Proper Torque Practice

Torquing Technique

Proper torquing technique ensures every mounting surface has equal mounting pressure regardless of the number of bolts used. 

Circular Pattern

• Use the Criss-Cross Technique when securing bolts in a circular pattern. Perform this according to the following procedure:

1. Tighten 1 bolt until its head is almost snug to the surface, travel diagonally to the next bolt hole and repeat.

2. Once all bolts are almost snug, repeat the same pattern and tighten to the appropriate torque spec.

Rectangular Pattern

• Use the Spiral Tightening Sequence when tightening bolts in a rectangular pattern. Perform this according to the following procedure:

1. Starting with the top middle bolt, tighten the bolt until its head is almost snug with the surface. Rotate downwards counter clockwise to the nearest bolt and repeat

2. Once all bolts are almost snug, repeat the same pattern and tighten to the appropriate torque spec

Torquing Settings

1. Due to the variance in material strength, different torque settings must be applied to different materials.

2. We have no standard torque setting for every bolt, however, if a setting is advised from a Service tech please follow the recommendation closely. 

3. Tighten all bolts by hand or with a driver to “hand tight” unless otherwise specified. 

Torquing Problems

Non-Equal Pressure

• When attempting to tighten a series of bolts without utilizing the Criss-Cross Technique or Spiral Tightening Sequence, there will usually be an uneven amount of pressure across your sealing surface. 

  • This can result in leaks, increased material stress, and part damage

Under-Torque

• Greatly decreases the strength of the assembly and increases the chance of a leak due to insufficient mounting pressure against the O-ring. 

  • In severe cases, under torque can result in bolts falling due to vibrations.

Under-Torque

• Usually results in stripping the threaded hole or snapping the head of the bolt. 

  • Over-torquing bolts along a sealing surface can decrease the effectiveness and lifespan of an o-ring, often causing damage to the o-ring.