ISO and KF Centering Rings

  • Centering rings are used to mostly in vacuum fitings to improve seal performance

ISO-KF FITTING COMPONENTS — Centering Rings

Centering Ring Fitting Size Centering Ring O-Ring Size USA Centering Ring O-Ring Metric Alternative
NW KF ISO2861-1 AS568 USA Size Cross Section
mm (in)
Inside Diameter
mm (in)
Cross Section
mm (in)
Inside Diameter
mm (in)
NW10 KF10 ISO10 -312 5.33 (0.210) 15.00 (0.600) 5.00 (0.197) 15.00 (0.600)
NW16 KF16 ISO16 -314 5.33 (0.210) 18.42 (0.725) 5.00 (0.197) 18.00 (0.706)
NW25 KF25 ISO25 -320 5.33 (0.210) 27.94 (1.100) 5.00 (0.197) 28.00 (1.102)
NW40 KF40 ISO40 -326 5.33 (0.210) 40.64 (1.600) 5.00 (0.197) 42.00 (1.653)
NW50 KF50   -330 5.33 (0.210) 53.34 (2.100) 5.00 (0.197) 55.00 (2.165)
NW63 KF63   -336 5.33 (0.210) 72.39 (2.850) 5.00 (0.197) 75.57 (2.975)
NW80 KF80   -340 5.33 (0.210) 85.09 (3.350) 5.00 (0.197) 88.27 (3.475)
NW100 KF100   -346 5.33 (0.210) 104.14 (4.100) 5.00 (0.197) 107.32 (4.225)
NW160 KF160   -361 5.33 (0.210) 151.76 (5.975) 5.00 (0.197) 158.12 (6.225)

Centering Ring USA or Metric O-Ring sizes can be used effectively depending on the application and gland design

 
O-Ring Material Description Relative Cost Typical Delivery
Viton® (FKM)
Low permeation and high temperature resistance makes this compound ideal for vacuum applications for temperatures up to 400° F.
1 to 4 Weeks
Silicone
Good chemical resistance low and high temperature capabilities for temperatures up to 400° F.
1 to 4 Weeks
Markez® (FFKM)
Excellent chemical compatibility and high temperature resistance up to 615° F.
1 to 4 Weeks

Many other elastomeric compounds are available.

Centering Ring Material  Relative Cost  Typical Delivery 
Aluminum 6061 1 to 4 Weeks
Stainless Steel 1 to 4 Weeks
PTFE 1 to 4 Weeks

New Customer Hotline: 800-775-6525

Existing Customer Specialist: 603-468-3600 or repeat customers

Marco Rubber & Plastics
PO Box 1150
Seabrook, NH 03874

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