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Frank, Good description, While I acknowledge that many O’ring manuals have
differing dimensions I put some things such as bottom radius as nice to have
but the squeeze, surface finish, clearance and breaking of edges as necessary.
As you say it is a simple design that works well. Parker does a good
manual. Chs Hugh From:
owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org] On Behalf Of ShellyDalg@aol.com Hi Brent. The groove for an "O" ring is quite a bit
wider than the "O" ring itself, leaving a space inside the
groove for water to get into. The "taper" in the groove is on the
inside face and it's only a tiny bit, under 5 degrees out of plumb. The bottom
corners of the groove are supposed to be rounded slightly. The Parker
"O" ring "design book" explains the function and has charts
for sizes and many different types of applications depending on what the
"O" ring is trying to accomplish. There's quite a few different types
of groove shapes with some designs based on a rotating shaft, sliding shaft,
and a bunch of other applications. The common function of all of them is to
apply pressure against the rubber and force it into a TINY crack. The "O" ring gets pushed up against the inside groove
wall as the water pressure is applied. The "O" ring doesn't
really deform into a slightly rectangular shape until the pressure builds up
enough to squash the hatch down. The groove needs to be wide enough to accommodate the
"squared" "O" ring and still leave enough space for the
water to get in there so the water is applying pressure to the "O"
ring, forcing it up against the crack between the two metal surfaces. It's a
real simple design and can withstand a LOT of pressure. Your rendering shows the taper on the outside groove wall and the
rubber "O" ring is filling the groove. That won't seal because
there's no where for the water to get in there so it's actually acting like a
flat gasket. The water would slip under the squared "O" ring because
the pressure is being applied to the gap and not "behind" the
"O" ring. Frank D.
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