Thread: 3/8 drive sockets. Why?

Just occasionally there are tight bolts in the 10 to 14mm sizes (including small-head style bolts) that are too tight for 1/4 drive and insufficient access for 1/2 drive. Starter motor mounting bolts spring to mind. I have a few 3/8 drive sockets, a 50mm extension and an adaptor for 1/2 drive but rarely use them.

You use them a lot working on motorcycles. That's why I've got mine.

Cars are probably using smaller fasteners these days as things are engineered "lighter" and 3/8 drive is probably becoming more applicable.

Removing a waterpump or the like is probably easier swinging a 3/8 drive setup rather than a 1/2 drive setup.

With less weight you probably get more feel torque wise as long as things aren't super tight.

3/8- 1/4 drive socket set is my most used set. Far to many people get to heavy handed useing 1/2 drive socket sets and wonder why the bolts keep coming loose. At least upto 10mm 3/8 drive is all you need
cheers
blaze

Have had similar experience, then through my son, who plays with helos full time, got introduced to 3/8" drive. I rarely use anything else now either on the P38 or wife's Astra AH. The only time I have used the 1/2" drive stuff is with a torque wrench...but even then I am now using 3/8" with an adaptor for most stuff.

A decent set of Sidchrome stuff I bought in 1971 is still a pleasure to use on the odd occasion...like on a 1970s TR6 belonging to a mate!!!

The rule of thumb I was told was..
1/4 drive for small motors.
3/8 drive for motor bikes.
1/2 drive for cars.
3/4 drive trucks.

I don't have many 3/8 drive sockets but being thiner walled they do get into the tighter places.
The fear factor of knuckle damage on tight bolts does exist though
The short handled 3/8 rachet does come in handy in confined spaces for the initial "nip up" before using a ring spanner.

On many late model outboards a 3/8 is required to get into the confined spaces. The 1/2 kit is just slightly too big.

I'm not convinced about access - as long as the O.D. of the socket is bigger than the O.D of the driven part of a 1/2" drive socket it should make little difference, which means it's a vey small range (as was stated, 10-14mm or so) that is involved. I can imagine the situation, but I've never encountered it. And buying a socket set to use only 8 or so sockets (total for metric and imperial) seems expensive!

I've also worked on many motorcycles, and not yet found anything I couldn't do with 1/4" or 1/2" or a spanner! I can't see how a 3/8" drive would give any better feel for torque, other than if a very heavy drive were horizontal (for maximum effect) on a very light fastener, but then I'd be using 1/4" drive anyway.....

The concept that vehicles are becoming less heavily engineered and so are not requiring 1/2" drive is possible, and perhaps a "motorcycle only" mechanic might get away without 1/2" or heavier, but I still find it hard to see a need for all 3 sizes. And if you don't need all three, then surely it's the least useful "compromised for everything" size that isn't required.

1/4" is small and fiddly.
1/2" is big and chunky.
3/8" is just right.