quattro digest, Vol 1 #596 - Message 22

[John Larson]

Cleaning threaded holes in either alloy or steel with a tap is going to
remove metal, especially with the pretty generic tap and die sets
offered by Sears, Snap on, et. al. Use of graduated tap sets might help,
but the real tool to use is a "thread chaser", which comes closer to
reforming the threads than to recutting them. Especially in softer
alloys, each time a tap is run through the hole there is a resultant
loss in contact area and the ability to hold torque.  I do realize,
however, that cleaning up threads on heat cycled metal such as the O2
sensor hole often requires a tap. BTDT. HTH, John
> 
> Message: 22
> Date: Wed, 6 Dec 2000 05:42:59 -0800 (PST)
> From: james accordino <ssgacc at yahoo.com>
> Subject: Re: Metric taps and dies-O2 sensor fun
> To: urquattro <urquattro at phoenixdsl.com>
> Cc: audi list <quattro at audifans.com>
> 
> --- urquattro <urquattro at phoenixdsl.com> wrote:
> > > then be screwed in by hand.  After 2+ years, it
> > came
> > > out very easily with no metal damage, and I didn't
> > use
> > > that anti-seize compound.
> >
> > IME the OXS comes with anti seize on the threads
> > from the Bosch/Audi ...
> 
> That's also been my experience lately.  10 years ago I
> think they used to come dry.
> 
> >
> > Thanks for the info on the proper tap being
> > available in the standard
> > Crapsman kit ... suppose I should add that to my
> > Chrismas list post haste!
> 
> My wife got me the "standard" metric set for Christmas
> 3 years ago, and a 20 ton press and engine stand and
> hammer puller set and ...  Boy was that a GREAT
> Christmas!  I used the taps so much, I bought the
> large set a few months later.  Great where steel is
> attached to alloy castings.
> 
> Come On Santa!
> 
> Jim Accordino
> 
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