Grease Nippel in Inch Threads - BSW, UNF and Design Types Overview

Grease fittings are small components with a big impact - they ensure reliable lubrication of bearings, joints, and machine parts. Especially when working with machinery from the UK or the USA, knowing the correct inch thread is essential.

The Most Important Thread Types

BSW (British Standard Whitworth) - the British thread

• Flank angle: 55°

• Cylindrical Whitworth profile

• Typical size: e.g. 5/16" BSW (18 threads per inch)

• Widely used on older machinery and in plumbing applications

UNF (Unified Fine) - the American fine thread

• Flank angle: 60°

• Part of the US Unified Thread Standard

• Typical sizes: 1/4"-28 UNF or 3/8"-24 UNF

• Commonly found on American vehicles and hydraulic components

Quick reference of common sizes:

The Three Design Types - For Every Installation Situation

Besides the thread, the design type determines practical usability:

• Straight - the classic choice for easily accessible lubrication points

• 45° angled - for locations with limited side clearance

• 90° angled - the solution for extremely tight installation spaces

All three angled versions are available with both BSW and UNF threads.

In a Nutshell

• BSW for British and older machinery

• UNF for American vehicles and equipment

• A specification like "1/4"-28 UNF, 90°" clearly defines both thread type and design

A small but well-stocked inventory of common grease fitting variants saves time and ensures that maintenance work can be completed quickly and with the perfect fit.

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