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helicoil or thread repairs

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by cats, Nov 21, 2005.

  1. i was led to beleive there a mob that does on site helicoiling or thread repairs ..... i cant find em . ...anyone have had dealings with someone like this ????


     
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  2. In the last 5 years or so i havent come across any body who does this on site but really it is so simple to do you only need the kit which is available from any Repco branch or Bolt bloke supplier.

    If you can drill a hole straight and tap a hole the job is 75 % there use wd40 to lube drill and make sure that the tapped hole is clear of swarf/chips and follow the instructions in the top of the box.

    one thing is say M6 is an insert x 1D so helicoil will be 6mm long M6 X 2D is 12mm long M6 x 1.5D is 9mm long.

    Do a practice run on a piece of scrap first.

    PM me if you need any more help
     
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  3. yes thanks for the tip bruce ... its going to b very difficult .. as its a cylinder head exhaust bolt hole .. and its right next to a frame rail .... theres only about 5 mm clearance ... and if thats not enough .... it will have to be drilled with a right angle drill .............. that or remove the front end .. not an easy task on a gsxr 1100 that needs to b hung .... even then its touch and go as to weather the engine has to be moved in the frame .. thats y i was looking for someone that was somewhat expert at putting the lil suckers in .... and a bike shop i had called said there was a mobile crowd ... but didnt have the number ...
     
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  4. 2 ways to get around it...
    1) Don't drill the hole out. Get a pack of JB-Weld from engineering/ industrial supplies shop. Use a long bolt of the same size and the JB-Weld to "cement" it into the worn thread. YES...it will hold and the stuff can stand the temps of exhaust ports. Let cure for 24hrs, then cut the bolt-head off, leaving about 2cm of thread, use a washer/ nut to fit the headers.

    2) Get the next-size-up-imperial bolt (2 of them), coarse thread type, as they have a higher pitch and provide more bite into the alloy.
    With a hacksaw, cut 3-4 shallow grooves AGAINST the thread (lengthwise with the screw). Heat screw over open flame until redhot, then dump it into a bowl/ cup full of Diesel. The material is now hardened.
    It's a perfect tap now to recut the thread, the hacksaw-grooves provide extra bite and remove swarf. Use the bolt to slowly cut a new thread, half-to one turn at a time, remove bolt, remove debris...finish until the bolt binds solid (carefully feeling the point).

    Use the 2. bolt to fix headers.

    Method 2 is also fine for tapping new sump-plug threads, "tipping" the cutting-bolt with bearing grease to catch any swarf that's pushed up into the engine case. Remove debris after each 1/2 to 1 turn, recoating the tip of the bolt with fresh grease each time.

    cheers
     
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  5. Can't compete with Glitch's reply, but I've had a mobile mechanic (Lube Mobile or something) come out and fit a helicoil. Did a fine job, although he was working on a Torana, not a bike.
     
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  6. Now I know where the stripped thread is you can hire a right angle drill makita cordless from most good tool shops i dont know where you are but all tools in Mordialloc will hire them they are quite small and will fit in that area

    I dont whant to knock Glitch Oz but do not bodge / fit imperial bolts to ally castings its one thing to look for when buying a second hand bike besides they are not strong in pressure diecast ally castings they actually require less torque to strip.

    A Helicoil is actually the best solution for high stress fastners when torqued up the wedging action of the coil improves the torque capacity by 20%

    And can be removed and replaced when stripped
     
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  7. i might have found an easy solution.... as standered the exhaust bolt only uses about 7 mm of thread .... i just wound one right into the head and there was only about 3-4 mm protruding....so its posable theres another 10 mm of good thread so iam going to try a longer bolt and maybe a washer or 2 to take up the slack .. winding the longer bolt into the head till it backs home............. hopefuly its been trheaded all the way to the depth of the hole ...and theres enough good thread left to bite up ..... only going to cost 50 cents and 3 washers ... and u wouldnt pick it ... and in future nwhen heads off fix it properly
     
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  8. Imperial or metric doesn't matter...over-torqued they both strip a thread the same way/ same point, no diff at all.

    Exhaust bolts and sump-plugs aren't exactly high-torque fastenings...
    typically between 10-25nm, depending on make/ model etc
    Helicoils also require a certain "wall-thickness" as a stripped hole has to be drilled out considerably to fit the Helicoil....not practical in quite a few applications.
     
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  9. Helicoils also require a certain "wall-thickness" as a stripped hole has to be drilled out considerably to fit the Helicoil....not practical in quite a few applications.[/quote]

    As I said Oz I dont mean to knock what you have said,

    but Did you mean Keenserts ie M10 for M6 ?? solid thread repair insert Dia 10mm
    or
    Helicoil / Recoil at Dia 7.3 mm dia for M6.

    There are many efficent ways these days to correct a stripped thread properly.
     
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  10. well thank u know what ....... it worked ............ got a 45 mm cap screw ...which is 15 longer than the standered ones .... and with 1 washer ... it pulled up phewwwwwwwwwwwwwwww saving a lot of work and expence ... but thanks for all the suggestions ... much appriecated.... its amazing what a clear head and an overnight break will do .... i hadent given the longer bolt a thought last night
     
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  11. Great news mate, congratulations just remeber dont pull it up toooo tight though :LOL:
     
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  12. As said, depends on the application/surrounding "meat". A 7.3mm hole in a 9mm OD alloy-necked extrusion (designed for M6 bolt) with a specified torque of i.e. 35nm is dodgy in my opinion...


    A 1/2 inch coarse thread sump-plug replacing a machine-thread 12mm into alloy is a $5 job compared to an $80++ Helicoil kit, just as proper, just as effective, only requiring a different sized spanner/socket after.
    Done it on 2 Posties recently, no probs at all even when the specced torque was doubled.
    Engine-internals-threads would be a different matter though...

    [edit spelling]
     
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  13. For an m6 helicoil drill 6.3 mm dia = Core Dia
    Helicoil Pitch dia is 6.8 mm Major dia is 7.3 thread installed.

    Sorry to be nit picking but my other hobby is my Machine shop where i enjoy machining Cranks gearboxs transmissions etc and rebuilding repairing other enthusiasts from long ago butchery
     
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  14. the mobile guys name is the stud doctor!! [melbourne]
    he does a good job and his prices are fair!
     
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  15. thanks ... wish i had known that 2 days ago
     
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  16. Sorry to make this thread live again..

    Anyone has contact for stud doctor? I couldn't find it in yellow and white pages?

    I have a stripped thread hole which need to be fixed.. :D
     
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