Torque Specifications
The recommended fastener torque values are listed in the following tables. For
critical applications, as determined by Toro, either the recommended torque or a
torque that is unique to the application is clearly identified and specified in the
service manual.
These torque specifications for the installation and tightening of fasteners shall
apply for all fasteners which do not have a specific requirement identified 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
affects 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. Torque values
may also have to be reduced when the fastener is threaded into aluminum or
brass. The specific 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 off fastener 1/4 of a turn.
Measure the torque required to tighten the fastener until the lines match up.
Fastener Identification
Inch Series Bolts and Screws
g272208
Figure 1
1.
Grade 1
3.
Grade 8
2.
Grade 5
POWER CLEAR® 721/821 Snowthrower Service Manual
Page 2–3
Specifications and Maintenance: Torque Specifications
3438-776 Rev A
