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Threads... 750 crankcase studs

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AshimotoK0:
Here  is an update with Pics. Dimpled top of broken off stud with Dremel then  used S/S sleeves and drills and scrap barrels as a drilling guide. 1st hole was pretty concentric (see pic) slightly smaller than M8 tap size. Last week opened hole out to tapping size M8 (6.8mm drill) and could hear crunching as I drilled it presumably bits of treads breaking up. Where do I go from here,, run a tap down it or try to pick bits of the old tread out?  Please don't suggest spark erosion as it is going to cost quite a bit to get done around here plus I hate entrusting rare parts with people I don't know, so it's a last resort really.

Ash.

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BROKEN STUD

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1st Drilling 6.5mm

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DRILL AND S/S SLEEVE

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AFTER DRILLING OUT TO TAPPING SIZE 6.8mm (for M8x1.25 ISO thread)

UK Pete:
Careful picking with an apropriate tool is going to be fiddly but you would be OK. Is there enough meat left to be able to try and twist it out with an ezyout?
Pete

RGP750:
That was my thought Pete

philward:
My experience of using an easyout in this situation is that you will grip the stud wall and push it into the softer casing with the stud drilled out to tapping size. Picking the thread out is the safest bet in my opinion. If the hole is not exactly central, tapping the stud will see the tap take the easiest route and will track towards the casing.
Phil

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