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New to Helicoils and need help

Discussion in 'A BEGINNER'S FORUM (Learn How To Machine Here!)' started by mzvarner, Jun 22, 2017.

  1. mzvarner

    mzvarner United States Active Member Active Member

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    First, i hope I am posting this in the correct thread. i have not posted in a while.

    Back story: A few weeks back i picked up a used 2005 Honda CRF 250R. I wanted to learn to ride, and learn about motors. Ultimately I was looking for, and found a project bike. However, It turns out the lower bolt of the oil filter cover is stripped, and I need to use a helicoil to repair it. The bolt threads are in great shape (ran it through a die to be sure) and measure M7 x 1.0. (but has a 7/16 head?, not metric? weird as all other bolt heads are either 8, 10, or 12 mm).

    So looking for kits it seems m7 x 1.0 is an odd thread pitch, therefore expensive heli coil kit. Will a m6 x1.0 kit work (still expensive)? Should I stick with m7 x1? It is a bummer because there was a kit on amazon for $50 for 5 different sizes, but not including the m7 x 1.0. If I get just the 2 size kits i need its over $50.

    Thanks
     
  2. westsailpat

    westsailpat United States H-M Supporter - Premium Content H-M Supporter-Premium

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  3. Ed ke6bnl

    Ed ke6bnl Active Member Active Member

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    will he need a special tap for the helicoil and tool for installation. I have so far always used thread serts.
     
  4. westsailpat

    westsailpat United States H-M Supporter - Premium Content H-M Supporter-Premium

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    Yes it takes a special tap , also a insert tool . Although I have made the tool in a pinch you just grind half the face off of a bolt so that it locks on the tang . You also have to remove the tang I have munged that operation a few times .
    I don't know why our friend is having problems finding this insert , should be at a auto parts store .
     
  5. mzvarner

    mzvarner United States Active Member Active Member

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    I am not having problems finding them. The issue is the cost. I literally only need 2 helicoils. Each kit is about $45, then I need to purchase the correct bit. The cost is the same at all local parts stores (Napa, Oreiley's, etc.). I was hoping to find a cheaper kit on line, or see if there is a comparable kit a size up or down or SAE. I am cheap, and have a hard time spending about $90 for 2 kits I can only see myself using at this moment. maybe thats just the price to play?
     
    brino likes this.
  6. grumpygator

    grumpygator United States Global Moderator Staff Member Director

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    Why not make your own out of a larger bolt? If so I would suggest pipe thread for the OD with thread locker.
    ...***Just Saying>>>**G**
     
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  7. Ulma Doctor

    Ulma Doctor Infinitely Curious Active Member

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    you could use a 1/4-20 or 1/4-28 helicoil for a bit cheaper

    by the way, 7/16 and 11mm are close enough to be equal in socket size (7/16(.4375")= 11.17mm)
     
    Last edited: Jun 22, 2017
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  8. Old junk

    Old junk United States Active Member Active Member

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    I second what ulma said.i often repair odd ball metric threads with standard helicoils.only down side is to remember it's now different.
     
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  9. WoodBee

    WoodBee Netherlands Active Member Active Member

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    Suggestion from metric part of the world:
    M7 is indeed a odd size and hardly used anymore. If at all possible and you want to keep the bike all metric:
    Drill and tap for m8, which is a standard size. I assume metric taps are available for a reasonable price, or you might even be able to borrow one for your two holes?

    (M7 is a non preferred size, mainly used on older machines/tools. Unfortunately this also includes QC toolholders from multifix)
    Peter
     
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  10. fixit

    fixit United States Active User H-M Supporter-Premium

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    McMaster Carr has a kit with all tools included & 10 inserts for $53.99 #91732A950
     
  11. TORQUIN

    TORQUIN United States Active Member Active Member

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    I agree with the different bolt size idea. If you have enough meat around your hole, find a larger size you can drill it to and don't use a helicoil at all. you can go metric or standard, depending on what you want/what's readily available.
    I went through this on my 6BT Cummins injector pump. A couple of the bolt holes wallowed out from the bolts not being tight enough and the vibration (the solenoid they hold is pretty heavy). The bolt size was 6mm. I calculated that I had just enough metal around those holes to drill it for 1/4-20, so that's what I did. Helicoils are for when there is no other choice, because at that point money is not as important, and I think Helicoil knows it.

    Chris
     
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  12. MozamPete

    MozamPete South Africa Active User H-M Supporter-Premium

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    +1 on just drilling it out to tap M8 and replace the bolt. Much cheaper than a helicoil.
     

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