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 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.