be stronger than the original tapped thread in the iron front disc.
It's to do with shear angles and helical load paths. The coils are made from high-tensile stainless steel, which is much tougher than the threads cut into the cast iron hub.
There is rarely any strength advantage in exceeding 2D of threads, unless frequent disassembly and retorqueing is anticipated.
Re: Helicoil sizes?
Posted: 04 Jun 2015, 19:14
by itchyfeet
silverbullet wrote:From an engineering standpoint, a helicoil correctly installed will be stronger than the original tapped thread in the iron front disc.
It's to do with shear angles and helical load paths. The coils are made from high-tensile stainless steel, which is much tougher than the threads cut into the cast iron hub.
There is rarely any strength advantage in exceeding 2D of threads, unless frequent disassembly and retorqueing is anticipated.
Got to get in in square though as you have pointed out in the past.
Re: Helicoil sizes?
Posted: 04 Jun 2015, 20:10
by kit
Don't suppose you know where I might get one locally Itchy?
Re: Helicoil sizes?
Posted: 04 Jun 2015, 20:24
by silverbullet
itchyfeet wrote:
Got to get in in square though as you have pointed out in the past.
Defo. Disc cleaned up and clamped down on a pillar drill table and use of a back centre at the very least.
Re: Helicoil sizes?
Posted: 04 Jun 2015, 20:50
by what2do
Jesus, you're kidding me?? Whatever happened to trusting your eyes and possibly those of a mate? A drill with a 120 mm bit can be kept true in all planes to a great degree of accuracy with a little care and attention. How do I know? Because there are times during a harvest when a combine, tractor, implement simply cannot be stripped and taken back to the workshop, instead, it's old fashioned skill and practice that gets the job done. And I'm talking about components far more critical than a wheel stud.
To the op, ring around a few garages to gauge weather or not you can find someone with experience that leaves you feeling confident enough to trust them. Perhaps, you're competent enough yourself - I've shown harvest students how to do this. Greatest respect to you SB but have you seen any helicoils, timeserts done badly, I'm only asking because you appear to give this task a 'Haynes 3 out of 5' difficulty rating, so to speak. Most garages will do them and I wouldn't trust them with my finger of fudge...
Re: Helicoil sizes?
Posted: 04 Jun 2015, 20:51
by itchyfeet
kit wrote:Don't suppose you know where I might get one locally Itchy?
Got the kit you can borrow, same as sump plug afaik M14x1.5
coils on ebay, pm sent
Re: Helicoil sizes?
Posted: 04 Jun 2015, 21:50
by silverbullet
I have a scrap crankcase at the works that has 2 such M10 Timeserts stuffed into it.
Must have been done in-situ by a blind fitter working in the dark., they are that far off-square (in two planes) and both out of position.
Its not hard to get it right with the correct approach, but I wouldnt advise anyone to "trust their eyes" if they have no experience.
Re: Helicoil sizes?
Posted: 05 Jun 2015, 05:12
by itchyfeet
For the sump plug I use a piece of tube about 3 inch long and a little bigger than the drill/tap, cut square in a lathe as a drill jig ( check it's square with an engineers square) , hold it against the surface and then easy to centre the drill and tap to the tube by eye. This tube is a perfect fit so once pushed in you don't need to hold it.

Re: Helicoil sizes?
Posted: 05 Jun 2015, 08:28
by what2do
itchyfeet wrote:For the sump plug I use a piece of tube about 3 inch long and a little bigger than the drill/tap, cut square in a lathe as a drill jig ( check it's square with an engineers square) , hold it against the surface and then easy to centre the drill and tap to the tube by eye. This tube is a perfect fit so once pushed in you don't need to hold it.

Who's van is that? You been contracting yourself out

Re: Helicoil sizes?
Posted: 05 Jun 2015, 08:31
by what2do
silverbullet wrote:I have a scrap crankcase at the works that has 2 such M10 Timeserts stuffed into it.
Must have been done in-situ by a blind fitter working in the dark., they are that far off-square (in two planes) and both out of position.
Its not hard to get it right with the correct approach, but I wouldnt advise anyone to "trust their eyes" if they have no experience.
Well there's the thing, not matter how simple a job, it can always be done badly by the incompetent. The shocking thing is, why the "frell" is someone 'blind and working in the dark' even meddling with crank cases? And did they charge some poor, unsuspecting van owner a lot of money for doing the job? No wonder so many scare stories crop up on a regular basis.
Ps. That crank case isn't a recon from Elite or TES by any chance

Re: Helicoil sizes?
Posted: 05 Jun 2015, 09:48
by itchyfeet
what2d wrote:itchyfeet wrote:For the sump plug I use a piece of tube about 3 inch long and a little bigger than the drill/tap, cut square in a lathe as a drill jig ( check it's square with an engineers square) , hold it against the surface and then easy to centre the drill and tap to the tube by eye. This tube is a perfect fit so once pushed in you don't need to hold it.
Who's van is that? You been contracting yourself out

Tonydata on here (no he's not called Tony)
emergency repair during an oil change, earned a box of Doombar out of that
Be warned some helicoils the tang won't snap off, this one wouldn't, probably cheapo brand bought off ebay, worth checking one before fitting.
Re: Helicoil sizes?
Posted: 06 Jun 2015, 13:08
by kit
Good point about the torque on wheel nuts that is why the tyre fitter striped it in the first place.