Sure, a tool is just a tool. And component quality, surfaces and bolt prep all affect the tension on the threads. The question, in my book, is whether you are doing the best you can with the tools that are available?

No matter how experienced a mechanic is, torqueing fasteners to very specific range consistently is a real challenge, especially with all the fussy components that are on the market now.

If you took a four-bolt stem faceplate and tightened all the bolts by hand, and then checked them with a decent torque wrench, I think you'd be surprised at how different the tightness was from one another.

Ultimately, I think the bottom line is customer satisfaction and trust. and unfortuanately, especially for a retail business, liability protection. Having a reliable tool that is calibrated an established standard is waaaaay better than saying, "it felt just right" so I don't know why the carbon stem failed.

so..the best scenario? an experienced mechanic AND a torque wrench.

eric
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bikemecca.com

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Message: 3
Date: Tue, 22 Jul 2008 13:56:07 -0700 (PDT)
From: john
Subject: Re: [OBRA Chat] Tool envy: Effetto Mariposa Giustaforza
Torque Wrench

>>>>>The main issue: When torque is applied to a bolt, most of that torque (90-95%) goes
into overcoming friction, only 5-10 % go into preload. That means if the friction
is off a little, maybe a little galling / burr,? or maybe slippery coating, etc,
the pre-load can be off? whole lot (personal testing, off easily by half to double
! ).? Its actually been shown that a experienced machinist / mechanic with just
a normal wrench can be just as accurate. <<<<