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Large-Flange™  ISO LF


MDC’s Large-Flange™ ISO LF components are an economical system of reusable and interfacing stainless steel vacuum fittings for tube sizes ranging from 2-1/2" through 20" diameters. Large-Flange™ ISO LF flanges pick up where the Kwik-Flange™ ISO KF system leaves off. These flanges can operate in high vacuum environments to pressures in the 1x10-8 Torr range. The Large-Flange™ ISO LF flange system is ideally suited for applications requiring rapid and frequent assembly and disassembly. MDC ISO LF flanges comply with all ISO specifications for vacuum mounting hardware and are compatible with most third party ISO LF flanges and components.

Large-Flange ISO LF flange assembly
Large-FlangeTM ISO LF flange assembly

  • 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 construction
Flanges 304ss
Rotatable Bolt Ring  Aluminum
O-rings Viton® or Buna-N® elastomer
Claw Clamps Aluminum
Band clamps 431ss, heat treated
Claw Clamp M8-1.25 thread, 3-4 required
M10-1.50 thread, 6-12 required
M12-1.75 thread, 8-16 required
Band clamp .250-28 thread
Bolt Type Hexagonal head, M8-1.25 thread
Nut Type Hexagonal
Torque  Band clamps: 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
Weight  3 lb maximum
Dimensions Clamp style: 3.74 OD x 2.37 ID maximum
Bolt style: 5.12 OD x 2.37 ID maximum

The MDC Large-Flange™ ISO LF 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 Large-Flange™ ISO LF flanges. Reducer flanges are available to connect different size ISO components. This section includes ISO KF and ISO LF reducer flanges for KF to KF, KF to LF and LF to LF flange Large-Flange™ ISO LF flange combinations. Hybrid adapters are available to connect ISO LF components to non ISO vacuum fittings and mounts. Some of these include Del-Seal™ CF metal seal flanges, ANSI ASA flanges, Swagelok® compression tube fittings and VCR® metal gasket tube fittings and national pipe thread fittings. For more details and information on hybrid adapters please reference Section 1.5 in this catalog.

MDC Large-Flange™ ISO LF flanges are available in nine standard maximum tube sizes including 2-1/2", 3", 4", 6", 8", 10", 12-3/4", 16" and 20" diameters. Each of these basic flanges are also offered in blanked formats which are suitable for custom modification or to blank-off unused chamber ports. Typically, U.S. tube sizes are specified in inches and identified by their outside diameters. MDC standard ISO LF flange size designations are as follows...
L250 for 2.50", L300 for 3.00", L400 for 4.00", L600 for 6.00", L800 for 8.00", L1000 for 10.0", L1200 for 12.75", L1600 for 16.0" and L2000 for 20.0" tube diameters. 

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 on the right side gives a quick comparison between inch and metric ISO flange sizes. 

For product listing, features and specifications click on links below
 NW63 Flange Assembly
 NW63 Flange 
 NW80  Flange Assembly
 NW80 Flange 
 NW100 Flange Assembly
 NW100 Flange 
 NW160 Flange Assembly
 NW160 Flange 
 NW200 Flange Assembly
 NW200 Flange 
 NW250 Flange Assembly
 NW250 Flange 
 NW320 Flange Assembly
 NW320 Flange 
 NW400 Flange Assembly
 NW400 Flange 
 NW500 Flange Assembly
 NW500 Flange 
These flanges provide a vacuum mount interface for tube diameters from 2.50 inches. For tube diameters below this,
Go to Kwik-Flange™ ISO KF


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

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