O-ring grooves

An AS568 -214 O-ring (0.139 in cross-section) in a face-seal groove takes a gland depth L of 0.104 ±0.003 in and a groove width G of 0.182 in for liquids, for 20–30 % squeeze. Enter a dash number for its groove, or type your own gland depth and width, and the ring is drawn squeezed in its gland with the squeeze, fill and stretch checked against the seal makers’ usual ranges.

The stored grooves are face (axial) seals; for a static or reciprocating radial gland the page derives a starting gland from the design chart and says so.

AS568 dash number

Gland

Face, staticRadial, staticRadial, dynamic

Gland depth L

L tolerance ±

Groove width G

Groove inner Ø (optional)

Ring ID 0.984

Squeeze, fill and stretch are inside the seal makers' usual ranges.

Squeeze, (W − L) / W: 25.2%

At the tolerance limits (W ±0.004, L ±0.003): 20.7–29.4%
Usual band (Parker ORD 5700 Design Chart 4-3 (face seal glands)): 20–30%
Gland fill, ring area / (L × G); usual 60–85 %: 80.2%
Fill at the worst tolerances (largest W, shallowest L): 87.4%
ID stretch onto the seat Ø; at most 5 %: enter the seat Ø
Cross-section W: 0.139in (3.53 mm)

Face seal: with pressure from inside, size the groove's outer Ø to the ring's OD (the ring pressed outward); with pressure from outside, its inner Ø to the ring's ID (Parker ORD 5700 § 4.3).

Dash	ID	Cross section	Groove width G (liquids)	Gland depth L	Gland depth ±	Squeeze	Seal	Unit
-006	0.114	0.07	0.104	0.052	0.002	19–32%	face	in
-010	0.239	0.07	0.104	0.052	0.002	19–32%	face	in
-014	0.489	0.07	0.104	0.052	0.002	19–32%	face	in
-020	0.864	0.07	0.104	0.052	0.002	19–32%	face	in
-028	1.364	0.07	0.104	0.052	0.002	19–32%	face	in
-110	0.362	0.103	0.139	0.077	0.003	20–30%	face	in
-210	0.734	0.139	0.182	0.104	0.003	20–30%	face	in
-214	0.984	0.139	0.182	0.104	0.003	20–30%	face	in
-218	1.234	0.139	0.182	0.104	0.003	20–30%	face	in
-222	1.484	0.139	0.182	0.104	0.003	20–30%	face	in
-226	1.984	0.139	0.182	0.104	0.003	20–30%	face	in
-230	2.484	0.139	0.182	0.104	0.003	20–30%	face	in
-325	1.475	0.21	0.28	0.157	0.005	21–30%	face	in
-330	2.1	0.21	0.28	0.157	0.005	21–30%	face	in
-425	4.475	0.275	0.352	0.206	0.005	21–29%	face	in
-430	5.1	0.275	0.352	0.206	0.005	21–29%	face	in

What makes an O-ring groove right?

Three numbers: the squeeze, how much the gland depth compresses the cross-section, which depends on the gland type; the fill, the ring’s section as a share of the groove’s, kept to about 60–85 % so the ring has room to swell and expand with heat; and the stretch of the ring’s ID onto its seat, at most about 5 %, since a stretched ring thins and loses squeeze. Check each at the tolerance limits, not only at nominal: the worst case is the largest cross-section in the shallowest gland.