Wheel Torque

Duncan Wood quatrro at dmx512.co.uk
Tue Oct 22 22:20:54 EDT 2002

> Help an EE get a handle on this.
> When they (MEs) specify a torque on a bolt, which should set the
> tension along the axis of the bolt do they also add in the coefficient
> of friction between the steel to steel junction of the threads?  The
> rotary motion being converted to linear motion by sliding two inclined
> planes together? Is this why adding an anti seize (lubricant) will mess
> this up?  Is this why you're supposed to torque the bolt in one
> continuous motion?
> Wouldn't anti seize make the bolt tighter?

Yes it does. If you being finicky you also take into account head diameter &
contact angle. 1 continous motion means you're measuring sliding friction
rather than static friction, one of the reasons many bolts are now torque to
angle. If you really care you can measure the preload in the bolts
ultrasonically but it's only a wheel bolt, the numbers where never that
carefully worked out in the first place as they're expected to cope with
some one using the tyre wrench

> --- QSHIPQ at aol.com wrote:
> > Berme:
> > Comments inserted
> > In a message dated 10/22/02 12:35:02 AM Central Daylight Time,
> > b.m.benz at prodigy.net writes:
> >
> >
> > >Ah, come on Scott!  You must be kidding!  Your torque wrench knows
> > if it is
> > >torquing a lubed or dry bolt and thus reads differently because?
> > BS!

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