Bolt-Together High-Vacuum Fittings for Stainless Steel Tubing

For high-vacuum systems with tube sizes too large for quick-clamp (KF) fittings, choose these bolt-together fittings. Also known as ISO-F flanges, these fittings work with tube sizes starting at 2 1/2" OD and are rated for higher levels of vacuum than quick-clamp fittings. Not for use in pressure applications.
To complete the bolt-end connection, you'll need a ring and a bolt kit (both sold separately).
For technical drawings and 3-D models, click on a part number.

Adapter, Tube ×
Socket-Connect Tube
Adapters | |||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Bolt Hole | Bolt Kits | ||||||||||||||
For Tube OD | Flange OD | High-Vacuum Flange Size | Socket Dp. | High Vacuum Connection Type | Material | Max. Vacuum | Bolt Circle Dia. | Dia. | No. of | For Bolt Dia. | Bolts Included | Each | Each | ||
2 1/2" | 5.12" | 63 | 1/4" | ISO-F | 304 Stainless Steel | 1 × 10 -9 torr @ 72° F | 4 21/64" | 23/64" | 4 | 5/16" | No | 0000000 | 000000 | 0000000 | 000000 |
3" | 5.71" | 80 | 1/4" | ISO-F | 304 Stainless Steel | 1 × 10 -9 torr @ 72° F | 4 59/64" | 23/64" | 8 | 5/16" | No | 0000000 | 000000 | 0000000 | 00000 |
4" | 6 1/2" | 100 | 1/4" | ISO-F | 304 Stainless Steel | 1 × 10 -9 torr @ 72° F | 5 45/64" | 23/64" | 8 | 5/16" | No | 0000000 | 000000 | 0000000 | 00000 |
6" | 8.86" | 160 | 3/8" | ISO-F | 304 Stainless Steel | 1 × 10 -9 torr @ 72° F | 7 7/8" | 7/16" | 8 | 3/8" | No | 0000000 | 000000 | 0000000 | 00000 |

Adapters | |||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Bolt Hole | Bolt Kits | ||||||||||||||
For Tube OD | Flange OD | High-Vacuum Flange Size | Wall Thick. | High Vacuum Connection Type | Material | Max. Vacuum | Bolt Circle Dia. | Dia. | No. of | For Bolt Dia. | Bolts Included | Each | Each | ||
2 1/2" | 5.12" | 63 | 0.065" | ISO-F | 304 Stainless Steel | 1 × 10 -9 torr @ 72° F | 4 21/64" | 23/64" | 4 | 5/16" | No | 0000000 | 0000000 | 0000000 | 000000 |
3" | 5.71" | 80 | 0.065" | ISO-F | 304 Stainless Steel | 1 × 10 -9 torr @ 72° F | 4 59/64" | 23/64" | 8 | 5/16" | No | 000000 | 000000 | 0000000 | 00000 |
4" | 6 1/2" | 100 | 0.083" | ISO-F | 304 Stainless Steel | 1 × 10 -9 torr @ 72° F | 5 45/64" | 23/64" | 8 | 5/16" | No | 0000000 | 000000 | 0000000 | 00000 |
6" | 8.86" | 160 | 0.109" | ISO-F | 304 Stainless Steel | 1 × 10 -9 torr @ 72° F | 7 7/8" | 7/16" | 8 | 3/8" | No | 0000000 | 000000 | 0000000 | 00000 |

Caps | ||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Bolt Hole | Bolt Kits | |||||||||||||
For Tube OD | Flange OD | High-Vacuum Flange Size | High Vacuum Connection Type | Material | Max. Vacuum | Bolt Circle Dia. | Dia. | No. of | For Bolt Dia. | Bolts Included | Each | Each | ||
2 1/2" | 5.12" | 63 | ISO-F | 304 Stainless Steel | 1 × 10 -9 torr @ 72° F | 4 21/64" | 23/64" | 4 | 5/16" | No | 0000000 | 000000 | 0000000 | 000000 |
3" | 5.71" | 80 | ISO-F | 304 Stainless Steel | 1 × 10 -9 torr @ 72° F | 4 59/64" | 23/64" | 8 | 5/16" | No | 0000000 | 000000 | 0000000 | 00000 |
4" | 6 1/2" | 100 | ISO-F | 304 Stainless Steel | 1 × 10 -9 torr @ 72° F | 5 45/64" | 23/64" | 8 | 5/16" | No | 0000000 | 000000 | 0000000 | 00000 |
6" | 8.86" | 160 | ISO-F | 304 Stainless Steel | 1 × 10 -9 torr @ 72° F | 7 7/8" | 7/16" | 8 | 3/8" | No | 0000000 | 000000 | 0000000 | 00000 |

Flanged Connection | Material | ||||||||
---|---|---|---|---|---|---|---|---|---|
For Tube OD | For Flange OD | For High-Vacuum Flange Size | High Vacuum Connection Type | O-Ring | Inner Ring | Max. Vacuum | Max. Temp., °F | Each | |
2 1/2" | 5.12" | __ | ISO-F | Viton® Fluoroelastomer Rubber | 304 Stainless Steel | 1 × 10 -9 torr @ 72° F | 400° | 0000000 | 000000 |
3" | 5.71" | 80 | ISO-F | Viton® Fluoroelastomer Rubber | 304 Stainless Steel | 1 × 10 -9 torr @ 72° F | 400° | 000000 | 00000 |
4" | 6.5" | 100 | ISO-F | Viton® Fluoroelastomer Rubber | 304 Stainless Steel | 1 × 10 -9 torr @ 72° F | 400° | 0000000 | 00000 |
6" | 8.86" | 160 | ISO-F | Viton® Fluoroelastomer Rubber | 304 Stainless Steel | 1 × 10 -9 torr @ 72° F | 400° | 0000000 | 00000 |
Rings for Claw-Clamp and Bolt-Together
High-Vacuum Fittings for Stainless Steel Tubing

- For Use With: Air
- Max. Temperature: 400° F
- Tubing: Use with 304/304L Stainless Steel or 316/316L Stainless Steel
Create airtight seals in high-vacuum systems by placing these rings between two claw-clamp (ISO-K) or bolt-together (ISO-F) fittings. They contain a Viton® fluoroelastomer O-ring—when you clamp or bolt your fittings together, the O-ring compresses to establish the seal.
For technical drawings and 3-D models, click on a part number.
Claw-Clamp Connection | Flanged Connection | Material | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
For Tube OD | For Flange OD | For High-Vacuum Flange Size | High Vacuum Connection Type | For Tube OD | For Flange OD | For High-Vacuum Flange Size | High Vacuum Connection Type | O-Ring | Inner Ring | Max. Vacuum | Each | |
2 1/2" | 3.74" | 63 | ISO-K | 2 1/2" | 5.12" | __ | ISO-F | Viton® Fluoroelastomer Rubber | 304 Stainless Steel | 1 × 10 -9 torr @ 72° F | 0000000 | 000000 |
3" | 4.33" | 80 | ISO-K | 3" | 5.71" | 80 | ISO-F | Viton® Fluoroelastomer Rubber | 304 Stainless Steel | 1 × 10 -9 torr @ 72° F | 000000 | 00000 |
4" | 5.12" | 100 | ISO-K | 4" | 6.5" | 100 | ISO-F | Viton® Fluoroelastomer Rubber | 304 Stainless Steel | 1 × 10 -9 torr @ 72° F | 0000000 | 00000 |
6" | 7.09" | 160 | ISO-K | 6" | 8.86" | 160 | ISO-F | Viton® Fluoroelastomer Rubber | 304 Stainless Steel | 1 × 10 -9 torr @ 72° F | 0000000 | 00000 |