Description
Look down the 1-9/16 in row of Snap-on’s open end charts and the J column is almost empty. The standard QJO range skips that size, so the Snap-on QJO50ARTH open end head stands alone there. It gives a J-shank body a thin 1-9/16 in jaw with a 60 ft-lb limit in CAT1500i.
Every 1-9/16 in head Snap-on offers
| Head | Type | Shank | Limit |
|---|---|---|---|
| QJO50ARTH | Thin open end | J (0.425 in) | 60 ft-lb |
| QYO50ARTH | Thin open end | Y (0.560 in) | 160 ft-lb |
| QYO50A | Standard open end | Y (0.560 in) | 160 ft-lb |
| QXO50A | Standard open end | X (0.735 in) | 240 ft-lb |
So on a J body, the QJO50ARTH is the only way to reach this size. On the other hand, a Y or X body opens up stronger heads for higher specs.
Sizing up the Snap-on QJO50ARTH open end head
- Opening: 1-9/16 in, which equals 39.69 mm.
- Shank: J (0.425 in).
- Working limit in CAT1500i: 60 ft-lb (roughly 81.3 N·m).
- Fastener center to retaining pin: 2.50 in, the QJO series spacing.
Its J thin neighbors are the QJO48ARTH at 1-1/2 in and the QJO52ARTH at 1-5/8 in. A 1/16 in step separates each of them, so a caliper check of the flats saves a wrong order.
Matching a J body to the 60 ft-lb limit
Most J bodies reach past what this head can take. For example, the QC2I75 adjustable runs 5-75 ft-lb. The QD2IN100A dual-range body reads 20-100 N·m, or 16.6-71.9 ft-lb. With any of them, keep the setting at or below 60 ft-lb while the QJO50ARTH sits on the tube. In addition, CAT1500i adds a footnote that ties some open end heads to the QC1P100 and QC1I200 bodies. Its marks do not survive in the catalog text, so ask Lost in HCM to confirm your pairing.
Jobs for the Snap-on QJO50ARTH open end head
For instance, a jam nut that locks a turnbuckle or a cylinder rod end often sits tight against a second nut. A socket cannot reach it there. The thin jaw of the QJO50ARTH slides in from the side. Then the J body stops the pull at a measured value. Because the opening converts to 39.69 mm, keep it for inch hardware rather than metric nuts.
Care for the QJO50ARTH jaws
A thin jaw gives access, but it also flexes more than a thick one. So seat both faces fully on the flats, then pull at an even pace to the signal. Snap-on warns against using its torque tools to break fasteners loose, so crack a stuck nut with a plain wrench first. Finally, test the jaw gap on a known nut from time to time.
Ordering the QJO50ARTH from Lost in HCM
SMK Vietnam lists the Snap-on QJO50ARTH open end head for its partner, and Lost in HCM supplies it and writes the quote. Tell the team your J body model and the torque value of the joint. Then ask Lost in HCM to quote the thin 1-9/16 in head. You can also browse torque wrench heads and adaptors, or contact SMK Vietnam with fit questions.
Common QJO50ARTH queries from J-body users
Does Snap-on make a standard J-shank head at 1-9/16 in?
No. The standard chart shows only the Y-shank QYO50A and the X-shank QXO50A at that size.
What suits a 1-9/16 in nut that needs 120 ft-lb?
Move to a Y body and the thin QYO50ARTH, which Snap-on rates at 160 ft-lb.
Will the QJO50ARTH lock into a Y-shank wrench?
No. Its J shank (0.425 in) fits J bodies only, so a Y wrench needs a Y head.
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