Hexagon Head Cap Screws
Metric & Multistandard Components Corp. item number #7931 is for British Hex Head Cap Screws. The British Whitworth thread form is available in three different thread series BSW (British Standard Whitworth), BSF (British Standard Fine), and BA (British Association). In general all three thread forms officially became obsolete in April of 1974 when the formal 10 year conversion to the true metric system was completed.
Although British BSW and BSF fasteners are called out by fractional diameter and threads per inch similar to American fastener threads they differ in the thread form. Both BSW and BSF have full Whitworth thread form which is a 55 degree thread angle with radiuses root and crest.
The third series BA (British Association) threads have a 47 ½ degree thread angle with radiuses root and crest. The BA series are not available in fine series and are called out by a number size. The numerically lower number is the larger size; example 2BA would be larger than 4BA.
Typically British Hex Head Cap Screws are available in heat treated steel that is similar to U.S. Grade 5. Other materials such as stainless or brass are available. Please contact a Metric & Multistandard Components Corp. customer service representative for further information and for all of your British needs.
Although British BSW and BSF fasteners are called out by fractional diameter and threads per inch similar to American fastener threads they differ in the thread form. Both BSW and BSF have full Whitworth thread form which is a 55 degree thread angle with radiuses root and crest.
The third series BA (British Association) threads have a 47 ½ degree thread angle with radiuses root and crest. The BA series are not available in fine series and are called out by a number size. The numerically lower number is the larger size; example 2BA would be larger than 4BA.
Typically British Hex Head Cap Screws are available in heat treated steel that is similar to U.S. Grade 5. Other materials such as stainless or brass are available. Please contact a Metric & Multistandard Components Corp. customer service representative for further information and for all of your British needs.