Coarse vs Fine Threads

Coarse Threads

For most applications, course threads offer these advantages:

• Easier and faster assembly, providing a better start with less chance of cross threading.
• Nicks and burrs from handling are less liable to affect assembly.
• They are less likely to seize in temperature applications and in joints where corrosion will form.
• Less prone to strip when threaded into lower strength metals.
• More easily tapped in brittle materials and or materials that crumble easily.

Fine Threads

Fine threads may make for a superior fastener for applications with specific strength or other requirements.

• They are about 10% stronger that coarse threads due to their greater cross-section area.
• In very hard materials, fine threads are easier to tap.
• They can be adjusted more precisely because of their smaller helix angle.
• Where length of engagement is limited, they provide greater strength.
• Thinner wall thickness can be used because of their smaller thread cross section.