Is there a standard catalog of rectangular cross-section O-rings?
It's a hot-water application, in fact the group gasket for an old
espresso machine.
Is there a standard catalog of rectangular cross-section O-rings?
It's a hot-water application, in fact the group gasket for an old
espresso machine.
The dimensions need to be about 2 1/4" OD, 1 7/8" ID but a little
over 1/4" thick, say 5/16". The thickness is the sticking point.
Long ago I machined a teflon ring for the job, but to my supreme regret
I damaged it on removal and the only remaining stock on hand is .250"
thick. That's not quite enough.
McMaster sells 3/8" sheets, but the smallest piece is six by six inches,
$60 and lots of work. To my surprise there's nothing on Amazon. Tap does
not list teflon at all. Back in the day I just went to Abe Schuster Plastics >in Oakland CA and bought a bit of scrap 8-)
It's possible a round-section Buna O-ring could be crammed into the groove >but it looks like Parker does not make one that comes close (too skinny)
and the curved cross section will promote un-centering of the gland.
Another option is to use the too-thin teflon and put a slim backing
o-ring under it, Parker 2-034 or 2-137.
Writing this helped collect my thoughts, if you have anything to add
please do.
On Mon, 24 Apr 2023 15:51:41 -0000 (UTC), bob prohaska
<bp@www.zefox.net> wrote:
Is there a standard catalog of rectangular cross-section O-rings?
It's a hot-water application, in fact the group gasket for an old
espresso machine.
The dimensions need to be about 2 1/4" OD, 1 7/8" ID but a little
over 1/4" thick, say 5/16". The thickness is the sticking point.
The dimensions may well be metric.
Would a Parker X-Ring Seal work?
.<https://www.parker.com/literature/O-Ring%20Division%20Literature/Bulletin%20pdf's/xring.pdf>
On Mon, 24 Apr 2023 15:51:41 -0000 (UTC)
bob prohaska <bp@www.zefox.net> wrote:
<snip>
Is there a standard catalog of rectangular cross-section O-rings?
It's a hot-water application, in fact the group gasket for an old
espresso machine.
Probably already checked but...
Any chance this Expresso parts place has something close enough?
https://www.espressoparts.com/collections/browse-common-espresso-machine-parts-group-gaskets
"bob prohaska" wrote in message news:u268id$db84$1@dont-email.me...
Is there a standard catalog of rectangular cross-section O-rings?
It's a hot-water application, in fact the group gasket for an old
espresso machine.
The dimensions need to be about 2 1/4" OD, 1 7/8" ID but a little
over 1/4" thick, say 5/16". The thickness is the sticking point.
------------------
Disk brake calipers have similar seals, though selecting them by size
instead of vehicle might be difficult.
When I couldn't find the exact OD, ID and length for a hydraulic cylinder seal I machined a spacer to adapt the closest match.
Jim Wilkins <muratlanne@gmail.com> wrote:
"bob prohaska" wrote in message news:u268id$db84$1@dont-email.me...
Is there a standard catalog of rectangular cross-section O-rings?
It's a hot-water application, in fact the group gasket for an old
espresso machine.
The dimensions need to be about 2 1/4" OD, 1 7/8" ID but a little
over 1/4" thick, say 5/16". The thickness is the sticking point.
------------------
Disk brake calipers have similar seals, though selecting them by size
instead of vehicle might be difficult.
I didn't think of brake parts. The seals won't be food-grade, but anything >that can withstand hot brake fluid is likely to be pretty inert 8-)
It turns out O'Reilly's Auto lists replacement pistons by OD,
the sizes step from 57.7 to 59.2 mm. If the photo is any guide,
the seals are much too skinny, but it might be worth a visit.
When I couldn't find the exact OD, ID and length for a hydraulic cylinder
seal I machined a spacer to adapt the closest match.
That's sort of where I am now. I use the Teflon for structure and add an >o-ring groove on the rear face in order to obtain the overall thickness.
On Mon, 24 Apr 2023 20:21:44 -0000 (UTC), bob prohaska
<bp@www.zefox.net> wrote:
Jim Wilkins <muratlanne@gmail.com> wrote:
"bob prohaska" wrote in message news:u268id$db84$1@dont-email.me...
Is there a standard catalog of rectangular cross-section O-rings?
It's a hot-water application, in fact the group gasket for an old
espresso machine.
The dimensions need to be about 2 1/4" OD, 1 7/8" ID but a little
over 1/4" thick, say 5/16". The thickness is the sticking point.
------------------
Disk brake calipers have similar seals, though selecting them by size
instead of vehicle might be difficult.
I didn't think of brake parts. The seals won't be food-grade, but anything >>that can withstand hot brake fluid is likely to be pretty inert 8-)
It turns out O'Reilly's Auto lists replacement pistons by OD,
the sizes step from 57.7 to 59.2 mm. If the photo is any guide,
the seals are much too skinny, but it might be worth a visit.
When I couldn't find the exact OD, ID and length for a hydraulic cylinder >>> seal I machined a spacer to adapt the closest match.
That's sort of where I am now. I use the Teflon for structure and add an >>o-ring groove on the rear face in order to obtain the overall thickness.
Why not just machine the whole seal from solid Teflon, starting with
solid Teflon? It may be the cheapest way, unless one can find the
expresso maker.
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