Description
Hangar crews and HVAC fitters meet the same problem on small lines: a tube nut buried behind clamps, with only a few degrees of swing. The Snap-on RTWH44JSL flare nut head fits an 11/16 in nut in that spot. Its open ring passes over the tube, and then the head ratchets back on the nut instead of coming off.
RTWH44JSL specification
- Opening: 11/16 in, 12-point, ratcheting.
- Shank: J (0.425 in).
- Pin-to-nut-center reach: 3.50 in, the RTWHJ figure.
- Standard: Boeing ST2599, according to Snap-on.
- Twin part: RTWH44YSL, the same opening on a Y shank.
11/16 in is not 17 mm
Many split air conditioners use 17 mm flare nuts, which look almost identical to 11/16 in. Yet 11/16 in equals 17.46 mm, so the RTWH44JSL would sit loose on a true 17 mm nut. That slack can round a soft brass corner. So keep the Snap-on RTWH44JSL flare nut head for true inch nuts. In addition, measure the nut, and ask Lost in HCM about Snap-on’s metric sizes, which come on special order.
Jobs that suit the Snap-on RTWH44JSL flare nut head
On inch hydraulic systems, the -4 O-ring face seal nut for 1/4 in tube often measures 11/16 in. Small fuel, oil and pneumatic unions on US-built engines and compressors fall here too. In addition, aircraft task cards often call for a calibrated wrench on fittings this size. Since makers differ, check each nut across flats first.
Ratchet or solid head at 11/16 in?
| Part | Style | Shank | Rating |
|---|---|---|---|
| RTWH44JSL | Ratcheting 12-point | J | Not listed |
| QYRX22A | Solid 12-point | Y | 92 ft-lb |
| QYRXS22A | Solid 6-point | Y | 92 ft-lb |
So choose the RTWH44JSL when a clean nut needs many short strokes. On the other hand, pick a solid Y head when the joint calls for a published limit.
Setting a J body with the longer reach
The RTWH44JSL sits 3.50 in from the pin, while standard J heads sit at 2.50 in. That extra inch changes what a click scale means. For this reason, a CTECH1J240A ControlTech body is the simplest match, because it stores a head-length factor. With a QC2I75 or a QD2IN100A, ask Lost in HCM or Snap-on how to correct the value.
Lost in HCM quotes for the Snap-on RTWH44JSL flare nut head
Lost in HCM supplies the RTWH44JSL and prices each request, and SMK Vietnam shows it as a partner product. Send your body model and the fitting spec. After that, ask Lost in HCM for an RTWH44JSL quotation. Related heads live under torque wrench heads and adaptors, and you can always contact SMK Vietnam.
RTWH44JSL questions answered
Will the RTWH44JSL grip a 17 mm nut?
Not well. Its 11/16 in opening is about 0.46 mm wider than 17 mm, so it can slip.
Which 11/16 in Snap-on head has a printed rating?
The solid Y heads QYRX22A and QYRXS22A, both at 92 ft-lb. The ratcheting head has none in the table.
Is the RTWH44JSL suitable for aircraft lines?
Snap-on states the line meets Boeing ST2599. Still, check your own tool list before you order.
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