The GOOD shops have a torque stick instead of an extension bar, it
breaks loose at a specified (but somewhat inaccurate) measurement. Then
torque it up properly by hand with a calibrated torque wrench. The
mediocre shops use the torque stick alone. The bad shops have a bubble
gum brain impact wrench jockey pull the trigger until it is "good and tight"

I don't look down on a shop that uses an impact wrench for assembly as
long as they had start the bolts and had torque them afterward. It does
save a lot of time when doing a lot of similar bolts eg on the engine.

Mark Rand wrote:
On Sat, 23 Feb 2008 21:00:11 -0500, clare at snyder.on.ca wrote:

I never reduced the pressure on my impacts from the 150 shop line
pressure. Mine DID have a "power" adjustment that allowed me to dial
the wrench back for assembling, and dial it up for dissassembling.


/RHETORICAL
How do you get accurate torque when assembling with an impact wrench?

The wheel nuts on my car require 81lb-ft of torque (put the wheels on today
after a brake job) they assemble and disassemble easily by hand. A shop uses
an impact wrench on them and they don't until they've undone them and re-done
them with a torque wrench! The crankshaft pulley needs 200lb-ft. Also a manual
job, just use a longer handle.


I can understand the use of an impact wrench for undoing truck wheel nuts, but
with anything less than 400 lb-ft I would question the use of power tools for
assembly. Much above that and I would be using a crane and balance. For large
bolts, I would be expecting to use either hydraulic bolts or heated bolts and
a micrometer, per the drawings.
/RHETORICAL


Am I being excessively picky?


Mark Rand
RTFM