30-12-2019, 07:58 PM
A school colleague's father was an old world class conscious very proud Pom worker who had spent time in a workshop. He reckoned the only virtue of the then American AF hardware (SAE,UNF) was that the nuts could be easily split off with a chisel!* It is notable that the standard metric threads closely approach BSF in proportions. From a 1920s book seems BSF was first proposed in 1905. Many cars had their own threads prior.
Quite a few publications have a table of all the various threads and pitches and tapping sizes in progression. These charts are very useful for identification and for remedy work, esp where not too critical.Over short lengths can get by with slight pitch differences.
The table of spanner openings appeared in many Haynes manuals. Handy for selecting a socket which can be tapped onto manifold nuts etc on other makes corroded smaller and otherwise damged.
* he also reckoned the only virtue of American raised v lathe beds was tht workers could not sit on them.
Quite a few publications have a table of all the various threads and pitches and tapping sizes in progression. These charts are very useful for identification and for remedy work, esp where not too critical.Over short lengths can get by with slight pitch differences.
The table of spanner openings appeared in many Haynes manuals. Handy for selecting a socket which can be tapped onto manifold nuts etc on other makes corroded smaller and otherwise damged.
* he also reckoned the only virtue of American raised v lathe beds was tht workers could not sit on them.