What is the difference between AF, Metric and Whitworth sockets ?

Question

I am looking to buy socket tool kit to do mechanical jobs. Type of sockets available are AF(Accross Flat), Metric and Whitworth. I am not sure which one I require.

Answer 1

It all depends what you plan to do. All new stuff will be metric (assuming you are in the UK). Older stuff will be imperial (AF). I personally recommend a cheaper brand, everything set. There are occasions when nothing seems to fit even on new metric and having the full range allows you to find something. The cheap set also gives you the option to hammer a socket onto that stripped bolt head without feeling guilty.

Go and buy that expensive metric set later when you have some spare cash.

Answer 2

It really depends upon where the equipment you want to work on was made and how old it is.  Metric is fairly universal nowadays on most things.  Whitworth is encountered very infrequently, it is the old UK standard, along with BSF (British Standard Fine).  AF (across flats) was the sizes used on the cars built in the UK when Leyland was still around.  They will all fit each other to some extent, but not properly.  In my opinion, go for the metric.

Answer 3

Steve C has given detailed answer.

If you are in India, (Since this is YIA) go for Metric, which is the universal system except USA.