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Ever see a hammer bounce? (and a tech question)
When the clamping pressure gets relieved (when you drill the heads off),
the stud usually loosens up to the point that you can turn it out with
your fingers. If not, vice grips work 90% of the time.
The loosening effect has to do with the friction on the threads
themselves. When the bolt is torqued down hard,
The friction force (over the area of the thread contact surface) = normal
force * coefficient of friction. Since it's torqued down hard, the normal
force (clamping force) is high thus the friction force is also high, so
the bolt resists turning.
This is true of course even if the bolt is just lightly tightened.
Drilling the head off a bolt reduces the turning friction (at least in
this incredibly simplified model; many other factors come in to play.. but
friction is a big one when the compressive force on the bolt is high)
-Toby
On Thu, 4 Sep 2003, L F wrote:
> Heck, Erik, if the Vise-Grips won't grip the heads, how do you expect them to grasp the shank?????
> ----- Original Message -----
> From: Erik
> To: Daun Yeagley ; scirocco-l@scirocco.org
> Sent: Wednesday, September 03, 2003 7:43 PM
> Subject: Re: Ever see a hammer bounce? (and a tech question)
>
>
> Um, huh. Do what I did. Grind off the heads of the bolts, pull the T/B, use
> the Vise Grips to remove the remainder of the stud. Then tomorrow after a
> bowl of corn Flakes a good BM, call a Anger Management Hotline. Although I
> had to take some of those classes a few years ago. I'm not so sure the
> classes worked.
>
> Erik
>
>
> ----- Original Message -----
> From: "Daun Yeagley" <vwdaun@yahoo.com>
> To: <scirocco-l@scirocco.org>
> Sent: Wednesday, September 03, 2003 10:33 PM
> Subject: Ever see a hammer bounce? (and a tech question)
>
>
> > It was such a pleasant evening too....
> >
> > I've been having some trouble with the throttle body on the
> > '86 sticking a little in the "idle" position. Solution?
> > Replace it with another TB that's laying around here.
> > Should be an easy 15 minute project.
> >
> > Oh no. Not for me.
> >
> > I figured I'd be reaaaaally careful not to round those
> > little hex bolts, tapping the wrench in with a hammer &
> > all... worked for two of the four. The front two bolts
> > rounded right off without noticable hesitation.
> >
> > Fine. Solution number one, find a slightly larger standard
> > allen wrench and tap THAT in there. Tapped & tapped, got
> > it in there real tight and.... rounded right off, again,
> > without much hesitation.
> >
> > Solution number two, vice grips. Not a chance in hell,
> > just slipped off the bolt.
> >
> > Ok, try solution one again. Tapped & tapped and....
> > threw the hammer off into the grass next to the car. How
> > in the HELL it bounced the way it did I haven't a clue, but
> > it proceeded to go airborne about six feet and into the
> > living room window.
> >
> > F*CK.
> >
> > I gave up for the night.
> >
> > Does anybody have any solutions to the throttle body
> > dilemma? I so far have two very rounded bolts still firmly
> > stuck in the intake manifold, and of course, a living room
> > window to replace.
> >
> >
> > =====
> > Daun Yeagley - Wilmington Ohio
> > '81 S, '85, '86 & '88 Sciroccos, 90 Passat Wagon, '56 Cessna 172
> > For Sale: '80 Scirocco S, '81 Scirocco, '82 Scirocco.
> > "I'm not always right, but I'm never wrong."
> >
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