Any other Heli-Coil junkies in here?

[turboglenn]

I was just digging through some bolts looking for info for another post here and came across my "heli-coil box". It's a little plastic storage tote with nothing but heli-coils, the tools & taps for installing them, the taps for the size hole they are repairing if i just want to make a new hole and thread it and the drill bits for all the above combos. I do mainly metric so i keep m6 x 1 ...M8 x 1.25 and M10 x 1.25 and of course i have a few standards 3/8 x 24 .. 7/16 x 18 and one other one.

When I build an aluminum block or head engine if the customer is up for it and knows what i do about aluminum and threads I'll do a complete block or head if they have the money for it (some do) and then i just feel like it's "built ford tough" LOL

Personally on my car i do as many as i can in spurts when i have something off or have a head machined or anything like that. aside from wishing i could find an easier way to bore the new hole straight, it is for some reasom, something i absolutely love to do...kinda weird i gues but oh well

So anyone else nuts over heli-coils ?????

[FusionKing]

I cannot even imagine it. I would spend my hard earned money on studs LONG before I wasted my time cutting out sevicable threads only to install repair threads right back into aluminum, only bigger.

Once you have installed a heli-coil and it strips you have a real problem.

As far as doing all of an entire assembly by hand after it was done by a precision mill?? Even if you was to do this with a bare block in a big mill it would need to be designed into an assembly because you are cutting so much meat out of an aluminum part only to still impart a twisting force on it.
Studs eliminate twisting force and have to be pulled out vs stripping.

IMO user installed heli-coils are a method to simply "get by" when something goes bad wrong. Factory installed steel thread inserts are application specific and are the correct length for the bolt and installed during production. It just is not the same.

If I was gonna do something THAT crazy I would drill/thread the block out to accept bigger STUDS and then drill out the heads to accept them.
Just my opinion tho...YMMV

[PJinNJ]

HC's are used by me only when I have no other choice at the moment. I usally remove them and effect a proper repair when I can.

[Conrad_Turbo]

I hate threaded inserts (Helicoil is a brand...like Kleenex), I only use them when the hole is stripped or cross threaded, otherwise they're never used. I couldn't imagine drilling out a perfectly good hole to put a threaded insert in.

[turboglenn]

****, I guess i'm the only one then :P I won't even put a exhaust mani on a turbo car untill the threads have been heli-coiled unless it's a new casting (your "perfectly good hole" then i wouldn't either). But from the years i worked on road race cars (porsche club 944's 928's 911's etc.. ) The rules of the shop i worked in were that we wouldn't assemble a used block without thembeing used on all the exhaust mani and block bolts for the brackets, turbo supports, cooler lines and cooler housings on the block. Half the time the holes in the block after some 5-8 even 10 years of service are so worn out in the threads that you can't even torque half the accessories to spec. before they strip out. Maybe it's just that the cars i've done them on lead very hard lives, running maxed out about 95% of the time and being stripped, inspected and repaired/re-assembled every season

I've never had a heli-coil strip (and yes i know it's only a brand name) but then again i always torque things correctly and use anti sieze on everything aluminum.

[Sberry]

I can see good use for them especially where repetitious use is required. I too have seen threads in alum give up after a couple times. I like EZ-lok better than helicoil though but in alum I imagine heli's are good, maybe even better as they have less thermal mass of dissimilar materials????

[satyak]

Helicoil thread repair system a reliable technology

HeliCoil System for Thread Repair & Preventive Maintenance of plastic moulds , machinery , soft metal assembly and all electro-mechanical equipment.

The HeliCoil System is for creation of Stronger & Longer lasting threads while Designing a component or Repairing of component having damaged female threads.

WHY USE HeliCoil

• Create Stronger and longer lasting threads in soft & light metal components made of Aluminium , Composite Alloys or Plastics & Polymers where internal threads of a component are prone to damage due to operating conditions of the equipment the same are fitted in.

• HeliCoil inserts are made from 18-8 grade cold rolled stainless steel having tensile strength ranging from 1,50,000 – 2,00,000 PSI , Hardness between 43-50 HRC which gives a better description of how HeliCoil inserts can withstand a good amount of assembly stress besides creating a stronger thread in weak materials.

• HeliCoil in stainless steel can be safely used in continuous operating temperatures up to 315 degree C & occasional peak temperature of
425 degree C .

• HeliCoil are cold rolled formed & have a very superior surface finish providing maximum surface to surface contact area , thereby greater clamping action and minimum friction between bolt & female thread flank.

• HeliCoil is Anti-Corrosive & Non- Magnetic
Made of 18-8 grade cold rolled stainless steel it provides a better resistance to corrosion under extreme atmospheric conditions and operational environments.

• HeliCoil reduces bolt failure, breaking & thread stripping

The common known causes of bolt failure and breaking or thread stripping are over torque , thread pitch angle errors , progressive pitch errors, high stress conditions & continuous vibrations.
In absence of HeliCoil , it has been observed that a bolt is subject to an average tightening load of more than 70% over the first two threads near to its collar or over a few threads finding a proper surface contact .
The conditions even get worst when normal machined threads are associated with threads having pitch errors and above adverse conditions.

HeliCoil stretches itself to compensate for pitch angle errors & progressive pitch errors thereby providing a better surface contact & more even load distribution to prevent the bolt failures.
HeliCoil has a “designed-in” radial & axial elasticity.
This allows the shearing load to be transformed into favourable hoop stress or radial load towards the full length of the insert. With result the load gets more evenly transformed over the entire length of the threads of a bolt, thus bolt breaking & thread shearing is significantly reduced.

HeliCoil - A Gift to Designers
The above mentioned compensation & even load distribution features allow a superior reliability of assembly and without compromising on performance Allows the Designers to choose a bolts of lower strength , bolt of alternate metals, bolt having lesser length , creating possibility of lower torque requirements for soft metals , retaining strength of components having less wall thickness.

HeliCoil inserts are also available with a locking coil for thread locking of screws & bolts to prevent loosening due to heavy or continuous vibrations.
Unlike the other methods used for thread locking like adhesives , the locking type HeliCoil is reusable for several bolt opening & tightening cycles .

Use of HeliCoil eliminates most of the given problems as it remains in a compressed state inside the threaded hole & holds tightly to the wall despite variable heat expansion , vibrations & high impact conditions. HeliCoil doesn’t get loose by repeated tightening or opening of bolt .
The HeliCoil is installed by a tool which compresses it at first to get installed in a threaded hole after which it sits tightly against the thread flanks , the only way it can be taken out is by using a tool which reduces it in diameter during extraction.

HeliCoil Cuts on outsourcing repairs , reduces equipment down time & avoid expensive conventional methods in practice.
Helicoil is an easy to use good technology & one could do it on own
at a low cost.
E-Mail : business@noblefix.com
Web Site : www.noblefix.com