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Square or hex ferrule crimper

Updated: 21 October 2026

You already know the cable is 2.5 mm², or 10 mm², and the open question is the jaw. A square or hex ferrule crimper changes the outline of the bootlace before it enters the terminal. It does not, on the evidence in this set, change a measured resistance, and it does not make the joint gas-tight because a seller used that word. Four jaws, six jaws, or the Knipex half-round nests are three different tools. Prices and review counts stay on the [ferrule pliers comparison](/hub/pliers/ferrule-pliers). Listing text, UK review notes and public crimp guidance were compared on 19 October 2026. We did not section a crimp in a lab.

You already know the cable is 2.5 mm², or 10 mm², and the open question is the jaw. A square or hex ferrule crimper changes the outline of the bootlace before it enters the terminal.

Our top picks

KNIPEX Knipex ferrule pliers 97 72 180

Best overall

KNIPEX Knipex ferrule pliers 97 72 180
9.8/10about £35.96
View offer
Preciva Preciva square ferrule kit CP621200

Best value

Preciva Preciva square ferrule kit CP621200
9.6/10about £22.99
View offer
WEICON Weicon hex ferrule pliers 10100513

Alternative

WEICON Weicon hex ferrule pliers 10100513
9.2/10about £85.99
View offer
On this page
  1. 1.What square and hex actually change
  2. 2.Round hole or cage clamp
  3. 3.Marked half-round dies
  4. 4.When the listing is silent

What square and hex actually change

Square, in the tools that name it, is a four-jaw squeeze. The Preciva CP621200 states a uniform square crimp for 0.25–10 mm². The AivaToba HSC8-6-4A states a four-jaw square ratchet, with the title at 0.25–10 mm² and the size line at 0.5–10 mm². You see four flats on the metal tube. Hex is six jaws. In this set that is the AivaToba YXQ008-16, the YXQ008-16-NEW, the DxCRIMP up to 25 mm², and the Weicon 10100513 for 0.5–16 mm². UK reviewers of the YXQ008-16 prefer the six-sided crimp for smaller holes. That is their preference, not a resistance test. WAGO’s FAQ says fit, strip length and conductor diameter matter more than the outline, and that “gas-tight” has no single definition.

Round hole or cage clamp

Choose hex when the terminal is a round tunnel. The Weicon sheet for 10100513 puts the hex crimp there, to ease entry into round terminals. If that hex tool will not open around your ferrule, the packet shape does not help. Choose square when the landing is a cage clamp and you want four flats. The Preciva CP621200 and the AivaToba HSC8-6-4A are the named square tools here for flex up to about 10 mm². If any ferrule is a struggle, the fix is strip length and diameter. A six-side title does not help if the jaw will not open. Reviews of the AivaToba YXQ008-16-NEW say 10 mm² and 16 mm² do not spring into the jaws. Those capacity limits belong on the ferrule crimping tool buying guide.
KNIPEX Knipex ferrule pliers 97 72 180

Testsieger

KNIPEX Knipex ferrule pliers 97 72 180
9.8/10about £35.96
View offer

Marked half-round dies

The Knipex 97 72 180 is neither of those self-adjusting shapes. It has nine half-round dies from 0.25 to 16 mm², cited to DIN 46228 parts 1 and 4. You pick the nest. There is no ratchet stated. One review says the wires pull out. The crimp is that die’s form, not a four-flat square and not a six-flat hex. Buy the Knipex when the drawing names the mm² and you buy ferrules separately. Leave it when you wanted a ratchet kit. The squeeze itself is on how to crimp a bootlace ferrule. For ordinary domestic flex, one profile that enters the terminal is enough.

When the listing is silent

Two tools never say square or hex. The Preciva at £23.99, with dual ferrules claimed, describes a ratchet and a pressure adjuster and then stops. The Flintronic at £9.99 prints AWG 23–7 and no profile. The Holy Feather still does not say square or hex, and it has no reviews. If the terminal needs a known outline, buy a listing that names it. Take one ferrule of the size you will use, offer it to the terminal, and see whether a square or a hex sleeve is the one that enters. No listing here has a published contact-resistance figure that would overturn that check.

Common questions

Is hex a better electrical connection than square?
Not on any measurement in this set. Hex leaves six flats and sits nearer a circle. Square leaves four flats. Weidmüller says the better outline is the one that matches the compartment, and WAGO says fit, strip length and conductor diameter matter more than the outline. A seller’s “gas-tight” line is not a defined test. WAGO notes that the phrase has no single meaning.
Which shape enters a round tunnel more easily?
Hex is the shape makers and forum comments associate with a round hole, because it is closer to round than four flats. The Weicon sheet says the hex crimp is there to ease entry into round terminals. A tight screw will still squash the sleeve afterwards. If a particular hex tool will not open around a 16 mm² ferrule, the shape on the packet does not help.
Which shape suits a cage clamp?
Square is the usual match when the compartment is square and you want four flats against the cage. That is why the named square ratchets in this set, the Preciva CP621200 and the AivaToba HSC8-6-4A, are the first look for cage-clamp flex up to 10 mm². If the ferrule is the wrong mm², neither profile repairs the fit.
What are the Knipex half-round dies if they are neither square nor hex?
They are nine marked nests on the 97 72 180, from 0.25 to 16 mm², cited to DIN 46228 parts 1 and 4. You select the size and close that die. There is no self-adjusting ratchet. The result is a half-round mandrel crimp, not a four-jaw square and not a six-jaw hex. The tool is sold without ferrules.
Does a six-side tool that will not open at 16 mm² still count as the hex choice?
It counts as a hex tool for the sizes that enter and release. The AivaToba YXQ008-16-NEW is hexagonal on the listing, and UK reviews say 10 mm² and 16 mm² do not spring into the jaws. For those conductors it is not a working hex choice until the ferrule goes in and comes out. Check with one sleeve before you strip a loom.

Related pages

Best ferrule crimping pliers

Ferrule pliers

Bootlace ferrule sizes: match the mm², then colour

Ferrule crimping tool buying guide: range, jaw, kit

How to crimp a bootlace ferrule: strip, squeeze, pull

Sources

Public UK sources from the research digest, last checked on 19 October 2026. Shelf prices and star lines are the amazon.co.uk figures in the display file. The price bands are this set, not a market average.

  1. IET Wiring Matters: terminal blocks and regulation 526.9 (retrieved 19 October 2026)
  2. GOV.UK: building work, replacements and repairs (retrieved 19 October 2026)
  3. IET: Part P FAQ for England and Wales (retrieved 19 October 2026)
  4. Electricity at Work Regulations 1989 (retrieved 19 October 2026)
  5. Knipex 97 72 180 product page (retrieved 19 October 2026)
  6. Weicon 10100513 data sheet (retrieved 19 October 2026)
  7. RS Online: crimp tools guide (retrieved 19 October 2026)
  8. Termnex: bootlace ferrule colour codes (retrieved 19 October 2026)