O-Ring Groove Design

    Diametral
Squeeze
(Minimum)		 Gland Depth Groove Width
+/-.003		 Diametral
Clearance
(Maximum)		  
Uniform Dash
Number		 Actual
Cross Section
Diameter		 Dynamic1 Static Dynamic1
+.000
-.001		 Static
+.000
-.004		 No
Backup
Ring		 One
Backup
Ring		 Two
Backup
Rings		 500 PSI 1500 PSI Eccentricity
(Maximum)		 Radius
F G D R
-.001 .040 +.003 .004 .006 .033 .031 .056 - - .005 .0025 .002 .010
-.002 .050 +.003 .005 .008 .042 .039 .070 - - .006 .003 .002 .010
-.003 .060 +.003 .009 .009 .051 .048 .084 - - .007 .0035 .002 .016
-.004 thru -.050 .070 +.003 .007 .011 .060 .056 .098 .140 .207 .008 .004 .002 .016
-.102 thru -.178 .103 +.003 .010 .015 .090 .085 .144 .173 .240 .009 .004 .002 .016
-.201 thru -.284 .139 +.004 .014 .021 .121 .114 .195 .210 .277 .010 .006 .003 .031
-.309 thru -.395 .210 +.005 .021 .032 .184 .173 .294 .313 .412 .011 .007 .004 .031
-.425 thru -.475 .275 +.006 .028 .042 .241 .227 .385 .410 .540 .012 .008 .005 .047

Note 1. The following sizes are not normally recommended for dynamic service:
  [ -001 thru -003 ]  [ -013 thru -050 ]  [ -117 thru -118 ]   [ -223 thru -284 ]   [ 350 thru -395 ]   [ -164 thru -475 ]
Note 2. Clearances shown are based on 70 durometer values.
Note 3. TIR between groove and adjacent bearing surface. Surfaces and corners must be free of tool marks and scratches.

Example Calculations to Determine O-Ring Groove Dimensions:

Rod Seal Example

Given:

Rod Diameter C = .500
O-ring Cross Section W = 3/32 nominal
Dynamic application
No back-ups required

Determine:

O-ring size = AS-568-112 (1/2 ID x 3/32 W nominal dimensions)

Gland depth F = .090 +.000 -.001 (from chart)

Groove width G = .144 +/-.003 (from chart)

Rod Gland D = C + 2F = .500 + 2 x .090 = .680

Piston Seal Example

Given:

Cylinder Bore A = 1.000
O-ring Cross Section W = 1/8 nominal
Static application
No back-ups required

Determine:

O-ring size = AS-568-210 (1 OD x 1/8 W nominal dimensions)

Gland depth F = .114 + .000 - .004 (from chart)

Groove width G = .195 +/-.003 (from chart)

Rod Gland D = A - 2F = 1.000 -2 x .114 = .772

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Ponn Machine Cutting Co., Inc.
20A Cross Street
Woburn MA, 01801

Call Us: (781) 937-3373

Fax: (781) 937-0372