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How Do You Crimp A Ferrule?
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mikerj:
I thought the whole point of a ferrule was to prevent a screw terminal cutting into the copper strands?  A ferrule placed into a screw terminal is placed under pressure by the terminal itself, so not sure it's quite the same as a normal crimp.
floobydust:
Ferrules are used to keep all strands together, because some would splay out and short to adjacent terminals. It depends on how skilled the people are doing the panel wiring, most don't even notice loose stands :palm:

For screw terminals, a fork crimp-connector is used. A ferrule ends up getting pinched under one side of the screw which does not stay tight and they fall out.

I don't see ferrules used as much in North America. People go straight with stranded wire into a DIN-rail terminal block because the ferrules are extra labour and cost, but don't offer anything when mated with a sliding cage-clamp terminal block.

After seeing aluminum ferrules and some cheap ones very thin metal, I decided they are just another failure mechanism, unless they are a good brand matched with the right crimping tool, and right for the wire size.
dom0:
I usually use a Knipex  97 78 180... it works. The degree of deformation seems pretty high but I've never had issues with it. In German this style is called Dornverpressung, I won't attempt to translate.

For bigger cable shoes (16 mm²) I've borrowed a Klauke tool in the past, it looks like a big bolt cutter. It doesn't look like it's making much of a (hexagonal by way of two identical forming dice) dent in the ferrule part of the cable shoe, until you try pulling the cable out, which is positively not possible.

Looks can be deceiving.


--- Quote from: thm_w on November 01, 2019, 10:37:42 pm ---
--- Quote from: SparkyFX on November 01, 2019, 10:36:23 pm ---I don´t think the shape matters that much in the moment you clamp them down with a screw/contact in the contact they are meant to end in. Some clamping mechanisms might work better with a flat shape or no ferrule at all.

--- End quote ---

Square will let you use the largest size wire possible to fit in a square screw terminal. I would also think contact area would be largest, but would depend if the screw force is enough to deform the crimp into another shape.

--- End quote ---

I've used the front-insert Knipex square crimping tool with cage lift clamps, and looked at the markings the clamp left on the crimped ferrule. It doesn't look like the cage lift clamp can muster enough clamping force to deform the ribbonized flat surface into uniform contact.
bluey:

--- Quote from: Brutte on November 01, 2019, 08:56:55 pm ---I do not think the ferrules are air-tight to the extent the crimped connectors are.

--- End quote ---

Weidmuller says: "ferrules, applied with the proper crimping tool, form a gas-tight*
connection shielding the wire from corrosion even in a salty environment."

https://www.weidmuller.com/bausteine.net/f/7862/Weidmuller_Ferrules_White_Paper.pdf

I got a cheap clone of the Knipex 97 53 14,  side load ferrule crimper from Aliexpress, for about 1/5 of the price of a Knipex, for occasional hobby use. It looks fairly well designed, made and packaged. It is adjustable, but there is no guidance on how one should adjust it if at all. The Knipex/Rennsteig square ferrule crimper has 2 preset settings, one for small and one for large. The hex crimper is unadjustable.

Because the tool has multipoint jaws rather than flat jaws, the gas tight parts would be multiple along the ferrule length but not visible at the end.

http://www.fse-tool.com/en/product/?11_248.html
https://www.knipex.com/index.php?id=1216&L=1&page=group_detail&parentID=&groupID=1307
https://www.rennsteig.com/en/products/crimping/198-ferrule-crimping-tool-pew-8-184-8-185-8-186

Anyone got any clues?


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