Exhaust manifold studs Q

[marc_scirocco@yahoo.ca (Marc scirocco Québec)]

I have a brand new cobalt drill bits set. I tried a
smaller size, 1/8. Nothing, hardly any metal came off
after over one hour of drilling. I tried different
bits, nothing.

Cheers.

Marc

 --- Peter <peter@thescirocco.com> a écrit : >
-----Original Message-----
> From: scirocco-l-admin@scirocco.org
> [mailto:scirocco-l-admin@scirocco.org] On Behalf Of
> Marc scirocco Québec
> Sent: Saturday, June 22, 2002 10:00 PM
> To: Peter
> Cc: scirocco-l@scirocco.org
> Subject: RE: Exhaust manifold studs Q
> 
> 
> Heli-coils went in for two of the holes. Now the
> last
> son of a b***h looks like it is a stainless steel
> stud.
> 
> Titanium drill bits did nothing. Cobalt drill bits
> with four points did nothing. Lots of cutting oil,
> low
> speed (+-200RPM), high pressure, and I am down into
> the stud about 1/16 of an inch.
> 
> Any ideas? A machine shop?
> 
> Cheers.
> 
> Marc
> '83 Scirocco
> '88 Scirocco Slegato
> 
> Stainless isn't any harder than the stock hardened
> studs...
> 
> I'd try a new drill bit first... 
> Sometimes they loose their edge before you can get
> them all drilled out.
> 
> Pete
> 
> 
>  --- Peter <peter@thescirocco.com> a écrit : > 
> > 
> > -----Original Message-----
> > From: scirocco-l-admin@scirocco.org 
> > [mailto:scirocco-l-admin@scirocco.org] On Behalf
> Of Marc scirocco 
> > Québec
> > Sent: Sunday, June 16, 2002 8:46 PM
> > To: scirocco-l@scirocco.org
> > Subject: Exhaust manifold studs Q
> > 
> > 
> > Here it is, I am about to install this 4-2 exhaust
> > manifold.
> > 
> > Now, 3 of the old studs are out, no problem. The 3
> > remaining studs broke, with nothing to grab them.
> > 
> > I drilled 2, one of them is gone now, but the
> > threads
> > are shot... And I am sur that it will be the same
> > thing for the remaining 2 studs.
> > 
> > At this stage, I do not care if the new studs ever
> > come out again, so I am thinking about drilling a
> > hole, and welding/gluing the remaining 3 new
> studs,
> > JB
> > weld, or something similar...
> > 
> > Anybody has done something similar in the past?
> Any suggestion?
> > 
> > Cheers.
> > 
> > Marc
> > '83 Scirocco
> > '88 Scirocco Slegato
> > 
> > Using 8mm x 1.25 Heli-coils is how I would fix it.
> > The kit comes with a tap for the steel coil
> threads,
> > you drill the
> > 21/64" hole, run the tap through, the key to
> tapping
> > cast iron is back
> > and forth, back and forth, in very small steps,
> you
> > thread in the thread
> > coil and you are done.
> > 
> > The tough part is drilling the hole in the center
> of
> > the broken stud.
> > A small 1/8" pilot hole in the center of the
> broken
> > stud is a good start
> > and a drill press doesn't hurt.
> > 
> > Peter
> >  
> 
>
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