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Torque Wrench adapters...
In message <199702261510.AA01889@igw.fmc.com> firstname.lastname@example.org (CHRISTOPHER BENDER) writes:
> I've been listening to a lot of talk about this subject recently, and
> so far only one guy has got it right.
Two, actually. One being me.
> I forget his name, but he concluded his proof with "Q.E.D.," ...
> A guy claiming to be a mechanical engineer tells us
> that the torque calculation has nothing to do with the length of the
> torque wrench. Hello?!? This is simple statics! How long ago did
> you have the course??? Well, I'm getting fed up with the ignorance,
> and I am gonna take a stab at it.
And get it wrong ...
> It's real simple. Torque varies linearly in a cantilever beam. A
> wrench is just that: a cantilever beam. Torque is theoretically
> maximum at the base (the fastener being torqued) and is zero at the
> point of application (The end of the wrench that you push, pull, stand
> on, etc.). It varies linearly between the two ends for any point of
> interest in between. So, when you use an extension, you have to scale
> up the torque LINEARLY by the ratio of the total length (wrench plus
> extension) to the length of the wrench alone.
Wrong so far, but carry on.
> But what does this mean to us Audi people trying to use tool 2079?
> Well, it means, that the torque specification given by Mr. Bentley is
> conceptually flawed. To specify a torque of 258 lb-ft with tool 2079,
> but without specifying the torque wrench to be used, is wrong because
> they have to make an assumption of the length of your torque wrench.
No. Mr Bentley is not actually the source for this information - it's Mr
I quote from "Reparaturleitfaden Audi quattro 5-Zyl. Einspritzmotor", Audi
publication number 000.5148.29.00, Reparaturgruppe 13, Absatz 13-6:
"Anzugsdrehmoment 350Nm mit Sonderwerkzeug 2079 und 2084
Anzugsdrehmoment 450Nm ohne Sonderwerkzeug 2079"
350Nm is 258 lb ft, and 450Nm is 332 lb ft. Now - I don't personally care a
flying **** _HOW_ Audi reached these values - but both are documented for
the I5 engine. 400 lb ft is 20% over-torque, assuming that your torque wrench
> I'm sorry if I'm sounding rude, and I hope you all will keep the
> flamage to a minimum, but I have just been hearing way too much on
> this relatively simply subject, and I am getting tired of it.
Me too, especially from amateur applied mathematicians.
Oh, and Q.E.D.
Committee Member, UK Audi [ur-]quattro Owners Club