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  1. #1
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    Default fixing broken exhaust studs...

    this is on a 04 sporty head, but i'm sure it applies to a bunch of other heads. i broke a stud off, then broke an extractor off in the broken stud. double busted. i hate those things. i bashed it up with a cold chisel, i torched it, welded shit to it, all that. it ain't coming out. so what i'm wondering is....

    Is it bad manners to just drill and tap some new exhaust studs? there's plenty of metal for it. might have to tweak the flange, but it should work fine. lemme know what u think....

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    Your best bet is to remove the head,
    take it to an engineering shop for ''WIRE SPARK EROSION''.
    done properly it will even save the threads,....
    the extractor is hardened so you shouldn't be able to drill it now.

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    EDM is what to ask for in the US. It's dandy for hardened metal removal.

    https://en.wikipedia.org/wiki/Electr...arge_machining

    Here's one in Savannah: http://www.plousemanufacturing.com/w...annah-wire-edm

    If they want too much money I'd look for a takeoff head on Ebay.

    I always anti-seize exhaust fasteners during assembly. Dry threads invite corrosion invite broken parts.

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    Cobalt drill bit and one of these just might do the trick .... ??

    Click image for larger version. 

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    Could try a four flute end mill too ...

    Last edited by Dragstews; 10-29-2018 at 12:38 PM.

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    Note the cutter Dragstews posted is a "center cut" end mill. That's what ya want, preferably solid carbide. Carbide will cut the extractor but is delicate and can snap if you side-load the end mill. You can find correct speed and feed (which you can't control precisely with a common hand drill) online, but with a busted screw extractor in the head I'd pull the head either way.

    With the head off it's easier to take it to a machinist so their milling cutter (or EDM tool) and your head will be held securely. The plate with guide bushing could work for an experienced operator but experience in this case includes learning from what breaks.

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    You pretty much screwed the pooch for doing a home repair once that extractor broke off in it. The bolt-in guide is only good for drilling out a broken bolt or stud, not hardened extractors. And yes, the head needs to come off.

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    In future just drill and repair with a thread repair insert. Don't try to extract the stud. It was stuck enough to break off in the first place.

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    That's why I haven't used an easyout in 40 years! If they break it's always flush to the bolt being extracted! I use an allen wrench driven in with a bfh. If I manage to brake them, they always break in the bend so there is plenty of room for vicegrips and a slide hammer.
    Now that its broken I have never been able to drill a easyout with cobalt but sometimes solid carbide in a really solid drill press or better yet a mill. Shame ya don't have an iron head I burned lots of bolts taps and easyouts out of 312 ford heads with a cutting torch, can't cut cast iron with a torch.But you can cook enough steel into an aluminum casting to ruin it.
    If you have a drill press or mill I have a 3/8" solid carbide drill bit leftover from drilling AR plate on HUMMWVs that I would lend as long as you have a decent way to hold it steady so I have a 50% chance of getting it back
    Or the internet is full of homemade spark erosion or EDM machines. http://mikesworkshop.weebly.com/a-sp...apparatus.html
    Dusty

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    for future information as it's too late now you have an easy-out sheared off,
    also not knowing what type of easy-out you used,
    but at engineering college 40+ years ago we were told NOT to use the usual type
    with a tapered left hand spiral thread as the valleys of the cut left hand spiral themselves
    are a manufactured weak spot, that will 9 out of 10 times snap off on you.
    that the ones to use are in fact square tapered ones with sharp flutes on the edges
    that cut into the wall of the hole you drill into the sheared bolt with a light Tap with a hammer,
    They are far less likely to shear as there are no machined weak spots on them and should not try to expand the broken bolt making it even tighter and harder to remove which the spiral types do.
    available on ebay or good Tool supply shops....
    Attached Thumbnails Attached Thumbnails s-l1600[9].jpg   s-l1600[3] (2).jpg  
    Last edited by tzienlee; 10-30-2018 at 3:10 AM.

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    Quote Originally Posted by tzienlee View Post
    for future information as it's too late now you have an easy-out sheared off,
    also not knowing what type of easy-out you used,
    but at engineering college 40+ years ago we were told NOT to use the usual type
    with a tapered left hand spiral thread as the valleys of the cut left hand spiral themselves
    are a manufactured weak spot, that will 9 out of 10 times snap off on you.
    that the ones to use are in fact square tapered ones with sharp flutes on the edges
    that cut into the wall of the hole you drill into the sheared bolt with a light Tap with a hammer,
    They are far less likely to shear as there are no machined weak spots on them and should not try to expand the broken bolt making it even tighter and harder to remove which the spiral types do.
    available on ebay or good Tool supply shops...……….
    Yep they are better but if they brake it's inside the bolt. Like I said 40 years using allen wrenches, they always brake in the bend.
    Dusty

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