T orque Specications
The recommended fastener torque values are listed in the following tables. For
critical applications, as determined by T oro, either the recommended torque or a
torque that is unique to the application is clearly identied and specied in the
service manual.
These torque specications for the installation and tightening of fasteners shall
apply for all fasteners which do not have a specic requirement identied in
the service manual. The following factors shall be considered when applying
torque: cleanliness of the fastener , use of a thread sealant (Loctite), degree of
lubrication on the fastener , presence of a prevailing torque feature, hardness
of the surface underneath of the fastener ’ s head, or similar condition which
af fects the installation.
As noted in the following tables, torque values should be reduced by 25% for
lubricated fasteners to achieve the similar stress as a dry fastener . T orque values
may also have to be reduced when the fastener is threaded into aluminum or
brass. The specic torque value should be determined based on the aluminum
or brass material strength, fastener size, length of thread engagement, etc.
The standard method of verifying torque shall be performed by marking a line on
the fastener (head or nut) and mating part, then back of f fastener 1/4 of a turn.
Measure the torque required to tighten the fastener until the lines match up.
Fastener Identication
Inch Series Bolts and Screws
g272208
Figure 1
1. Grade 1 3. Grade 8
2. Grade 5
Specications and Maintenance: T orque Specications Page 2–4 2000 Series Z MASTER®Service Manual
3460-328 Rev A