Thread Tap Extension?

  1. mymini86

    mymini86 Life is a sum of all your choices.

    Messages:
    75
    Location:
    Derby
    After replacing the injector seal on the van, the clamping bolt has partially stripped its thread, so I will need to tap and Helicoil a recessed M6 (possibly M7) hole into the cylinder head.

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    The recess is approx 125mm deep, and I only have the standard shorter style tap, I have found some long M6/M7 on eBay for approx £15 each, but rather than buying individual ones I was just wondering if anybody knows where I can get some generic extension to use with the shorter tap?

    Similar to this below

     
  2. 8ob

    8ob Forum Supporter

    Messages:
    3,836
    Location:
    moscow on thames
    On this type of jigger pokery I use an old 1/4" drive socket and beat it onto the tap, then just use the 1/4" drive extension bar.

    Bob
     
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  3. Pete.

    Pete. Member

    Messages:
    8,057
    Location:
    Kent, UK
    On many taps you can turn the 1/4" extension backwards and use the square to turn the tap, put tap wrench on the other end.

    I also made an extension for a recoil spark plug repair tap by welding a scrap 1/4" socket to a piece of rod so the square end was showing, and weldeing a nut on the other end for turning it. The square didn't quite grip the 6mm square end of the tap so I cut the four corners with a 1mm disc and then welded them again. The welds pulled it in and it then gripped the tap well.
     
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  4. The_Yellow_Ardvark

    The_Yellow_Ardvark If in doubt ask.

    Messages:
    10,331
    Location:
    UK
    Tap a nut onto the square of the tap.
    Use a socket and wrench to turn it.

    Coat the tap in heavy grease. makes it easier to keep the swarf under control.
     
    Last edited: Jul 13, 2019
    winchman and slim_boy_fat like this.
  5. Bill Edwards Member

    Messages:
    4,789
    Location:
    Scarborough, North Yorkshire
    Mercedes CDI...?

    Be careful not to be rough when you bottom out the tap as I’m told the water jacket is quite easy to break into, so be extra careful.
     
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  6. Sean Another 602 fan

    Messages:
    1,059
    Edinburgh
    Carboot sale, cheapo chineese socket set ( imperial) 12 point sockets keep the ones that fit on the square shank and bin the rest( scrap bin for future bodgery) so your not tempted to use them

    Normal extension bar and a tommy bar/ t handle
     
    8ob likes this.
  7. carbon

    carbon Member

    Messages:
    1,105
    Location:
    S. Glos. U.K
    Not sure what they are classed as but had two in a socket set, one is 1/4” squ both ends think the other is 1/4” to 10mm squ have used that on taps in deep holes before
     
  8. premmington

    premmington Member

    Messages:
    1,056
    Location:
    Norfolk
    You can buy extra long taps for this job - not sure where I got mine - in a purpose made kit I think - with the thread repair inserts.

    The inserts have a hex in them - to screw them down into the - head/bigger hole.

    Avoid the water jacket - as Bill Edwards has already noted.
     
  9. Shox Dr

    Shox Dr Chief Engineer to Carlos Fandango

    Messages:
    13,389
    Location:
    East Yorkshire
    There are 1/4-3/8 drive sockets available to take Sq taps. There’s a magnet in side to hold the tap as well.

    image.jpg
     
  10. Hitch

    Hitch Moderator Staff Member

    Messages:
    11,877
    Somerset
    Or there's adjustable tap wrench style sockets about. Irwin do them, 2 sizes covers about m5 to m12 from memory.
     
  11. awemawson Forum Supporter

    I use a long tap wrench - Eclipse E145 iirc E145.jpg
     
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  12. Maker

    Maker nEw mEmBeR

    Messages:
    6,550
    Location:
    Don't ask questions
    You can drill a hole in the end of a round bar that'll fit the square of the tap and cross drill it for a set screw to hold the tap in place, only needed it once but it worked very nicely.
     
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  13. rory1

    rory1 Member

    Messages:
    1,042
    Location:
    Macclesfield
    I do the similar but drill a interfearance fit hole, warm the round stock up and knock the tap in.
     
    premmington and Maker like this.
  14. zeppelin builder

    zeppelin builder Member

    Messages:
    1,090
    Location:
    peoples republic of scotland
    ive tig welded round ms bar with 309 to a tap where i had no side clearance ,worked well but was only on ally casting
     
    premmington likes this.
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