Right thread said
At Evotech Performance, we welcome customer feedback. Most comments are about the exceptional quality of our products and services, and then there are technical queries.
One frequent query is aimed at Evotech fasteners that are supplied with, say, Evotech Main Crash Protection to replace OE engine-to-chassis fasteners. The topic of the query is “rolled threads.”
What’s a rolled thread? Aren’t fastener threads all made the same? What makes a rolled thread on an Evotech Crash Protection replacement bolt more durable? These are just some of the more common questions asked about specialised Evotech fasteners.
For critical mounting points, Evotech produces its own fasteners and usually from 316-grade stainless steel. These fasteners feature a rolled thread as opposed to a machined-cut thread. Simply put, a cut thread via a cutting die has less tensile and shear strength than a rolled thread. This is because the cutting die or tool literally cuts through the steel’s grain flow, whereas the grain on a rolled thread is forced to follow the contours of the thread so the grain, although squished, remains intact as a continuous flow line. The diagram (below/where) clearly shows one attribute of thread rolling vs cut threads.
Rolled threads are achieved much like rolling and squeezing at the same time a small length of plasticine between your thumb and index finger. The difference being is that on specialised thread rolling set-ups, your two digits are known as rolling dies, complete with the necessary thread pitch. Under extreme hydraulic pressure, the rollers literally squeeze the steel to form the fastener thread.
What this means to you as an Evotech customer is we ensure critical fasteners feature rolled threads because they are, as said, much more durable because of their greater shear strength, which means the thread is less likely to strip. Additional plus-points of rolled threads include no waste steel material i.e. swarf, and the thread surface finish is much finer, again aiding thread durability.