From: Bjorn Brandstedt (super_deuce@hotmail.com)
Date: Fri Sep 20 2002 - 14:55:54 PDT
Tom,
I just returned from my garage. Tested a commercial grade bolt and it failed
at about 25 ft-lb. The grade 8 cap screw was tightened to 75 ft-lb and came
apart afterwards without any sign of failure.
My manuals specify 45 to 50 ft-lb for grade 8 and 20 to 23 for commercial
grade.There is a difference between wet (oiled) and dry, these numbers apply
to dry assemblies.
Back to the spindle on the truck, after i discovered the problem with the
nuts, I called the Rockwell tech line (the manufacturer of the axle) and was
told that the nuts must be grade 8 and torqued to 45 to 50 ft-lb.
I believe that the manual calls out lock washers also, however, a properly
torqued bolt assembly doesn't need lock washers, the tension in the bolt
(cap screw) is what holds it together.
When a lock washer is used and the assembly tightened, the lock washer does
nothing, it only works for a while after the assembly has loosend up and
then it's too late any way. Torquing is VERY important. Most cap screw
assemblies on the deuce do not use lock washers.
Bjorn
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This archive was generated by hypermail 2.1.4 : Wed Apr 23 2003 - 13:21:22 PDT