Please select your country or region to be
directed to the appropriate Lesker site.

Representative Image

Rotatable Tapped-Blank 316LN SS Standard ConFlat® (CF) UHV Flanges

The CF (ConFlat) flange is the most widely used for high vacuum and UHV applications. Many gauges, instruments, accessories and feedthroughs are available on this flange system.

The seal mechanism is a knife-edge that is machined below the flange's flat surface. As the bolts of a flange-pair are tightened, the knife-edges make annular grooves on each side of a soft metal gasket. The extruded metal fills all the machining marks and surface defects in the flange, yielding a leak-tight seal. The CF seal operates from 760 torr (103 mbar) to < 1 x 10-13 Torr (< 1.3 x 10-13 mbar), and within the temperature range -196° C to 450° C (depending on material). Flange sizes in North America are normally referenced by their outside diameter (O.D.). However, in Europe and much of Asia, the nominal internal diameter (nominal I.D.) of the largest tube that can be welded to a bored flange is usually referenced in their nomenclature.

ConFlat flanges are offered in four versions:

  • Fixed flange: is a one piece design where the bolt-hole orientation is fixed with respect to that fitting.
  • Rotatable flange: is comprised of two parts, an inner weld ring and outer bolt ring. This enables the bolt ring to rotate about the inner weld ring.

Both Fixed and Rotatable flanges are available with your choice of clearance-holes or tapped holes.

  • Clearance-holes: Are through-holes that allow adequate clearance for bolts to go through both flanges and secured by nuts or plate nuts.
  • Tapped holes: Are imperial or metric threaded holes machined through the flange. This allows a clearance-hole flange to be connected without the need for nuts or plate nuts. Be aware of a components bolt hole orientation when selecting tapped flanges.

316LN Stainless Steel Features:

  • Harder than their 304L counterparts (170 Brinell Hardness) making them ideal for frequently dismantled chamber ports
  • Electro-slag Remelt (ESR) to improve grain homogeneity and remove gross macro segregation
  • Lower magnetic permeability (µ ≤ 1.005 vs. 1.03 for 304L SS) for applications sensitive to magnetic materials
ISO Standard KJLC flanges & gaskets are compatible with flanges produced to the ISO3669-2017 & ASTM E2734/E2734M-10 standards.

Contact Us
Contact Us
Questions? Let's Talk!
Contact your dedicated Lesker sales team today.
+1 800 245 1656
Got VacuCADSM?
VacuCAD is a free library containing thousands of 2D CAD drawings (in DXF format) and 3D Models (in STP format) for many of our standard vacuum components and chambers. Please Log in

Ordering Table

(Click column headers to sort data)


Overstock Item - Clearance Pricing for Available Inventory
Flange Selection Guide
With a variety of flanges to choose from, the Flange Selection Guide is designed to help you find one to meet your vacuum requirements. Shop Now!
Can't find the flange you need or want a custom configuration? Please call us at +1 800 245 1656 or email with your inquiry.
Contact Us - Rotatable Tapped-Blank 316LN SS Standard ConFlat® (CF) UHV Flanges