"Ecnerwal" wrote in message
...
In article ,
Rich Grise wrote:

The machinist called me over and asked me to help him design an o-ring
groove. We looked up a chart at
http://www.parker.com/literature/ORD...g_Handbook.pdf

and on page 89 of the above PDF, there's a chart: Design guide 4-2.

It's clear that for nominal 1/4" (actual width .275 ± .006) the gland
depth
(dim. L) is .226-.229.

But on the chart, it seems to indicate that the groove width, G, for a
nominal 1/4 width, is .375-.380, which he thinks (and I tend to agree,
but
I'm not the machinist - I just draw the pretty pictures) is too wide and
the o-ring would flop around or something. He thinks the groove width
should come from the line above, and be .281-.286.

Anyone got the definitive answer for that?

Thanks 10E9 in advance!
Rich

Well, this is the cheat sheet I've been using for decades for inch-sized
o-rings on vacuum systems. Since it clearly doesn't match any of what
you posted, perhaps our inch-sized o-rings were really the size they
claimed to be...

Anyway, you don't need (or want) to confine the ring 4 ways. You need
the ring to squish and seal (in the "depth" dimension), and you need to
give it room to squish (in the "width" dimension.)

All measurements are in inches. Measurements in brackets [] are -0.000,
my preferred end of the scale on these.
1/16"
width .085 + or - .003 [.082 +.006]
depth .052 + or - .002 [.050 +.004]
3/32"
width .120 + or - .003 [.117 +.006]
depth .077 + or - .003 [.074 +.006]
1/8"
width .160 + or - .003 [.157 +.006]
depth .104 + or - .003 [.101 +.006]
1/4"
width .325 + or - .003 [.322 +.006]
depth .206 + or - .005 [.201 +.010]

--
Cats, coffee, chocolate...vices to live by

PURE GOLD! Thanks, I wish I had this years ago!