3/8-Inch Drive Socket and Ratchet Sets

A 3/8-inch drive set is the one most people should own first: big enough for car and equipment work, small enough to get into a cabinet or behind an appliance. Buying one comes down to three questions. Which fastener sizes do you turn? How much room is around them? And is a hand ratchet or an impact tool doing the turning?

Drive size and socket size are two different numbers

The 3/8-inch “drive” is the square hole on the back of the socket that fits your ratchet. The socket’s size, SAE in inches or metric in millimeters, is the opening that fits the nut or bolt. A 1/2-inch socket can have a 3/8-inch drive. A metric set still fits a 3/8-inch ratchet.

To use a socket on a different drive, use an adapter. WBC’s Channellock 3/8-inch female to 1/4-inch male adapter lets your 3/8-inch ratchet turn 1/4-inch drive sockets. An adapter changes the connection, not the strength: it doesn’t add capacity to the smaller sockets.

Pick a set by the fasteners you turn

Count the sizes you actually use, not the pieces in the case. Accessories count toward the piece number, so look at the sockets themselves.

WBC set	Drive	Pieces	Buy it when
Milwaukee metric ratchet set	3/8 inch	32	Your work is mostly metric
Milwaukee ratchet set	3/8 inch	28	You want a 3/8-inch ratchet kit; check its sizes against your work
Channellock SAE and metric socket set	3/8 inch	20	You turn both inch and metric fasteners and want one compact set
SAE and metric socket set, two drives	1/4 and 3/8 inch	63	You also want 1/4-inch drive for small fasteners in tight spots

If your jobs mix inch and metric, a mixed set saves buying two. If you need 1/2-inch drive too, that’s a separate set; drive size and fastener system are separate choices.

Six-point or 12-point

A six-point socket grips the flats of a hex nut and is the one to reach for on a tight or rusted fastener, because it’s less likely to round the corners. A 12-point socket fits hex and double-hex fasteners and gives you twice as many positions to slip it onto the fastener, which helps when the socket is hard to line up in a tight spot. For breaking things loose, six-point first.

Deep or shallow

A deep socket has room inside for a long bolt sticking past the nut, and it reaches nuts down in a recess. A shallow socket is shorter, so it fits where the ratchet and socket together have to squeeze between parts. Check that a set has the sizes you need in the depth you need; plenty of sets cover a size in one depth and not the other.

Using sockets on an impact driver

Only impact-rated sockets go on an impact driver or impact wrench, and the adapter has to be impact-rated too. An ordinary hand socket isn’t made for that hammering. A socket and adapter that fit together only prove the connection, not that they’ll survive the hammering.

Hex-bit sockets for Allen-head bolts

For internal hex fasteners, the Allen-head bolts on equipment, furniture and machinery, a regular socket won’t work; it fits over the outside of a fastener. A hex-bit socket has an Allen key built into it, so your ratchet can turn a hex bolt with real leverage. WBC carries Channellock 3/8-inch drive hex-bit sockets in 1/2-inch and in 4, 6 and 10 mm. Match the bit to the fastener exactly; a loose fit strips the hex.

The Pick

For mostly metric work, buy the Milwaukee 32-piece metric ratchet set; for a mix of inch and metric, the Channellock 20-piece SAE and metric set; for 1/4-inch drive too, the 63-piece two-drive set. Add Channellock hex-bit sockets for Allen-head bolts and the 3/8-to-1/4 adapter to run small sockets off your ratchet. For an impact tool, use only impact-rated sockets and adapters.

Frequently Asked Questions

What does 3/8-inch drive mean on a socket set?

It’s the size of the square connection between socket and ratchet. The socket’s SAE or metric size is a separate number that tells you which fastener it fits. A suitable adapter lets a different-size ratchet drive the socket, but it doesn’t change the socket’s strength.

Six-point or 12-point sockets?

Six-point for tight or rusted fasteners, because they grip the flats and are less likely to round the corners. Twelve-point fits hex and double-hex fasteners and gives more positions to slip it onto a fastener that’s hard to line up.

Can I use a 3/8-inch socket set with an impact driver?

Only if the sockets and adapter are rated for impact use. Ordinary hand sockets aren’t made for the hammering, and an adapter that fits doesn’t make a hand socket impact-rated.

What is a hex-bit socket for?

Turning internal hex (Allen-head) bolts with a ratchet. It’s an Allen key mounted in a socket, so you get ratchet leverage on a fastener a regular socket can’t grip. Match the size exactly to avoid stripping the hex.