Forming wire mesh cloth - how to compress a cylindrical shape?

I'm forming some wire mesh cloth - that part is going ok.
The finished part needs to be compressed to fit into a pvc part - working it
in by hand results in scratching and marking of the pvc. I'm looking for some ideas on how to compress the mesh part so it slips cleanly into the pvc part. There's a few pics in the dropbox:
http://www.metalworking.com/dropbox/wire_screen.pdf
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On Mon, 8 Feb 2010 21:07:21 +0800, the renowned "Royston Vasey"

Stuff it into a stubby thin-walled open-ended tube (maybe with a ring or other handle at one end) shove the tube into the PVC and then withdraw the tube while pushing against the top of the screen so it stays seated in the PVC.
(Sort of how I imagine how a tampon applicator would work).
Best regards, Spehro Pefhany
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Info for manufacturers:

Yeah, I toyed with that idea - like some of the old piston ring compressor sleeves for auto engines. The open end needs to be squeezed a little smaller than 16mm OD but the flat top end OD is fixed at 16mm and wouldn't fit through.
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Royston Vasey wrote:

Do you *any* leeway here? If the flat top end could be 14mm, say, it would work nicely. The forming bar & die could be tapered & would work better than the straight ones.
Bob
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Sure it will Roy...
Make the "sleeve" out of multiple petals of thin sheet stock. Push the screen home, then slide out the shims one at a time.
LLoyd
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On Mon, 08 Feb 2010 08:25:11 -0500, the infamous Spehro Pefhany

Great minds think alike, Pete. <g>
-- We don't receive wisdom; we must discover it for ourselves after a journey that no one can take for us or spare us. -- Marcel Proust
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Could you hold it on the outside of the PVC with a press-on stainless sleeve? Maybe cut a groove and wind wire around the screen to squeeze it in, then press the sleeve on to cover and secure the sharp ends. Or perhaps you can find a stainless key ring the right size.
A retaining sleeve on the inside could split the pipe.
If it really has to be inside maybe you could fold the rim back over itself over a tube mandrel before cutting it so it would snap into an internal groove.
jsw
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wrote:

Could you hold it on the outside of the PVC with a press-on stainless sleeve? Maybe cut a groove and wind wire around the screen to squeeze it in, then press the sleeve on to cover and secure the sharp ends. Or perhaps you can find a stainless key ring the right size.
A retaining sleeve on the inside could split the pipe.
If it really has to be inside maybe you could fold the rim back over itself over a tube mandrel before cutting it so it would snap into an internal groove.
jsw
You've given me an idea Jim, maybe I should "trepan" a slot into the end of the PVC, fill it with urethan and just push the screen into the urethane. Cheers. _________ |_ /------ _] | | | ---> | |_ \------ _] |_________
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That's how the hydraulic tank pickup filters that Northern sells are assembled. I know because I had to glue one back together.
jsw
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My thought would be to compress it around a mandrel. My first thought was using a ratcheting cargo strap, but chucking the mandrel in the lathe and wrapping rope around it might work well. Sort of how one makes springs on a lathe using something in the tool post to control the tension in the rope. Still another idea would be using something like a single wheel knurling tool to force the wire against the mandrel.
Dan
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wrote:

My thought would be to compress it around a mandrel. My first thought was using a ratcheting cargo strap, but chucking the mandrel in the lathe and wrapping rope around it might work well. Sort of how one makes springs on a lathe using something in the tool post to control the tension in the rope. Still another idea would be using something like a single wheel knurling tool to force the wire against the mandrel.
Dan
Mmm, thanks Dan, its only 16mm ( 5/8") in size - your approach is what I'd thought of if it was bigger - kind of like a mini strap wrench or band style ring compressor.
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Royston Vasey wrote:

Here's an idea if you don't need to do many in a hurry. Make a recess in a block of suitable material, maybe 15.5mm in diameter, and suitably deep. Have it split down the middle. Place the wire form in to compress it then fill the recess with water and freeze it. When frozen remove the former and drop the wire form and ice slug into your PVC part and allow the water to thaw.
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Neat - no good for me but its a good idea.
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On 2/8/2010 8:07 AM, Royston Vasey wrote:

Tighten a hose clamp around it.
Kevin Gallimore
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A bit too big - gives me the idea of a small cable tie maybe.
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One approach is to fix the wide end by electroplating, so it doesn't expand when removed from the mandrel. Keeping a mesh in shape this way is a standard tactic (among makers of electron lenses for scanning electron microscopes, anyhow).
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What's that Lassie? You say that Royston Vasey fell down the old rec.crafts.metalworking mine and will die if we don't mount a rescue by Mon, 8 Feb 2010 21:07:21 +0800:

If the PVC piece is bored through, I would try using a piece of cloth. Push the piece of cloth part way through, then put the screen part in place. Pull the cloth from the other end, and it should drag the screen with it. When in place, hold back on the screen part, and continue pulling the cloth out. A hole in the cloth would allow a bar to push against the inside end of the screen part, holding it in place.
--

Dan H.
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On Mon, 8 Feb 2010 21:07:21 +0800, the infamous "Royston Vasey"

Think "tampons", Royston. <vbg> How about a teflon sleeve with an OD the size of the ID of the PVC to help guide the screen in?
Or a pair of spring steel guides on sticks, curved tongs if you will.
Questions: Do you later "inflate" the cup back to full inside diameter? What do you use to secure it to the PVC? And, last but not least, whatever are these used for?
Another thought: If you were to compress the cup closer to final diameter, it might be easier to work with. It appears to have lots of gaps between the folds and OD.
-- We don't receive wisdom; we must discover it for ourselves after a journey that no one can take for us or spare us. -- Marcel Proust
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scrawled the following:

ing steel guides on sticks, curved tongs if you will.

Everytime I think tampons I'm reminded of UK's Prince Charles bugged phone call where he told I think it was Camilla Gorilla his bit on the side at the time that he "wished he was her tampon" - a nasty thought! :|
The tongs is a good idea - I just made something similar using some crimpers:
http://www.metalworking.com/dropbox/wire_screen_tool.pdf
Once in place the screen springs back quite a bit, I still need some urethane - maybe sika 191, 293 ?? The black marine stuff anyway, that works really well on most things. The screen is a shield over a humidity sensor - to stop fingers and look nice more than anything else. I don't think there is a way to eliminate the folds and extra mesh / cloth. The cloth doesn't want to stretch enough so a degree of folding results.
cheers.
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On Tue, 9 Feb 2010 11:45:46 +0800, the infamous "Royston Vasey"

Heh heh heh.

Ah, good!

Have you tried a press in the shape of those tongs? Place screen cup over mandrel and compress vigorously with tons of force to 'set' the folds tighter.
Alternatively, have you thought of just using a disc of screen and a slightly longer piece of PVC, dadoing in the flat screen piece? You could even use a heftier screen gauge to keep fingers from damaging it.
-- We don't receive wisdom; we must discover it for ourselves after a journey that no one can take for us or spare us. -- Marcel Proust
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