The following points are important for bolt thread modeling:
- The Bolt cylindrical surface/edge should be the contact side. 
- Starting Point and Ending Point of bolt thread (under Bolt Thread Correction), should be on the bolt axis and defined in the global coordinate system. 
- In order to achieve better accuracy, the mesh size in the thread region should be less than the Pitch Distance. 
- We recommend using the projection-based contact Detection Method (Nodal-Projected Normal From Contact). 
- This technique is valid only for standard, straight threads. It is not applicable for nonstandard threads such as tapered threads or buttress threads. 
- The maximum stress in the thread region may vary with mesh density. However, the overall stress distribution remains similar in pattern.