Deep SAE sockets reach nuts that sit down a protruding stud, sized in fractions of an inch across the flats. This is the complete list of 9 in 3/8 inch drive, with the Teng part number for each.
Depth, and what it is really buying you
The useful measurement of a deep socket is not its overall length but how far a stud can protrude through the nut before the socket stops seating. On imperial hardware that clearance gets used up quickly: coarse UNC threads on long studs are common in exactly the applications — exhaust flanges, leaf-spring U-bolts, generator and pump mounts — where a nut has been run down over an inch of exposed thread. A regular socket in the right size will touch the stud and sit proud, and every turn after that is being taken on the top corner of the hex.
Deep sockets on an extension
A deep socket already moves the ratchet head away from the fastener, and adding an extension bar compounds it. The stack behaves like a torsion bar: it twists slightly before the fastener moves, so the ratchet is loaded before anything turns, and it wants to wander off axis. Keep the shortest combination that reaches, support the drive end with your free hand, and pull rather than push where you can — a slipped push puts your knuckles into whatever is behind the fastener.
All 9 deep SAE sizes
| Size | Decimal inch | Millimetres | Teng part number | EAN |
|---|---|---|---|---|
| 3/8 in | 0.3750 | 9.52 | M380212-C | 5020385132498 |
| 7/16 in | 0.4375 | 11.11 | M380214-C | 5020385132504 |
| 1/2 in | 0.5000 | 12.70 | M380216-C | 5020385132511 |
| 9/16 in | 0.5625 | 14.29 | M380218-C | 5020385132528 |
| 5/8 in | 0.6250 | 15.88 | M380220-C | 5020385132795 |
| 11/16 in | 0.6875 | 17.46 | M380222-C | 5020385132535 |
| 3/4 in | 0.7500 | 19.05 | M380224-C | 5020385132542 |
| 13/16 in | 0.8125 | 20.64 | M380226-C | 5020385133280 |
| 7/8 in | 0.8750 | 22.22 | M380228-C | 5020385133297 |
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. Deep and regular sockets in the same nominal size are different part numbers and appear on separate lists. 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.
The rounded-nut point of no return
Once the corners of a nut have gone, a correctly sized deep socket will not grip either, and going up a size to get purchase removes what is left of the flats. That is the moment to change tools rather than technique: a reverse-spiral extractor socket bites into the damaged hex instead of surrounding it. Applying heat first often makes the extraction easier, but it also anneals the fastener, so decide whether the nut is being saved or sacrificed before the torch comes out.
The range is in sockets and accessories; impact-rated deep sockets are in impact sockets.