What Should You Choose: Coarse Threads or Fine Threads?

Screw threads are uniform ridges on the internal or external surface of a cylindrical surface. These threads are helix shaped.  These threads decide how nuts, bolts, and screws maintain integrity when coupled together. Threads are made coarse or fine for various applications. The coarse threads are suited for most applications; however, fine threads are ideal for applications demanding specific strength. So what differentiates these two types of threads?  Read this post to understand the significant difference between coarse threads and fine threads.

What Separates Coarse Threads and Fine Threads?

As discussed above coarse threads and fine threads are ideal for diverse industrial applications. Both have their own set of beneficial features. They are differentiated below on the basis of certain parameters which highlights their potential benefits over the other.

Parameters that makes Coarse Threads Superior

Mentioned below are certain parameters, which makes coarse threads a better threading option over fine threads:

  • Resistance: A coarse thread is longer than a corresponding fine thread. This means there is more material present between threaded flanks. This helps the thread to attain a perfect fit, and avoid stripping and cross-threading. Overall, this leads to safe and secure engagement over fine threads.
  • Plating Buildup: Coarse threads are less affected by plating build-up in comparison to fine threads. This is due to the presence of abundant material between the threaded flanks. Also, coarse threads are less affected by problems like thread interference and gaging, since their plating allowance is less than fine threads.
  • Galling: It is common that coarse thread fasteners are engineered from stainless steel, which makes them anti-corrosive and experience less galling in comparison to fine threads. On the other hand, fine threaded fasteners have a close pitch diameter and perform more rotation, which makes them susceptible to galling.

Parameters that makes Fine Threads Superior

Listed below are parameters which suggest why fine threads are superior to coarse threads:

  • Tensile Area: Fine thread fasteners usually have a higher tensile area than coarse thread fasteners. This improves their tensile strength and makes them 10 percent stronger than coarse threads.
  • Easy to Tap: Fine thread fasteners are easy to tap due to their shallow thread height. This means reduced tapping torque and breakage, especially in difficult materials. These threads are also used for thin walled applications that require fine adjustment due to their shallow height.
  • Helix Angle: The helix angle of fine threads is lesser, which reduces the chances of loosening during vibrations.

As seen, both the threads have a certain advantage as well as disadvantages. Thus, the choice will entirely depend on the situation. If you feel the selection is tricky, it is always better to approach an industrial manufacturer.  Norwood Screw Machine Parts is a well-known manufacturer of industry-grade fasteners, screws, and nuts in coarse and fine threads.

About Norwood Screw Machine

Norwood is a privately owned custom screw machine parts manufacturer. For over 59 years we serve some of the largest corporations to the small company with a new product to develop. Whether a unique item with a one time requirement or a long running contract order with scheduled deliveries, Norwood Screw Machine Parts is the right choice for the job.



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