As others have said, Whitworth is the most common size, and some BA for the small electrical bits. It is also helpful to have some spares, especially for the British Association. Also some knowledge of thread pitches is helpful. Generally speaking, British Association is a small, fine thread pitch used for electrical components and things like instrument screws and such. The numbers make sense though they seem to not be as 0BA is the largest and 16BA is the smallest. Whitworth is a coarser thread commonly used on aluminium and soft metal bits. British Standard Fine is (obviously) a fine thread used on steel bits. Drain plugs and pipe fittings can be either British Standard Pipe Tapered or British Standard Pipe Parallel. Then there is the odd one, Admiralty threads, which I believe came to Austin from WW1 experience. I can't remember where these are used, I think the hubs, but someone else may chime in to confirm. To work on the hubs, you'll need a hub extractor and a big spanner with three holes in it to hold the hubs while you tighten the hub extractor. Generally, you won't need a lot of odd sizes, just the standards. I would watch out for poorer made wrenches as I have a set from India that isn't quite the correct size and which is obviously hard on nuts and bolts. Better to buy a used older better quality set than and poorer quality new set. As noted, sometimes you'll find odd things that didn't come from the works. Unified Coarse, Unified Fine and even metric.
Erich in Mukilteo
Erich in Mukilteo