Screen Mesh

Could someone tell me the definition of a screen's mesh? I am working on a project that calls for #4 mesh screen. The local hardware has some screen
but it is unmarked and neither of us knows how to measure it.
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On Sat, 05 Feb 2005 02:54:31 GMT, the renowned "Terry Mayhugh"

What these guys call 4 mesh has 4 squares to the inch. The material and the size of the wires are other variables.
http://www.meshphoto.com/brass/004X004B047.html http://www.meshphoto.com/copper/004X004C030.html http://www.meshphoto.com/galvanized/004X004G035.html http://www.meshphoto.com/welded/004X004W032.html
Best regards, Spehro Pefhany
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Thanks!
Info for manufacturers: http://www.trexon.com

http://www.speff.com
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Terry Mayhugh wrote:

Sounds like a riddle in the making.
--
Gary Brady
Austin, TX
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Yep ...

a
screen
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I like #8 (1/8") screen, myself. Not quite too fine to not work well (like window screen, for instance).
Tim
-- "I've got more trophies than Wayne Gretsky and the Pope combined!" - Homer Simpson Website @ http://webpages.charter.net/dawill/tmoranwms
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#4 mesh screen is nominally 1/4" square [4/in.] The opening dimension is determined by the size of the wire it's made from. Brass screens for soil testing are made from 1-1/2" opening to 200 mesh. You can get the ASTM specifications from most any civil engineering company. On the other hand, ordinary 1/4" rabbit wire from the local hardware store may be all you need. Bugs
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Bugs wrote:

The specs for brass testing sieves are printed in the McMaster-Carr catalog. You can get them online by viewing page 347. You can try clicking on: http://www.mcmaster.com/ctlg/DisplCtlgPage.asp?ReqTypTALOG&CtlgPgNbr47
GWE
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Terry Mayhugh wrote:

Some people have crossed references here so I had to butt in:
4 mesh is not the same as 1/4" screen. 4 mesh is 4 full openings per inch as measured between parallel wires, perpendicular to the wire faces, center to center of wires. 1/4" opening is a CLEAR opening as measured the same way except ignoring the wire.
On each, the gauge of the wire should be specified also. For example, a 1/4" opening fabricated from 14 gauge wire (.080") would actually be a (nominal) 3 mesh.
It gets a little anal but you do have to measure between PARALLEL wires, perpendicular to the wire face. Some meshes are parallelograms rather than square so instead of measuring along the length or width relative to the edges of the screen, you do need to specify wire to wire.
The "perpendicular to parallel wires" thing doesn't come up much in hardware cloth type screens but becomes true all the time in chain link material (like fencing). In case you haven't noticed, chain link fence is NOT the same as when we oldsters were kids. One of the first cheats was to change from 6 mesh to 2" opening. Back in the days when chain link wire was a little heavier, this made some manufacturers appear cheaper as the opening was just a fraction larger so there was less material, fewer overall spirals to make on a large run, and fewer loops in each spiral. Of course chain link fencing is now made with HUGE openings and tiny wire to make it cheap as dirt.
It also comes up on security fencing where the openings are to be quite small. You can't get a finger in 1/2" mesh but you might be able to in 1/2" opening
Koz (who rambled to kill a little time)
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a
You made it way too complicated. 4-mesh means four wires per inch, PERIOD. If you want 1/4" openings, you specify 1/4" SPACE CLOTH.
There certainly are other things that can complicate it, like different wire sizes, predominance of metal vs. openings in fine meshes, etc.
But simply said, if the spec calls out "Mesh size", it means "wires per inch". If it calls out OPENING size, you can do the math, or just order "space cloth".
LLoyd
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