On half-inch drive a wobble bar reaches fasteners set slightly off the line of approach — suspension bolts behind a hub, manifold nuts under a heat shield. This is the complete list of 3 lengths, with part numbers.
Small angle, high torque, real consequences
A wobble end is machined away at the corners of the square so the socket can tilt. That machining removes material from the part of the drive that carries the load, so a wobble bar is inherently a little weaker than a plain bar of the same size — and half-inch drive is where the torque is high enough for that to matter. Use the wobble to get the socket onto the fastener, then bring the assembly as straight as the space allows before applying real force.
Wobble, universal joint or a different approach
A wobble allows a few degrees, a universal joint allows a great many, and each gives up something. Below about ten degrees the wobble is clearly better: stiffer, more controlled, and it keeps the feedback that tells you what the fastener is doing. Beyond that the wobble is being abused and the joint is the correct tool. Beyond about thirty degrees even a joint transmits torque unevenly enough to be worth avoiding, and it is time to reconsider the access rather than the adaptor.
All 3 lengths
| Length | Length (in) | Teng part number | EAN |
|---|---|---|---|
| 75 mm | 2.95 | M120020W-C | 5020385131255 |
| 150 mm | 5.91 | M120021W-C | 5020385131262 |
| 255 mm | 10.04 | M120022W-C | 5020385131279 |
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 read from the product record; the inch column is an exact conversion at 25.4 mm to the inch, 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.
Never on an impact wrench
A chrome wobble bar has the least material of any bar at exactly the point an impact wrench hammers hardest, and the relieved corners concentrate that hammering into a small area. It is the component in a half-inch stack most likely to fail on a rattle gun, and it fails by breaking rather than deforming. Impact work needs impact-rated tooling throughout; there is no version of this where a chrome wobble bar is the right choice on a powered gun.
Chrome bars are in sockets and accessories; impact-rated tooling is in impact sockets.