On Dec 23, 10:08*am, Jo wrote:
This may be more of a car question, but I couldn't find an auto repair
group to ask. I need to pickup a last minute Christmas present for my
dad. I was going to buy him a dog-bone socket wrench. I'm not sure if
I should get the SAE or metric. I really don't understand the
difference between the two. Any suggestions? If it helps, we live in
the U.S. and most of the cars he works on were made between 1988 and
2004 with one being made in the 70s. The brands of the cars/trucks are
mostly Chevrolets and Fords.

SAE = inch
metric = mm

Two different ways of measuring things. SAE is used primarily in the
USA, while metric is used by every other country in the world. You
would learn this in elementary school.

Reality is to work on a modern vehicle in the USA, you need BOTH.

The government tried to switch us over to metric back in the
1970's-1980's and the people summarily rejected the idea. Since then
metric has been slowly creeping into everything mechanical.

It works out great for tool vendors, because you now need to own two
sets of wrenches instead of just one.