27-02-2022, 08:18 PM
An attempt to summarise.
First a little bit of terminology which can cloud issues. A spanner I recognise as a bar of metal with either an open ended jaw at the end or a closed ring. A box spanner being a round tube of metal shaped into 6 flat sided shapes at each end.
Sockets can have their size shown as the measurement across the opposite flats (AF} (More modern socket sets) - OR - the size of the nut they fit.
A nut size is usually given as the diameter of the round bit it screws onto.
The Austin 7 front stub axle has a diameter of thread of 5/8 inches but is a non standard 16 Threads Per Inch (TPI) the form (shape) of the thread being Whitworth with its 55 degree thread angle.
Hence the nut is a 5/8 inch but with a non standard 16 TPI thread. The distance across 2 opposite flats of the 5/8 inch nut is 13/16 inch.
A socket marked 7/16 W (whitworth) can also have the marking 1/2 BS(F)......measuring across the 2 parallel opposite internal flats will give 13/16 inch - the size of the 5/8 nut.
A modern (American terminology) socket marked 13/16 gives the across-the-flats size so is one to use. (my such socket fits nicely in the end of the hub).
A 14mm plug socket measures across the flats as 13/16 inch and is often the thiner diameter hence is good to use.
13/16 inch (0.8125 inches) is 20.6375 mm so nearly 21mm so a socket marked 21mm would also fit our nut but rather slack while a 20 mm socket would not go on.
Dennis
First a little bit of terminology which can cloud issues. A spanner I recognise as a bar of metal with either an open ended jaw at the end or a closed ring. A box spanner being a round tube of metal shaped into 6 flat sided shapes at each end.
Sockets can have their size shown as the measurement across the opposite flats (AF} (More modern socket sets) - OR - the size of the nut they fit.
A nut size is usually given as the diameter of the round bit it screws onto.
The Austin 7 front stub axle has a diameter of thread of 5/8 inches but is a non standard 16 Threads Per Inch (TPI) the form (shape) of the thread being Whitworth with its 55 degree thread angle.
Hence the nut is a 5/8 inch but with a non standard 16 TPI thread. The distance across 2 opposite flats of the 5/8 inch nut is 13/16 inch.
A socket marked 7/16 W (whitworth) can also have the marking 1/2 BS(F)......measuring across the 2 parallel opposite internal flats will give 13/16 inch - the size of the 5/8 nut.
A modern (American terminology) socket marked 13/16 gives the across-the-flats size so is one to use. (my such socket fits nicely in the end of the hub).
A 14mm plug socket measures across the flats as 13/16 inch and is often the thiner diameter hence is good to use.
13/16 inch (0.8125 inches) is 20.6375 mm so nearly 21mm so a socket marked 21mm would also fit our nut but rather slack while a 20 mm socket would not go on.
Dennis