Description
M20 bolts tie down motors, crane rails and machine bases, and ISO gives them a 30 mm hex. On many of those joints the nut sits beside a web or gusset, so a socket cannot square up. The Snap-on QXXM30A box end head reaches that nut from the side. Its closed 12-point ring rides on an X shank, the mid-heavy size in the Snap-on range.
Snap-on QXXM30A box end head dimensions
- Opening: 30 mm, 12-point, closed ring.
- Shank: X (0.735 in).
- Outside diameter: 44 mm. Head depth: 19 mm.
- Pin to fastener center: 4.50 in, shared by the QXXM series.
- Finish: industrial (partner data).
X body ceilings and an M20 spec
Before you order, compare your M20 value with the X bodies Snap-on prints.
| X body | Range | Length |
|---|---|---|
| QD3IN350A | 59-251 ft-lb (70-350 N·m) | 23 in |
| QC4P300 preset | 60-300 ft-lb | 27 in |
| CTECH3X250A | 12.5-250 ft-lb | 24.1 in |
If the spec sits inside one of those ranges, the Snap-on QXXM30A box end head is a sound pick. However, high-grade M20 joints can call for more. In that case, step up to a Z body and the QZXM30ADP.
The rating we could not settle
Snap-on’s UK brochure and the partner listing print different maximum working torques for the QXXM30A. So we leave both off this page. Lost in HCM confirms the figure with the quote, and the wrench stays at or below it.
Gusset room and a steady pull
The 44 mm ring of the QXXM30A needs about 22 mm from the bolt center to the nearest web. Then seat the ring fully over the hex, because a half-seated ring can tip under load. Also pull at a slow, even rate and stop at the signal. Finally, free any seized nut with another tool, since Snap-on warns against breaking fasteners loose with a torque wrench.
Other 30 mm rings in the range
Beside the QXXM30A, the brochure lists a QYXM30A for Y bodies and a QZXM30A for Z bodies at the same width and depth. So one plant can match the shank to each M20 spec while the nut size stays the same.
Supply route for the Snap-on QXXM30A box end head
SMK Vietnam features this head for its partner Lost in HCM, which supplies it and writes each quote. List your X body, the bolt grade and the M20 value, then send the request to Lost in HCM. Other 30 mm rings sit under torque wrench heads and adaptors, and you can contact SMK Vietnam about fit.
QXXM30A questions from M20 users
Does the QXXM30A fit DIN M20 nuts?
Yes. DIN 934 and ISO 4032 both give M20 a 30 mm hex. Even so, measure coated parts first.
When should I move to the Z ring?
Move up when the spec passes what your X body reads. The QD3IN350A stops at 251 ft-lb, while the QC4P300 stops at 300 ft-lb.
Will the 44 mm ring clear a gusset?
It needs about 22 mm from the bolt center, so measure the gap to the gusset before you order.
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