Crimping

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Lug and ferrules terminals

One of the most frequent method to connect terminals/ferrules to wires is to crimp them. Insulated (automotive type), uninsulated and ferrules need different crimping tool, which are also different from the dupont crimping tool. For the mains, it is also possible to use rigid wires, which don't need ferrules. It is not normal practice for machinery, but could be ok for a machine with negligible vibrations. You may decide according local regulations for machinery.

Using crimped ferrules /sleeves

It is preferable to use crimped ferrules on stranded wires and in a lot of countries, it is compulsory for machinery.


For ferrules, you could also use the more common square crimper, search words 'HSC8 crimping'. There are also hexagonal crimp tools, like the Knipex 97 53 14: 150 euros!

Using insulated terminals

Insulated terminals 'faston' type, eyed or round terminals are crimped in two zones, one for electrical connection and the other for good locking of wire insulation. For this kind of insulated terminals, the colour is associated with wire size. It is also possible to use uninsulated terminals with thermo-retractable sleeve, but this need other kind of crimping tool. These type of terminals may not work well on small wires, so it is preferable with low cost crimp tools to use at minimum 1.5mm2 wires.

The Silverline ratchet tool PL55 is not the best quality but is more usable than the basic tool sold with terminals assortments which needs athletic capabilities. The ratchet tool may need adjustment (see the teethed wheel on the side).

'Dupont'(mini-PV), Molex-KK254 and JST-XH connectors

'Dupont'(Mini-PV) connectors (pitch 2.54 mm, rating 3A) are low cost and as the power carried in a printer is low, they could be used for anything except heating. The problem is they are quite difficult to crimp with ordinary pliers. So you need a ratchet type crimp tool and learn to use it. It is NOT recommended to solder, as this create a hard point which under stress, WILL break one day. Note that to remove a Dupont pin or plug from its shell, you need to lift the small plastic tongue locking it with a micro screwdriver. As they have no locking, it is wise to secure them with glue or tape.

Molex-KK 254 are also connectors with a pitch of 2.54mm that you can find on printer boards (Duets and Smoothieboard). Their rating is 4A and their pins are slightly bigger than 'Dupont'. They are typical in computer use. However, it is more difficult to find complete sets and cables than for other connectors. Beware the Molex-KK exists with different pitches and they are not related with PC connectors from same brand.

JST-XH connectors (rating 3A, original standard from Japan) are what you may find on Chinese clone boards and shall also be preferred to Dupont as they have a better locking and are mechanically coded. This prevent troubles. You may use the same crimping tool as for Dupont. They are used a lot in RC models, so cables, connectors and sets are easy to find.

You can use a female JST-XH or Molex-KK254 on male 'Dupont' headers, but there will be no locking. Molex-KK254 and JST-XH are completely incompatible (shape and pin size).

Note that JST 'mini'(JST-PH) have a different pitch (2mm) and are used only on plugs located on steppers (if any), so Steppers to boards cables are often JST-PH 6 pins to JST-XH 4 pins, but the pin order is not standardised throughout stepper sellers(...).

Ratchet tool SN28B, 13 euros


Wire stripper

There are miscellaneous kind of wire strippers. They guaranty good work with no cutted strand. The model shown on photo is not the most common but fairly practical as it automatically adjust to the wire size.

Face automatic wire stripper Jokari 20050, 22 Euros


See also

External links

Youtube: Video of bootlace ferrule crimping Tech Matt Millman: Very detailed page about small connectors


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