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Kwik-Flange™  ISO KF

MDC’s Kwik-Flange™ ISO KF components are an economical system of reusable interfacing stainless steel vacuum fittings for tube sizes ranging from 1/2" through 2"
diameters. These flanges can operate in high vacuum environments to pressures in the 1x10-8 Torr range. The Kwik-Flange™ ISO KF flange system is ideally suited for
applications requiring rapid and frequent assembly and disassembly. MDC ISO KF flanges comply with all ISO specifications for vacuum mounting hardware and are
compatible with most third party ISO KF flanges and components.

Kwik-Flange ISO KF Assembly
Kwik-Flange ISO KF Assembly

  • Vacuum rated to 1x10-8 Torr
  • Bakeable to 150°C
  • Fast connect and disconnect
  • Economical reusable fittings
  • Genderless geometry
  • Rotatable bolt ring adapter
  • Elastomer gasket seal
  • Varied fastening methods
  • ISO KF and LF compatible
  • Specialty fittings available
  • Type 304 stainless steel
Flanges 304ss
O-rings Viton®, Buna-N® or Silicone elastomer
Clamps, hinged & bulkhead Aluminum
Clamp Type Hinged with 10-32 thread
Bulkhead Type Hexagonal head bolts, 10-32 thread
Nut Type Hexagonal
Torque Clamp: Finger tight
Bolts: 7-10 lb-ft
Vacuum Range 1x10-8 Torr
Temp.Range Minimum Intermittent Sustained
Viton® -20°C   200°C 150°C
Buna-N® -20°C   100°C 80°C
Silicone -20°C   200°C 150°C
Weight  1/4 lb maximum
Dimensions 1.18 OD x .680 ID maximum

The MDC Kwik-Flange™ ISO KF family of modular building-block components includes all of the commonly used standard hardware and fittings. Virtually all standard MDC feedthroughs and accessories are available for use with Kwik-Flange™ ISO KF flanges.

Reducer flanges are available to connect different size ISO components. This catalog includes ISO KF and ISO LF reducer flanges for KF to KF, KF to LF and LF to LF flange combinations. Hybrid adapters are available to connect ISO KF components to other non ISO vacuum fittings and mounts. These include Del-Seal™ CF metal seal flanges, ANSI ASA flanges, Swagelok® compression tube fittings and VCR® metal gasket tube fittings, national pipe thread fitting, etc. 

MDC Kwik-Flange™ ISO KF flanges are  available in four standard maximum tube sizes including 3/4", 1", 1-1/2" and 2" diameters. Each of these basic flanges are then offered in weldable formats, prepped for varying smaller tube sizes. Typically, U.S. tube sizes are specified in inches and identified by their outside diameters. MDC standard ISO KF flange size designations are as follows... K075 for 0.75", K100 for 1.00", K150 for 1.50" and K200 for 2.00" tube diameters. It’s worth mentioning that, with the exception of the centering ring locater diameter, three of the ISO KF flanges depicted in the diagram below, namely NW 10, 20 and 32, are identical to NW 16, 25 and 40 respectively. These latter flanges being the standard for all of MDC’s ISO KF fitted products equipment fitted with NW 10, 20 and 32 flanges can mate them with MDC NW 16, 25 and 40, respectively, by using MDC’s reducer centering ring. The reducer centering ring is constructed with two different size tubular rims or extensions which mate with the respective flange size centering ring locater groove or counterbore.

For product listing, features and specifications click on links below
 NW16 Flange Assembly
 NW16 Flange 
 NW25  Flange Assembly
 NW25 Flange 
 NW40 Flange Assembly
 NW40 Flange 
 NW50 Flange Assembly
 NW50 Flange 
These flanges provide a vacuum mount interface for tube diameters up to 2.00 inches. For tube diameters above this,
Go to Large-Flange™ ISO LF


Inch-Metric ISO Comparision

MDC O.D Inches ISO I.D. mm Inches
Kwik-Flange™ ISO KF
K075 0.75 NW16 16 0.63
K100 1.00 NW25 25 0.98
K150 1.50 NW40 40 1.57
K200 2.00 NW50 50 1.97
Large-Flange™ ISO LF 
L250 2.50 NW63 63 2.48
L300 3.00 NW80 80 3.15
L400 4.00 NW100 100 3.94
L600 6.00 NW160 160 6.30
L800 8.00 NW200 200 7.87
L1000 10.00 NW250 250 9.84
L1200 12.75 NW320 320 12.60
L1600 16.00 NW400 400 15.75
L2000 20.00 NW500 500 19.69
Go to Large-Flange™ ISO LF

As previously noted, Kwik-Flange™ ISO KF flanges provide a vacuum mount interface for tube diameters up to 2.00 inches. For tube diameters above this, Large-Flange™ ISO LF flanges are used. Kwik-Flange™ and Large-Flange™ flanges are part of one and the same family of ISO standard elastomer sealed mounts. Together they provide a complete range of vacuum mounts for 0.75 to 20.0 inch diameter tubes. ISO KF and LF sealing mechanisms are similar but their fastening and clamping methods differ. Due to the wide variation of references used by ISO flange manufacturers, MDC emphasizes the use of the standard ISO NW reference. Note that for all practical purposes, NW and DN references are identical. Large-Flange™ ISO LF flanges are presented immediately after the Kwik-Flange™ ISO KF flanges. 

In general, MDC components compare with international components using an inch-to millimeter ratio. U.S. sizes refer to a tube’s outside diameter, whereas international sizes refer to a tube’s inside diameter. The chart shown on right gives a quick comparison between inch and metric ISO flange sizes. 

 Related Topics
 Kwik-Flange™ ISO KF Parts Identification
 Kwik-Flange™ ISO KF Installation
 Large-Flange™ ISO LF Introduction
 ISO KF & LF Fittings Introduction
 ANSI ASA Flanges Introduction