How Do You Crimp A Ferrule?

[German_EE]

No, this isn't a trick question. For years I have been crimping ferrules using a hand held tool that squashes them flat without using a ratchet and I've never seen a failure. Tonight I sat in a workshop whilst someone used a ratchet-based tool that gave a hexagon shaped crimp similar to what you get at the cable end of a BNC plug only smaller.

He claimed that the hexagon crimp produced less stress on the strands but I thought the whole idea of crimping WAS stress, clamping down hard enough for a gas-tight connection?

Thoughts?

[Brutte]

I do not think the ferrules are air-tight to the extent the crimped connectors are. The ferrules are more used to organize the strands in more managable way. Then you squeeze the ferrule in a terminator anyway.

My tool crimps on four sides. It has a ratchet mechanism.
No problem with that, except when I ordered tinned copper ferrules from eBay that had no copper. Or at least not much.

[reboots]

I use this 4-sided ratcheting crimper:

https://www.wagoproducts.com/tools/series-206/wago-206-204/

There are cheaper 4- and 6-sided crimpers on eBay.

I suspect a flat crimp would place the wire strands in the middle under excessive stress, and the strands on the edges under insufficient stress. I believe the ideal ferrule geometry will gather the strands firmly together in their manufactured "lay".

[floobydust]

I worked for a utility company that exclusively used 4 (square) ferrule crimps for all wiring.
I bought a Weidmuller hex crimper and they flipped out and demanded I not use it. Phoenix Contact's tool was also double the price.

Apparently the square 4 crimp has a bigger flat portion, so screw terminals/ sliding cage clamps on DIN-rail stuff contacts it better. The hex is rounded more and not as good.

There are aluminium or tin-plated copper ferrules, of varying thickness and quality, to watch out for.

[tautech]

No, this isn't a trick question. For years I have been crimping ferrules using a hand held tool that squashes them flat without using a ratchet and I've never seen a failure. Tonight I sat in a workshop whilst someone used a ratchet-based tool that gave a hexagon shaped crimp similar to what you get at the cable end of a BNC plug only smaller.

He claimed that the hexagon crimp produced less stress on the strands but I thought the whole idea of crimping WAS stress, clamping down hard enough for a gas-tight connection?

Thoughts?

A crimp is essentially a cold pressure weld, get it wrong and the cable can be compromised.
Single point crimps can over-stress the conducting strands however if the crimping system is properly matched problems are rare.

[rvalente]

For years i've used weidmuller or burndy rachet crimping tools works like charm.

Once I saw this hexagon crimping found is amazing because one tool to crimp from .5mm to 4mm and very easy to use. After some tests I regretted buiying, total piece of crap. Loosen connection, useless.

Keep your trusty weidmuller

[SparkyFX]

He claimed that the hexagon crimp produced less stress on the strands but I thought the whole idea of crimping WAS stress, clamping down hard enough for a gas-tight connection?

The purpose of the crimp is a cold weld of the strands. The non-crimped part rearranges the strands to get from round to the final crimp shape, as it would when bending them together with insulation along a radius.

In theory a hexagonal crimp should be less of a stress riser to the edge of the ferrule, but the way these are created makes me doubt about that, as they almost fold over the edges.

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.

[thm_w]

For years i've used weidmuller or burndy rachet crimping tools works like charm.

Once I saw this hexagon crimping found is amazing because one tool to crimp from .5mm to 4mm and very easy to use. After some tests I regretted buiying, total piece of crap. Loosen connection, useless.

Keep your trusty weidmuller

Not sure what you are trying to say as Weidmuller makes a hex crimper rated from 0.14mm² to 10mm²: https://catalog.weidmueller.com/catalog/Start.do?localeId=en&ObjectID=(%5b1445070000%5d)
Maybe yours was defective or not adjusted to the proper tension.

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.

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.

[tooki]

I worked for a utility company that exclusively used 4 (square) ferrule crimps for all wiring.
I bought a Weidmuller hex crimper and they flipped out and demanded I not use it. Phoenix Contact's tool was also double the price.

Apparently the square 4 crimp has a bigger flat portion, so screw terminals/ sliding cage clamps on DIN-rail stuff contacts it better. The hex is rounded more and not as good.

There are aluminium or tin-plated copper ferrules, of varying thickness and quality, to watch out for.

I think I read somewhere (after buying a cheap hex ferrule crimper at the ’bay) that you want to match the crimp shape to the terminal shape. So for terminals with flat contact surfaces, square crimps, and for terminals with round contact surfaces (like drilled holes with set screws, e.g. in many banana connectors), the hex is a better match.

[Neomys Sapiens]

Basically all said. Except there are a lot of ratcheting square crimpers that do it from one side only - they do not cut the mustard. Weidmuellers PZ4 falls into this category, as do most look-alikes.

The symmetrical acting side crimpers (like the Wago mentioned) are ok, as is the Weidmüller PZ3 (front entry).

[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

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.

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.

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.

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]

I do not think the ferrules are air-tight to the extent the crimped connectors are.

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?