Type “F” Clamps for Plumbing Applications: Key Specifications and Best Practices

The SAE J1670-2022 standard defines the complete dimensional and general specifications for Type F worm drive hose clamps used in plumbing. This stabilized standard covers materials, performance testing, and installation guidance to ensure reliable and repeatable clamping performance.

Dimensional and Material Specifications

Type F clamps use a worm drive mechanism with a tangentially mounted buttress-thread screw enclosed in a housing fastened to the band. Rotating the screw clockwise reduces the clamp diameter; counterclockwise opens it. All clamps must be fabricated from 200 or 300 series austenitic stainless steel for corrosion resistance. Table 1 lists key dimensions for common sizes; the full standard covers sizes 06 through 104.

Size No.	Open Diameter (mm)	Open Diameter (in)	Closed Diameter (mm)	Closed Diameter (in)	Radius Over Screw (mm)	Radius Over Screw (in)
06	19.8	0.78	11.2	0.44	29.7	1.17
08	23.1	0.91	12.7	0.50	30.9	1.22
10	26.9	1.06	14.2	0.56	32.0	1.26
12	31.7	1.25	17.5	0.69	33.5	1.32
16	38.1	1.50	20.6	0.81	36.1	1.42
20	44.4	1.75	20.6	0.81	38.6	1.52

Note: Clamps must be capable of closing smaller than the listed closed diameters while meeting performance requirements. For sizes greater than 104, contact the manufacturer.

Performance Testing and Installation Requirements

The standard defines several tests to verify clamp performance:

• Clamping Diameter Range – Clamps must assemble over and close tight on mandrels equal to the open and closed diameters. All threads must be fully engaged when testing maximum and minimum open diameter.
• Free Running Torque – Measured over four complete revolutions in the free state, excluding break-away effects.
• Durability Torque – Clamps are tightened to 5.6 N·m (50 lb-in) on a steel mandrel without thread or housing deformation.
• Ductility Test – The band is bent 180° around a 4.77 mm (0.188 in) mandrel at the perforated portion, then restraightened, with no cracking or failure allowed.

Installation Torque: The manufacturer’s recommended installation torque for all Type F clamps is 3.44 N·m (30 lb-in). Users should establish the appropriate torque for their specific application. Assembly Tools: Stall torque type power tools are recommended; clutch type or impact tools should not be used.

Frequently Asked Questions

Q1: What materials are used for Type F clamps?
A1: Bands, screws, and housings must be fabricated from 200 or 300 series austenitic stainless steel for corrosion resistance.

Q2: What is the recommended installation torque for Type F clamps?
A2: The manufacturer’s recommended torque is 3.44 N·m (30 lb-in) for all sizes and materials. Users should determine the optimal torque for their application.

Q3: Can impact or clutch power tools be used for installation?
A3: No. Only stall torque type power tools are advised. Clutch or impact tools can cause overtightening and damage to the clamp threads or housing.

Q4: What does the ductility test involve?
A4: The band is bent 180° around a 4.77 mm diameter mandrel at the perforated area and then restraightened. It must not crack or show any signs of failure.