Small imperial fasteners run in sixteenths and thirty-seconds of an inch, and the increments are fine enough that guessing does not work. This is the complete list of 9 six-point SAE regular sockets in 1/4 inch drive, with the Teng part number for each.
Why the small imperial sizes are so close together
At the top of the range, imperial sizes step in sixteenths — an obvious difference you can see across a bench. Down here they step in thirty-seconds, so 7/32, 1/4 and 9/32 sit within a thirty-second of each other and look identical in a tray. The practical consequence is that small SAE sockets have to be read rather than recognised, and a set that keeps them in size order in a rail is worth considerably more than one that does not.
Six point is not optional at this size
On a 1/4 inch hex there is very little corner to lose. A twelve-point socket that is fractionally loose will round a small imperial head in one pull, and unlike a larger fastener there is no second attempt with a bigger tool — the head is simply gone and the fastener has to be drilled. The extra thirty degrees of ratchet swing a twelve-point buys is not worth that on small hardware.
All 9 SAE sizes
| Size | Decimal inch | Millimetres | Teng part number | EAN |
|---|---|---|---|---|
| 3/16 in | 0.1875 | 4.76 | M140106-C | 5020385132221 |
| 7/32 in | 0.2188 | 5.56 | M140107-C | 5020385132238 |
| 1/4 in | 0.2500 | 6.35 | M140108-C | 5020385132245 |
| 9/32 in | 0.2813 | 7.14 | M140109-C | 5020385132252 |
| 5/16 in | 0.3125 | 7.94 | M140110-C | 5020385132269 |
| 11/32 in | 0.3438 | 8.73 | M140111-C | 5020385132276 |
| 3/8 in | 0.3750 | 9.52 | M140112-C | 5020385132283 |
| 7/16 in | 0.4375 | 11.11 | M140114-C | 5020385132290 |
| 1/2 in | 0.5000 | 12.70 | M140116-C | 5020385132306 |
Where this list comes from
Every row is read from the live Teng Tools USA catalogue on the day this page was generated — product record, part number and size taken from the record itself, never transcribed from a printed catalogue or inferred from a pattern. Sizes are as stamped, in fractions of an inch across the flats of the fastener. A size that has been discontinued disappears from this list rather than lingering as a part number you cannot order, which is the failure mode of every static spec sheet. AF means "across flats": the distance between two opposite faces of the hex, which is what the socket actually grips. Millimetre equivalents are exact conversions at 25.4 mm to the inch and are provided for cross-referencing only.
Mixed assemblies
Small metric and small imperial sizes overlap almost exactly in this range, which is where most cross-standard damage happens. A 5/16 inch socket is 7.94 mm and will go onto an 8 mm nut feeling nearly right; 11/32 is 8.73 mm and will do the same to a 9 mm. Neither pairing survives a tight fastener. If a socket goes on with any perceptible movement, it is from the wrong range, and the millimetre column below is the fastest way to check that at the bench.
The range is in sockets and accessories; full ranges in socket sets.