Williams SNPBCF20 3/8 Dr Crowft Flarenut 5/8

The Williams SNPBCF20 is a 3/8 inch drive crowfoot flare nut wrench, 5/8 inch.

A crowfoot on a torque wrench changes the torque, and that is the single most important thing about this tool — and it is almost never printed anywhere.

Here is why. A torque wrench is calibrated for force applied at a specific distance from the drive. A crowfoot moves the fastener out beyond the drive square, lengthening the effective lever arm. A wrench set to 30 ft-lb with a crowfoot fitted in line delivers more than 30 ft-lb to the fastener — and the longer the crowfoot, the greater the error.

There are two answers. Mount the crowfoot at ninety degrees to the wrench handle, which leaves the effective length unchanged and the setting correct. Or calculate the correction: the setting must be reduced in proportion to the added length.

Fitting a crowfoot in line and trusting the click is how torque-critical fittings get over-tightened, and on a brake or fuel line that matters.

The flare nut profile is the other specification. It is a box wrench with a slot: it slides over the tube and grips five of the six flats, where an open-end wrench grips two and rounds the soft nut.

Applications include brake, fuel, and hydraulic lines.

Brand

Williams

SKU

SNPBCF20

Category

Hand Tools

Weight

0.13 lbs

Dimensions

2.50 x 0.75 x 0.75

Price

$24.95

Availability

Call for pricing

Rating

3.67 / 5.0