A wobble bar lets the socket sit at a small angle to the bar, which is usually all that is needed to reach a fastener that is not quite square on. This is the complete list of 3 lengths in 3/8 inch drive.
How the wobble actually works
The drive end is machined with relieved corners so the socket can tilt a few degrees in any direction while the square still drives it. That is a much smaller allowance than a universal joint gives, and the smallness is the point: the bar stays essentially in line, so it keeps its stiffness and the feel travelling back up it, while the socket accommodates the misalignment at the fastener. It is the difference between reaching a bolt and reaching it with any idea what you are doing to it.
The angle limit is real
Pushed beyond the few degrees it was cut for, the square stops bearing on the flats of the socket and starts bearing on the relieved corners. That concentrates the entire load on the machined-away part of the drive, which is where a wobble bar breaks. If the socket needs more angle than the bar gives willingly, the honest answer is a universal joint — forcing a wobble bar to do a universal joint’s work destroys the bar and often the socket with it.
All 3 lengths
| Length | Length (in) | Teng part number | EAN |
|---|---|---|---|
| 75 mm | 2.95 | M380020W-C | 5020385131286 |
| 150 mm | 5.91 | M380021W-C | 5020385131293 |
| 255 mm | 10.04 | M380022W-C | 5020385131309 |
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. Lengths are as recorded on the product; the inch column is an exact conversion, rounded for display. 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.
Wobble bars and torque settings
Because a wobble bar puts the socket at an angle, the torque reaching the fastener is fractionally lower than the torque applied at the wrench — the cosine of the angle, which at five degrees is under half a per cent and safely ignorable, and at twenty degrees is six per cent and not. For any fastener with a specified torque figure, straighten the assembly before the final tightening pass even if the wobble was needed to start it.
Bars are in sockets and accessories; torque wrenches are in torque equipment.