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Flanged Ultra-High-Vacuum Fittings for Stainless Steel Tubing
- For Use With: Air
- Temperature Range:
Flanges: -300° to 800° F
Gaskets: Not Rated - Tubing: Use with 304/304L and 316/316L stainless steel
- Specifications Met:
Flanges: ASTM A240, ASTM E45, ASTM E12
Gaskets: ASTM B152-179, ASTM F68
Create access points in ultra-high-vacuum lines or chambers by bolting two same-size flanges together with a copper gasket (sold separately) between them. The flanges’ sharp edges dig into the copper gasket and form an extremely tight seal, which means they handle higher vacuum pressures than other high-vacuum fittings with rubber gaskets. Also known as CF, Conflat, and UHV fittings, use them in vacuum coating, heat treating, and drying applications, as well as for leak testing and analyzing gases. They’re stainless steel so they resist rusting.
Fittings with a rotating flange turn so you can easily match up the bolt holes with another flange that may be misaligned.
Butt-weld flanges provide a flush connection for smooth flow through your line.
Socket-connect flanges are easier to weld than butt-weld flanges because they don’t need to align perfectly to tubing; insert the tubing into the socket end and weld together.
Caps are also known as blind flanges.
Bolt kits are required to make a complete connection.

Bolt Holes | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| For Tube OD | Flange OD | High-Vacuum Flange Size | High Vacuum Connection Type | Bolt Circle Dia. | Dia. | No. of | Bolts Included | No. of Bolt Kits Required | Lg. | Max. Vacuum | Material | Appearance | Each | |
Fixed × Rotating | ||||||||||||||
| 3/4" | 1 21/64" | 16 | CF | 1 1/16" | 11/64" | 6 | No | 2 | 3" | 10 -13 torr @ 72° F | 304 Stainless Steel | Polished | 0000000 | 000000 |
| 1 1/2" | 2 3/4" | 40 | CF | 2 5/16" | 17/64" | 6 | No | 2 | 4 15/16" | 10 -13 torr @ 72° F | 304 Stainless Steel | Polished | 0000000 | 00000 |
| 2 1/2" | 4 1/2" | 63 | CF | 3 5/8" | 21/64" | 8 | No | 2 | 6 11/16" | 10 -13 torr @ 72° F | 304 Stainless Steel | Polished | 0000000 | 000000 |
| 4" | 6" | 100 | CF | 5 1/8" | 21/64" | 16 | No | 4 | 8 5/8" | 10 -13 torr @ 72° F | 304 Stainless Steel | Polished | 0000000 | 000000 |

Bolt Holes | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| For Tube OD | Flange OD | High-Vacuum Flange Size | High Vacuum Connection Type | Bolt Circle Dia. | Dia. | No. of | Bolts Included | No. of Bolt Kits Required | Max. Vacuum | Material | Appearance | Each | |
Rotating | |||||||||||||
| 3/4" | 1 21/64" | 16 | CF | 1 1/16" | 11/64" | 6 | No | 2 | 10 -13 torr @ 72° F | 304 Stainless Steel | Polished | 0000000 | 0000000 |
| 1 1/2" | 2 3/4" | 40 | CF | 2 5/16" | 17/64" | 6 | No | 2 | 10 -13 torr @ 72° F | 304 Stainless Steel | Polished | 0000000 | 000000 |
| 2 1/2" | 4 1/2" | 63 | CF | 3 5/8" | 21/64" | 8 | No | 2 | 10 -13 torr @ 72° F | 304 Stainless Steel | Polished | 0000000 | 000000 |
| 4" | 6" | 100 | CF | 5 1/8" | 21/64" | 16 | No | 4 | 10 -13 torr @ 72° F | 304 Stainless Steel | Polished | 0000000 | 000000 |


Butt-Weld Tube Connection | Flanged Tube Connection | Bolt Holes | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| For Tube OD | Wall Thick. | For Tube OD | Flange OD | High-Vacuum Flange Size | High Vacuum Connection Type | Bolt Circle Dia. | Dia. | No. of | Bolts Included | No. of Bolt Kits Required | Lg. | Max. Vacuum | Material | Appearance | Each | |
Fixed | ||||||||||||||||
| 3/4" | 0.049" | 3/4" | 1 21/64" | 16 | CF | 1 1/16" | 11/64" | 6 | No | 1 | 1 1/2" | 10 -13 torr @ 72° F | 304 Stainless Steel | Polished | 0000000 | 000000 |
| 3/4" | 0.06" | 3/4" | 1 21/64" | 16 | CF | 1 1/16" | 11/64" | 6 | No | 1 | 9/16" | 10 -13 torr @ 72° F | 304 Stainless Steel | Polished | 0000000 | 00000 |
| 1 1/2" | 0.065" | 1 1/2" | 2 3/4" | 40 | CF | 2 5/16" | 17/64" | 6 | No | 1 | 2 15/32" | 10 -13 torr @ 72° F | 304 Stainless Steel | Polished | 0000000 | 00000 |
| 2 1/2" | 0.065" | 2 1/2" | 4 1/2" | 63 | CF | 3 5/8" | 21/64" | 8 | No | 1 | 3 3/8" | 10 -13 torr @ 72° F | 304 Stainless Steel | Polished | 0000000 | 000000 |
| 4" | 0.083" | 4" | 6" | 100 | CF | 5 1/8" | 21/64" | 16 | No | 4 | 4 5/16" | 10 -13 torr @ 72° F | 304 Stainless Steel | Polished | 0000000 | 000000 |
Rotating | ||||||||||||||||
| 3/4" | 0.06" | 3/4" | 1 21/64" | 16 | CF | 1 1/16" | 11/64" | 6 | No | 1 | 9/16" | 10 -13 torr @ 72° F | 304 Stainless Steel | Polished | 0000000 | 00000 |


Socket-Connect Tube Connection | Flanged Tube Connection | Bolt Holes | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| For Tube OD | Socket Dp. | For Tube OD | Flange OD | High-Vacuum Flange Size | High Vacuum Connection Type | Bolt Circle Dia. | Dia. | No. of | Bolts Included | No. of Bolt Kits Required | Lg. | Max. Vacuum | Material | Appearance | Each | |
Fixed | ||||||||||||||||
| 3/4" | 7/64" | 3/4" | 1 21/64" | 16 | CF | 11/16" | 3/16" | 6 | No | 1 | 5/16" | 10 -13 torr @ 72° F | 304 Stainless Steel | Polished | 0000000 | 000000 |
| 1 1/2" | 13/64" | 1 1/2" | 2 3/4" | 40 | CF | 2 5/16" | 17/64" | 6 | No | 1 | 1/2" | 10 -13 torr @ 72° F | 304 Stainless Steel | Polished | 0000000 | 00000 |
| 2 1/2" | 3/8" | 2 1/2" | 4 1/2" | 63 | CF | 3 5/8" | 21/64" | 8 | No | 1 | 11/16" | 10 -13 torr @ 72° F | 304 Stainless Steel | Polished | 0000000 | 00000 |
| 4" | 7/16" | 4" | 6" | 100 | CF | 5 1/8" | 21/64" | 16 | No | 2 | 25/32" | 10 -13 torr @ 72° F | 304 Stainless Steel | Polished | 0000000 | 000000 |
Rotating | ||||||||||||||||
| 3/4" | 1/8" | 3/4" | 1 21/64" | 16 | CF | 11/16" | 3/16" | 6 | No | 1 | 5/16" | 10 -13 torr @ 72° F | 304 Stainless Steel | Polished | 0000000 | 00000 |
| 1 1/2" | 13/64" | 1 1/2" | 2 3/4" | 40 | CF | 2 5/16" | 17/64" | 6 | No | 1 | 1/2" | 10 -13 torr @ 72° F | 304 Stainless Steel | Polished | 0000000 | 00000 |
| 2 1/2" | 3/8" | 2 1/2" | 4 1/2" | 63 | CF | 3 5/8" | 21/64" | 8 | No | 1 | 11/16" | 10 -13 torr @ 72° F | 304 Stainless Steel | Polished | 0000000 | 00000 |
| 4" | 7/16" | 4" | 6" | 100 | CF | 5 1/8" | 21/64" | 16 | No | 2 | 25/32" | 10 -13 torr @ 72° F | 304 Stainless Steel | Polished | 0000000 | 000000 |

Bolt Holes | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| For Tube OD | Flange OD | High-Vacuum Flange Size | High Vacuum Connection Type | Bolt Circle Dia. | Dia. | No. of | Bolts Included | No. of Bolt Kits Required | Max. Vacuum | Material | Appearance | Each | |
Fixed × Rotating × Rotating | |||||||||||||
| 3/4" | 1 21/64" | 16 | CF | 1 1/16" | 11/64" | 6 | No | 3 | 10 -13 torr @ 72° F | 304 Stainless Steel | Polished | 0000000 | 0000000 |
| 1 1/2" | 2 3/4" | 40 | CF | 2 5/16" | 17/64" | 6 | No | 3 | 10 -13 torr @ 72° F | 304 Stainless Steel | Polished | 0000000 | 000000 |
| 2 1/2" | 4 1/2" | 63 | CF | 3 5/8" | 21/64" | 8 | No | 3 | 10 -13 torr @ 72° F | 304 Stainless Steel | Polished | 0000000 | 000000 |
| 4" | 6" | 100 | CF | 5 1/8" | 21/64" | 16 | No | 6 | 10 -13 torr @ 72° F | 304 Stainless Steel | Polished | 0000000 | 000000 |

Bolt Holes | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| For Tube OD | Flange OD | High-Vacuum Flange Size | High Vacuum Connection Type | Bolt Circle Dia. | Dia. | No. of | Bolts Included | No. of Bolt Kits Required | Lg. | Max. Vacuum | Material | Appearance | Each | |
Fixed | ||||||||||||||
| 3/4" | 1 21/64" | 16 | CF | 1 1/16" | 11/64" | 6 | No | 1 | 5/16" | 10 -13 torr @ 72° F | 304 Stainless Steel | Polished | 0000000 | 000000 |
| 1 1/2" | 2 3/4" | 40 | CF | 2 5/16" | 17/64" | 6 | No | 1 | 1/2" | 10 -13 torr @ 72° F | 304 Stainless Steel | Polished | 0000000 | 00000 |
| 2 1/2" | 4 1/2" | 63 | CF | 3 5/8" | 21/64" | 8 | No | 1 | 11/16" | 10 -13 torr @ 72° F | 304 Stainless Steel | Polished | 0000000 | 00000 |
| 4" | 6" | 100 | CF | 5 1/8" | 21/64" | 16 | No | 2 | 25/32" | 10 -13 torr @ 72° F | 304 Stainless Steel | Polished | 0000000 | 000000 |

| For Flange OD | For High-Vacuum Flange Size | Bolt Dia. | Thread Size | No. of Bolts Included | No. of Nuts Included | No. of Washers Included | Bolt Material | Each | |
| 1 21/64" | 16 | 0.164" | 8-32 | 6 | 6 | 12 | 18-8 Stainless Steel | 0000000 | 00000 |
| 2 3/4" | 40 | 1/4" | 1/4"-28 | 6 | 6 | 12 | 18-8 Stainless Steel | 0000000 | 00000 |
| 4 1/2" | 63 | 5/16" | 5/16"-24 | 8 | 8 | 16 | 18-8 Stainless Steel | 0000000 | 00000 |
| 6" | 100 | 5/16" | 5/16"-24 | 16 | 16 | 32 | 18-8 Stainless Steel | 0000000 | 00000 |


























