How to Install Helical Inserts
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About Helical Insert Length
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Stainless Steel Helical Inserts
Also known as Heli-Coil inserts, these inserts have coils that expand once installed to securely anchor the insert. All have a prong for ease of installation. An installation tool grips the prong and reduces the coil diameter, enabling the insert to fit in tapped holes. Remove the prong to insert the screw. Installation requires a drill bit, a helical insert tap, an installation tool, and a prong break-off tool.
For technical drawings and 3-D models, click on a part number.
Inserts | Through-Hole Taps | Closed-End Hole Taps | Installation Tools | Prong Break-Off Tools | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Thread Size  | Installed Lg. | Drill Bit Size | For Max. Hole Dia. | Specifications Met | Pkg. Qty. | Pkg. | Each | Each | Each | Each | |||||
18-8 Stainless Steel—Right-Hand Threaded | |||||||||||||||
| 1/4"-20 | 1/4" | H | 0.266" | MS122-081 | 10 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 | 000000000 | 0000000 | 000000000 | 0000000 |
| 1/4"-20 | 3/8" | H | 0.266" | MS122-121 | 10 | 000000000 | 0000 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 |
| 1/4"-20 | 1/2" | H | 0.266" | MS122-161 | 10 | 000000000 | 0000 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 |
| 1/4"-20 | 5/8" | H | 0.266" | MS122-201 | 10 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 |
| 1/4"-20 | 3/4" | H | 0.266" | MS122-241 | 10 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 |
18-8 Stainless Steel—Left-Hand Threaded | |||||||||||||||
| 1/4"-20 | 3/8" | H | 0.266" | __ | 1 | 000000000 | 0000 | 000000000 | 00000 | 000000 | 00 | 000000000 | 00000 | 000000000 | 000000 |
Stainless Steel Helical Inserts for Particle-Free Environments
Made of Nitronic 60 stainless steel, these inserts prevent the screw from binding or sticking without any coating or lubricant that could contaminate particle-free environments. Also known as Heli-Coil inserts, they have coils that expand once installed to securely anchor the insert. All have a prong for ease of installation. An installation tool grips the prong and reduces the coil diameter, enabling the insert to fit in tapped holes. Remove the prong to insert the screw. Installation requires a drill bit, a helical insert tap, an installation tool, and a prong break-off tool.
For technical drawings and 3-D models, click on a part number.
Inserts | Through-Hole Taps | Closed-End Hole Taps | Installation Tools | Prong Break-Off Tools | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Thread Size | Installed Lg. | Drill Bit Size | For Max. Hole Dia. | Pkg. Qty. | Pkg. | Each | Each | Each | Each | |||||
Nitronic 60 Stainless Steel | ||||||||||||||
| 1/4"-20 | 1/4" | H | 0.266" | 5 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 | 000000000 | 0000000 | 000000000 | 0000000 |
| 1/4"-20 | 3/8" | H | 0.266" | 5 | 000000000 | 0000 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 |
| 1/4"-20 | 1/2" | H | 0.266" | 5 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 |
Lubricated Stainless Steel Helical Inserts
A dry film keeps the screw from sticking or binding in these inserts during installation. Also known as Heli-Coil inserts, they have coils that expand once installed to securely anchor the insert. All have a prong for ease of installation. An installation tool grips the prong and reduces the coil diameter, enabling the insert to fit in tapped holes. Remove the prong to insert the screw. Installation requires a drill bit, a helical insert tap, an installation tool, and a prong break-off tool.
For technical drawings and 3-D models, click on a part number.
Inserts | Through-Hole Taps | Closed-End Hole Taps | Installation Tools | Prong Break-Off Tools | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Thread Size | Installed Lg. | Drill Bit Size | For Max. Hole Dia. | Specifications Met | Pkg. Qty. | Pkg. | Each | Each | Each | Each | |||||
18-8 Stainless Steel | |||||||||||||||
| 1/4"-20 | 1/4" | H | 0.266" | MIL-I-8846, MS122-081 | 1 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 | 000000000 | 0000000 | 000000000 | 0000000 |
| 1/4"-20 | 3/8" | H | 0.266" | MIL-I-8846, MS122-121 | 1 | 000000000 | 0000 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 |
| 1/4"-20 | 1/2" | H | 0.266" | MIL-I-8846, MS122-161 | 1 | 000000000 | 0000 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 |
Lubricated Stainless Steel Helical Inserts for Dissimilar Metals
Eliminating the need for primer, these inserts are coated to resist corrosion when installed in different materials. They also prevent the screw from sticking or binding in the insert during installation. Also known as Heli-Coil inserts, they have coils that expand once installed to securely anchor the insert. All have a prong for ease of installation. An installation tool grips the prong and reduces the coil diameter, enabling the insert to fit in tapped holes. Remove the prong to insert the screw. Installation requires a drill bit, a helical insert tap, an installation tool, and a prong break-off tool.
For technical drawings and 3-D models, click on a part number.
Inserts | Through-Hole Taps | Closed-End Hole Taps | Installation Tools | Prong Break-Off Tools | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Thread Size | Installed Lg. | Drill Bit Size | For Max. Hole Dia. | Pkg. Qty. | Pkg. | Each | Each | Each | Each | |||||
18-8 Stainless Steel | ||||||||||||||
| 1/4"-20 | 1/4" | H | 0.266" | 1 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 | 000000000 | 0000000 | 000000000 | 0000000 |
| 1/4"-20 | 3/8" | H | 0.266" | 1 | 000000000 | 0000 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 |
| 1/4"-20 | 1/2" | H | 0.266" | 1 | 000000000 | 0000 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 |
Nickel Alloy Helical Inserts
Made of nickel alloy, these inserts are more resistant to acids and salt water than stainless steel inserts. Also known as Heli-Coil inserts, they have coils that expand once installed to securely anchor the insert. All have a prong for ease of installation. An installation tool grips the prong and reduces the coil diameter, enabling the insert to fit in tapped holes. Remove the prong to insert the screw. Installation requires a drill bit, a helical insert tap, an installation tool, and a prong break-off tool.
For technical drawings and 3-D models, click on a part number.
Inserts | Through-Hole Taps | Closed-End Hole Taps | Installation Tools | Prong Break-Off Tools | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Thread Size | Installed Lg. | Drill Bit Size | For Max. Hole Dia. | Pkg. Qty. | Pkg. | Each | Each | Each | Each | |||||
Nickel Alloy | ||||||||||||||
| 1/4"-20 | 1/4" | H | 0.266" | 1 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 | 000000000 | 0000000 | 000000000 | 0000000 |
| 1/4"-20 | 3/8" | H | 0.266" | 1 | 000000000 | 0000 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 |
Titanium Helical Inserts
These inserts have a high strength-to-weight ratio and resist acids and salt water better than nickel alloy and stainless steel inserts. Also known as Heli-Coil inserts, they have coils that expand once installed to securely anchor the insert. All have a prong for ease of installation. An installation tool grips the prong and reduces the coil diameter, enabling the insert to fit in tapped holes. Remove the prong to insert the screw. Installation requires a drill bit, a helical insert tap, an installation tool, and a prong break-off tool.
For technical drawings and 3-D models, click on a part number.
Inserts | Through-Hole Taps | Closed-End Hole Taps | Installation Tools | Prong Break-Off Tools | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Thread Size | Installed Lg. | Drill Bit Size | For Max. Hole Dia. | Pkg. Qty. | Pkg. | Each | Each | Each | Each | |||||
Titanium | ||||||||||||||
| 1/4"-20 | 1/4" | H | 0.266" | 1 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 | 000000000 | 0000000 | 000000000 | 0000000 |
| 1/4"-20 | 3/8" | H | 0.266" | 1 | 000000000 | 0000 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 |
| 1/4"-20 | 1/2" | H | 0.266" | 1 | 000000000 | 0000 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 |
Stainless Steel Screw-Locking Helical Inserts
A distorted thread grips the screw to resist loosening. Also known as Heli-Coil inserts, these inserts have coils that expand once installed to securely anchor the insert. All have a prong for ease of installation. An installation tool grips the prong and reduces the coil diameter, enabling the insert to fit in tapped holes. Remove the prong to insert the screw. Installation requires a drill bit, a helical insert tap, an installation tool, and a prong break-off tool.
For technical drawings and 3-D models, click on a part number.
Inserts | Through-Hole Taps | Closed-End Hole Taps | Installation Tools | Prong Break-Off Tools | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Thread Size | Installed Lg. | Drill Bit Size | For Max. Hole Dia. | Specifications Met | Pkg. Qty. | Pkg. | Each | Each | Each | Each | |||||
18-8 Stainless Steel | |||||||||||||||
| 1/4"-20 | 1/4" | H | 0.266" | MS21209C4-10, NASM21209 | 10 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 | 000000000 | 0000000 | 000000000 | 0000000 |
| 1/4"-20 | 3/8" | H | 0.266" | MS21209C4-15, NASM21209 | 10 | 000000000 | 0000 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 |
| 1/4"-20 | 1/2" | H | 0.266" | MS21209C4-20, NASM21209 | 10 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 |
| 1/4"-20 | 5/8" | H | 0.266" | MS21209C4-25, NASM21209 | 1 | 000000000 | 0000 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 |
| 1/4"-20 | 3/4" | H | 0.266" | MS21209C4-30, NASM21209 | 1 | 000000000 | 0000 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 |
Lubricated Stainless Steel Screw-Locking Helical Inserts
A dry film keeps the screw from sticking or binding in these inserts during installation, yet a distorted thread grips the screw to resist loosening. Also known as Heli-Coil inserts, they have coils that expand once installed to securely anchor the insert. All have a prong for ease of installation. An installation tool grips the prong and reduces the coil diameter, enabling the insert to fit in tapped holes. Remove the prong to insert the screw. Installation requires a drill bit, a helical insert tap, an installation tool, and a prong break-off tool.
For technical drawings and 3-D models, click on a part number.
Inserts | Through-Hole Taps | Closed-End Hole Taps | Installation Tools | Prong Break-Off Tools | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Thread Size | Installed Lg. | Drill Bit Size | For Max. Hole Dia. | Specifications Met | Pkg. Qty. | Pkg. | Each | Each | Each | Each | |||||
18-8 Stainless Steel | |||||||||||||||
| 1/4"-20 | 3/8" | H | 0.266" | MS21209C4-15L, NASM21209 | 5 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 | 000000000 | 0000000 | 000000000 | 0000000 |
| 1/4"-20 | 1/2" | H | 0.266" | MS21209C4-20L, NASM21209 | 1 | 000000000 | 0000 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 |
Stainless Steel Screw-Locking Helical Inserts for Particle-Free Environments
Made of Nitronic 60 stainless steel, these inserts prevent the screw from binding or sticking without any coating or lubricant that could contaminate particle-free environments. Once the screw is installed, a distorted thread grips the screw to resist loosening. Also known as Heli-Coil inserts, they have coils that expand once installed to securely anchor the insert. All have a prong for ease of installation. An installation tool grips the prong and reduces the coil diameter, enabling the insert to fit in tapped holes. Remove the prong to insert the screw. Installation requires a drill bit, a helical insert tap, an installation tool, and a prong break-off tool.
For technical drawings and 3-D models, click on a part number.
Inserts | Through-Hole Taps | Closed-End Hole Taps | Installation Tools | Prong Break-Off Tools | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Thread Size | Installed Lg. | Drill Bit Size | For Max. Hole Dia. | Pkg. Qty. | Pkg. | Each | Each | Each | Each | |||||
Nitronic 60 Stainless Steel | ||||||||||||||
| 1/4"-20 | 1/4" | H | 0.266" | 5 | 000000000 | 000000 | 000000000 | 000000 | 000000000 | 000000 | 000000000 | 0000000 | 000000000 | 0000000 |
| 1/4"-20 | 3/8" | H | 0.266" | 5 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 |
| 1/4"-20 | 1/2" | H | 0.266" | 5 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 |
Stainless Steel Helical Inserts without Prong
Without a prong to break off and retrieve, these inserts are often used where debris could cause damage. Also known as Heli-Coil inserts, they have coils that expand once installed to securely anchor the insert. Installation requires a drill bit, a helical insert tap, and an installation tool.
For technical drawings and 3-D models, click on a part number.
Inserts | Through-Hole Taps | Closed-End Hole Taps | Installation Tools | Extraction Tools | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Thread Size | Installed Lg. | Drill Bit Size | For Max. Hole Dia. | Specifications Met | Pkg. Qty. | Pkg. | Each | Each | Each | Each | |||||
18-8 Stainless Steel | |||||||||||||||
| 1/4"-20 | 1/4" | H | 0.266" | NAS1130-4-10 | 10 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 | 000000000 | 0000000 | 000000000 | 0000000 |
| 1/4"-20 | 3/8" | H | 0.266" | NAS1130-4-15 | 10 | 000000000 | 0000 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 |
| 1/4"-20 | 1/2" | H | 0.266" | NAS1130-4-20 | 10 | 000000000 | 0000 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 |
| 1/4"-20 | 5/8" | 17/64" | 0.2656" | NAS1130-4-25 | 10 | 000000000 | 0000 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 |
| 1/4"-20 | 3/4" | 17/64" | 0.2656" | NAS1130-4-30 | 10 | 000000000 | 0000 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 |
Lubricated Stainless Steel Helical Inserts without Prong
A dry film keeps the screw from sticking or binding in these inserts during installation. Without a prong to break off and retrieve, they are often used where debris could cause damage. Also known as Heli-Coil inserts, they have coils that expand once installed to securely anchor the insert. Installation requires a drill bit, a helical insert tap, and an installation tool.
For technical drawings and 3-D models, click on a part number.
Inserts | Through-Hole Taps | Closed-End Hole Taps | Installation Tools | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Thread Size | Installed Lg. | Drill Bit Size | For Max. Hole Dia. | Pkg. Qty. | Pkg. | Each | Each | Each | ||||
18-8 Stainless Steel | ||||||||||||
| 1/4"-20 | 1/4" | H | 0.266" | 5 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 | 000000000 | 0000000 |
| 1/4"-20 | 3/8" | H | 0.266" | 5 | 000000000 | 0000 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 000000 |
| 1/4"-20 | 1/2" | H | 0.266" | 5 | 000000000 | 0000 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 000000 |
Screw-Locking Helical Inserts without Prong
A distorted thread grips the screw to resist loosening. Without a prong to break off and retrieve, these inserts are often used where debris could cause damage. Also known as Heli-Coil inserts, they have coils that expand once installed to securely anchor the insert. Installation requires a drill bit, a helical insert tap, and an installation tool.
For technical drawings and 3-D models, click on a part number.
Inserts | Through-Hole Taps | Closed-End Hole Taps | Installation Tools | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Thread Size | Installed Lg. | Drill Bit Size | For Max. Hole Dia. | Specifications Met | Pkg. Qty. | Pkg. | Each | Each | Each | ||||
18-8 Stainless Steel | |||||||||||||
| 1/4"-20 | 1/4" | H | 0.266" | NAS1130-4L-10 | 5 | 000000000 | 00000 | 000000000 | 000000 | 000000000 | 000000 | 000000000 | 0000000 |
| 1/4"-20 | 3/8" | H | 0.266" | NAS1130-4L-15 | 5 | 000000000 | 0000 | 000000000 | 00000 | 000000000 | 00000 | 000000000 | 000000 |
Helical Inserts with Installation Tools
Inserts come with a through-hole tap and installation tool. Also known as Heli-Coil inserts, they have coils that expand once installed to securely anchor the insert. All have a prong for ease of installation. An installation tool grips the prong and reduces the coil diameter, enabling the insert to fit in tapped holes. Remove the prong to insert the screw.
| Thread Size | Installed Lg. | Drill Bit Size | For Max. Hole Dia. | No. of Inserts Included | Includes | Each | |
18-8 Stainless Steel—Right-Hand Threaded | |||||||
|---|---|---|---|---|---|---|---|
| 1/4"-20 | 1/4" | H | 17/64" | 10 | Drill Bit, Through-Hole Tap, Installation Tool | 000000000 | 000000 |
| 1/4"-20 | 3/8" | H | 17/64" | 10 | Drill Bit, Through-Hole Tap, Installation Tool | 000000000 | 00000 |
| 1/4"-20 | 1/2" | H | 17/64" | 10 | Drill Bit, Through-Hole Tap, Installation Tool | 000000000 | 00000 |
| 1/4"-20 | 5/8" | H | 17/64" | 10 | Drill Bit, Through-Hole Tap, Installation Tool | 000000000 | 00000 |
| 1/4"-20 | 3/4" | H | 17/64" | 10 | Drill Bit, Through-Hole Tap, Installation Tool | 000000000 | 00000 |
18-8 Stainless Steel—Left-Hand Threaded | |||||||
| 1/4"-20 | 3/8" | 17/64" | 17/64" | 6 | Through-Hole Tap, Installation Tool | 000000000 | 00000 |
Helical Insert Assortments with Installation Tools
Assortments include various sizes of helical inserts and a tap, a drill bit, and an installation tool for each thread size. Also known as Heli-Coil inserts, the inserts have coils that expand once installed to securely anchor the insert. All have a prong for ease of installation. An installation tool grips the prong and reduces the coil diameter, enabling the insert to fit in tapped holes. Remove the prong to insert the screw.
| Includes | No. of Inserts Included | Thread Spacing | Drill Bit Size | For Max. Hole Dia. | Each | |
Inch | ||||||
|---|---|---|---|---|---|---|
18-8 Stainless Steel | ||||||
| Prong Break-Off Tool 1/4"-20 Thread × 1/4" Installed Lg. (12 Each) 1/4"-20 Thread × 3/8" Installed Lg. (12 Each) 1/4"-20 Thread × 1/2" Installed Lg. (12 Each) Drill Bit Through-Hole Tap Installation Tool | 36 | Coarse | 17/64" | 17/64" | 000000000 | 000000 |
| 1/4"-20 Thread × 3/8" Installed Lg. (12 Each) 5/16"-18 Thread × 0.469" Installed Lg. (12 Each) 3/8"-16 Thread × 0.562" Installed Lg. (12 Each) 7/16"-14 Thread × 0.656" Installed Lg. (6 Each) 1/2"-13 Thread × 3/4" Installed Lg. (6 Each) 5/8"-11 Thread × 15/16" Installed Lg. (6 Each) Drill Bits Through-Hole Taps Installation Tools | 54 | Coarse | 17/64" 21/64" 25/64" 29/64" 17/32" 21/32" | 17/64" 21/64" 25/64" 29/64" 17/32" 21/32" | 000000000 | 000000 |
Installation Tools for Helical Inserts
Screw an insert onto these tools and drive them a quarter to half-turn below the material’s surface. They’re compatible with helical inserts that have a prong.
Style F cannot be used with screw-lock inserts.
Prong Break-Off Tools for Helical Inserts
Place the tip of these tools into installed inserts and push down to trigger the spring-loaded punch to break off the prong.
For technical drawings and 3-D models, click on a part number.
| For Thread Size | Each | |
| 1/4"-20, 1/4"-28 | 000000000 | 0000000 |
Extraction Tools for Helical Inserts
Place the tip of these tools into an insert and strike a light blow to the tool’s head. Then turn the tools counterclockwise with pressure to extract the insert.
| For Thread Size | Each | |
| 10-24, 10-32, 12-24, 12-28, 1/4"-20, 1/4"-28, 1/4"-32, 1/4"-80, 5/16"-18, 5/16"-24, 5/16"-32, 3/8"-16, 3/8"-24, M5, M6, M7, M8, M10 | 000000000 | 000000 |
Installation Tools for Helical Inserts without Prong
Screw an insert onto these tools and drive them a quarter to half-turn below the material’s surface.
Tools with a hollow handle store the tip.
Replacement tips (sold separately) include one installation tip, two pins, and two springs.
Extraction Tools for Helical Inserts without Prong
Thread these tools into an insert and turn counterclockwise to extract.
Tools with a hollow handle store the tip.
Replacement tips (sold separately) come with one removal tip, two pins, and two springs.
Go/No-Go Helical Insert Threaded Plug Gauges with Handle
Check that holes tapped for helical threads are within tolerance. You’ll sometimes hear these threads referred to as Screw Thread Insert (STI) threads. To speed up tests, these gauges have a go gauge on one end and a no-go gauge on the other. The double-ended taperlock handle makes them quick to thread and unthread. It also lets you swap in new plug gauges (not included) in place of worn ones.
The go gauge checks the minimum internal thread size, and the no-go gauge checks the maximum. A part is within tolerance if it’s easy to thread the go gauge but difficult to thread the no-go gauge more than two turns.
Gauges with a certificate of accuracy traceable to NIST include verification from the manufacturer that their thread sizes are within tolerance. The certificate is also known as a certificate of compliance or a short-form certification.
Gauges with a calibration certificate traceable to NIST were calibrated in a lab. The certificate, sometimes called a test report or long-form certificate, details the tested measurements.
For technical drawings and 3-D models, click on a part number.
| Thread Size | Thread Type | Pitch Dia. Tolerance | Hardness | Material | Features | For Thread Fit | Each | |
Certificate of Accuracy Traceable to NIST | ||||||||
|---|---|---|---|---|---|---|---|---|
Class X | ||||||||
| 1/4"-20 | UNC | -0.0003" to 0.0003" | Rockwell C70 | Chrome-Plated Tool Steel | Double-Ended Taperlock Handle | Class 2B | 0000000 | 0000000 |
Calibration Certificate Traceable to NIST | ||||||||
Class X | ||||||||
| 1/4"-20 | UNC | -0.0003" to 0.0003" | Rockwell C70 | Chrome-Plated Tool Steel | Double-Ended Taperlock Handle | Class 2B | 0000000 | 000000 |