Analyzing structural rigidity, tolerances, and assembly complexity in interference joints vs bolted clearance hole configurations.
A press fit typically requires an interference fit class (such as H7/s6 or H7/p6), demanding sub-micron precision that can only be achieved via CNC cylindrical grinding or precision boring. This exponentially increases production time and tooling wear. Conversely, fastener clearance holes (such as ISO 273 fine or medium) permit looser tolerances, reducing manufacturing complexity. However, to prevent slippage in bolted clearance joints under cyclic load, engineers must guarantee adequate preload (tension), necessitating precise torque control and thread-locking elements.
Parts are joined by pressing a shaft into a slightly smaller mating hole, creating a robust, friction-locked assembly.
Parts are joined via threaded bolts passing through slightly oversized clearance holes, secured by nuts.
Adjust the sliders to simulate structural compromises and identify optimized efficiency thresholds.
William Jackson
Senior Mechanical DesignerFor high-speed rotary assemblies, a press fit is absolutely critical to avoid dynamic imbalance. However, we recently transitioned a heavy bracket to fastener clearance holes with wedge-locking washers because field maintenance was becoming a nightmare. The tolerance stack-up analysis was challenging, but the serviceability improvement was worth the extra engineering hours.