Description
A 29 mm hex sits between the 27 mm and 30 mm sizes, and some machine and hydraulic parts use it. The Snap-on QXXM29A box end head grips that hex with a 12-point ring on an X-shank torque body. As a result, the load spreads over every corner instead of two flats.
QXXM29A measurements
| Opening | 29 mm, 12-point box end |
|---|---|
| Shank | X (0.735 in) |
| O.D. | 42 mm |
| Head depth | 18 mm |
| Fastener center to retaining pin | 4.50 in (QXXM series) |
The source listing and Snap-on’s UK torque brochure give different torque limits for the QXXM29A. So we omit the figure, and Lost in HCM confirms it.
Ring versus jaw at 29 mm
Snap-on’s 29 mm open-end heads measure 58 mm across and 12 mm deep. The QXXM29A ring, by contrast, measures 42 mm across and 18 mm deep. Therefore the ring fits a narrow gap between two bolts, while the jaw fits a low gap under a lip. However, the ring must drop over the nut. So a pipe or a long stud through the joint rules it out.
X bodies for the Snap-on QXXM29A box end head
The QD3IN350A dual-range body reads 59 to 251 ft-lb and takes X heads. For a fixed value, the QC4P300 preset covers 60 to 300 ft-lb. Because the QXXM29A keeps the 4.50 in X spacing, Snap-on says the QD body needs no adjustment calculation. Still, confirm the head rating before you set a preset.
Y, X or Z at 29 mm
Snap-on’s brochure lists a 29 mm ring for three shanks: the QYXM29A, the QXXM29A and the QZXM29A. There is no J version at this size. So pick the head that matches the body you own. For lighter work on a Y station, the QYXM29A is shorter to swing. For heavier joints, a Z ring fits the largest body.
Caring for the Snap-on QXXM29A box end head
A worn 12-point ring hides its wear inside the bore. So test it on a new 29 mm nut now and then, and replace it if it rocks. Also clean the bore with a brush, since packed dirt lifts the ring off the nut.
Quote for the QXXM29A
Lost in HCM supplies this head and writes each quote, while SMK Vietnam lists it as a partner product. Request a QXXM29A quote from Lost in HCM and name your X body and torque target. Other jaws and rings sit under torque wrench heads and adaptors, and you can also contact SMK Vietnam.
Common QXXM29A questions
Is the QXXM29A narrower than a 29 mm open-end head?
Yes. It measures 42 mm across against 58 mm, but it sits 6 mm deeper.
Will the QXXM29A fit a 29 mm tube nut?
Only if no tube passes through the nut. Otherwise, use an open-end or flare nut head.
What limit should I set on the QXXM29A?
Use the value Lost in HCM confirms. Snap-on sources disagree, so do not guess.
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