How can I tell the difference between standard or metric bolts?

Question

I would like to do some auto work and all ready own standard ratchets. From what I read, most 90's and on vehicles are metric. How can I tell the difference between the two, especially when the bots are fastened in the deepest, darkest, dirtiest parts of my vehicle?

Answer 1

You really need a brain to do "auto repair work" and asking that question shows how much you have to learn.

If your "standard ratchets", as you call them, will not fit properly, then they must not be standard ratchet size. The danger of you coming across BSW, BSF, BA, is almost nil these days.

If you are afraid of the deepest darkest dirtiest parts of your vehicle you should not be attempting to go in there, you may find foreign boggarts.

Answer 2

Find a bolt right there under the hood and try a metric and a standard on it, what ever fits better will tell you what the rest of the car is.

Answer 3

You find the wrench that fits and see what it is.  

Answer 4

i guess you really need a good eye to tell the difference

Answer 5

The only way you will be able to tell is having a set of metric sockets and a set of imperial sockets and see if you can feel which socket is the right one .