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3/8 inch socket set buying guide

Updated: 22 October 2026

You are looking at a 39-piece box, or a black socket, and you still cannot tell whether it will sit on the 13 mm nut on the mower. A 3/8 inch socket set buying guide starts with the square, not the number on the lid. The square on the ratchet and the hole in the socket both have to be 3/8 inch. The number stamped on the wall is the nut. Our [3/8 inch socket set comparison](/hub/hand-tools/3-8-inch-socket-set) lists eight amazon.co.uk sets, with prices from 19 October 2026. Which role suits you is on the [best 3/8 inch socket set](/hub/hand-tools/3-8-inch-socket-set/sub/3-8-inch-socket-set-best) page. A qualifying purchase can earn a commission at no extra cost to you.

You are looking at a 39-piece box, or a black socket, and you still cannot tell whether it will sit on the 13 mm nut on the mower. A 3/8 inch socket set buying guide starts with the square, not the number on the lid.

Our top picks

Draper Draper Expert 18-piece 3/8 inch socket set

Best overall

Draper Draper Expert 18-piece 3/8 inch socket set
8.9/10about £26.47
View offer
WORKPRO WORKPRO 39-piece 1/4 and 3/8 inch socket set

Best value

WORKPRO WORKPRO 39-piece 1/4 and 3/8 inch socket set
8.3/10about £19.99
View offer
Silverline Silverline 13-piece 3/8 inch socket rail

Rank 3

Silverline Silverline 13-piece 3/8 inch socket rail
6.6/10about £10.95
View offer
On this page
  1. 1.What the 3/8 inch square actually is
  2. 2.6-point, 12-point, depth, and metric or AF
  3. 3.Steel, finish, and what the case is doing
  4. 4.What to count in the box

What the 3/8 inch square actually is

The 3/8 inch figure is the drive square, about 10 mm across, not the bolt size. RS Components puts it the same way: drive size is the imperial square, and the stamped size is the nut. A 13 mm socket exists on 1/4 inch, 3/8 inch and 1/2 inch drive, so the wall stamp does not tell you which ratchet it belongs to. Wonkee Donkee’s tables put 3/8 inch metric heads at roughly 5.5 mm to 22 mm, so you still count the sockets that are actually 3/8 inch.

6-point, 12-point, depth, and metric or AF

On a rusty hex nut, a 6-point socket is the safer default because it bears on the flats. A 12-point socket seats faster and puts more load on the corners. Use 12-point when the fastener itself is 12-point. Point style does not permit impact-wrench use. Depth is reach, not strength. A shallow socket needs room above the nut. A deep socket clears a stud. TecoTek states semi-deep sockets from 7 mm to 19 mm. If the listing is silent on depth, you do not know the reach. Metric is usual on a modern UK car, bike or mower. AF, or imperial SAE, still turns up on older hardware.
Draper Draper Expert 18-piece 3/8 inch socket set

Testsieger

Draper Draper Expert 18-piece 3/8 inch socket set
8.9/10about £26.47
View offer

Steel, finish, and what the case is doing

Chrome vanadium is the usual hand-socket alloy. Chrome molybdenum is the usual impact alloy, because it is more likely to deform than to shatter. Cromwell’s note is direct: chrome hand sockets stay off an impact wrench. Black phosphate is a finish. Wonkee Donkee warns that a black socket can still be chrome vanadium. In this sample the CASOMAN title says impact and the steel line says chrome vanadium (50BV30). Whether a socket may go on the wrench is the 3/8 inch impact socket page. Draper cites DIN 3122 and ISO 3315 on the ratchet. They are hand-wrench standards, not an impact certificate.

What to count in the box

Count 3/8 inch sockets, not the piece total. The WORKPRO 39-piece listing, at about £19.99, mixes 1/4 inch and 3/8 inch, and only six sockets are 3/8 inch. The Silverline rail, at about £10.95, is 13 metric 6-point sockets, with 7 mm and 18 mm absent. The Draper Expert set, at about £26.47, includes a 72-tooth ratchet, and a content line checked on 20 October 2026 skips 7 mm, 20 mm and 23 mm. The WORKPRO 14-piece set stops at 17 mm. Seating the square is on how to use a 3/8 inch socket set.

Common questions

Is the number on the socket the drive size or the nut size?
The number on the wall is the nut, such as 10 mm or 13 mm. The drive size is the square that enters the ratchet, and on this page that square is 3/8 inch. A 13 mm marking can appear on more than one drive, so you still match the square. If you buy by the wall stamp alone, you can end up with a socket that will not start on the handle you own.
Should a first 3/8 inch set be 6-point or 12-point?
For a first household set, 6-point is the safer default on a hex nut, because it bears on the flats. Choose 12-point when the fastener is 12-point or you need to seat the socket in a tighter swing. A 12-point socket on a rusty hex puts more load on the corners and rounds them more easily. Point count does not change the alloy, and it does not permit impact-wrench use.
When do you need a deep socket instead of a shallow one?
Use a shallow socket when there is clear room above the nut and the socket can sit fully on the flats. Use a deep socket when a stud or a long thread would stop a shallow well halfway. Semi-deep is the mid length for a gap that rejects a full deep socket. If the listing is silent on depth, you do not know which of those jobs the set can finish.
Why does a 39-piece set sometimes include only a handful of 3/8 inch sockets?
Because the piece count adds every item in the case: 1/4 inch sockets, bits, an extension, a spinner and the ratchet. The WORKPRO 39-piece listing in this sample states six 3/8 inch sockets. The rest of the count is the other drive and the accessories. Read the line that says how many sockets are 3/8 inch before you compare it with an 18-piece set that is 3/8 inch throughout.
Does chrome vanadium mean the set is for an impact wrench?
No. Chrome vanadium is the usual hand-socket alloy. Impact sockets are usually chrome molybdenum, because that alloy is more likely to bend than to shatter under a hammering wrench. A black finish does not change the steel. If the page says chrome vanadium, keep the set on a hand ratchet.
What is missing if the set is sockets on a rail and no ratchet?
The handle. A rail such as the Silverline 13-piece set is sockets only, so you need a 3/8 inch ratchet or torque wrench you already own. You also need to check the missing sizes. On that rail, 7 mm and 18 mm are not in the contents line, and the clips are stiff to unclip.

Related pages

3/8 vs 1/2 inch socket set

3/8 inch socket set

Best 3/8 inch socket set: compact kit, case, or rail

How to use a 3/8 inch socket set without rounding nuts

3/8 inch impact socket: read the steel, not the colour

Sources

Public UK sources from the research digest, last checked on 20 October 2026. Shelf prices and star lines are the amazon.co.uk figures in the product display for this comparison.

  1. HSE: PUWER overview (retrieved 20 October 2026)
  2. HSE: using the right type of PPE (retrieved 20 October 2026)
  3. Wonkee Donkee: what is an impact socket (retrieved 20 October 2026)
  4. Wonkee Donkee: what are sockets made of (retrieved 20 October 2026)
  5. Cromwell: sockets and socket sets (retrieved 20 October 2026)
  6. KS Tools 3/8 inch hexagon impact socket (retrieved 20 October 2026)
  7. PartsForMachines: mechanics and automotive socketry (retrieved 20 October 2026)
  8. Bradfords: socket sets (retrieved 20 October 2026)