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Crimping versus soldering, in avionics

Back to crimping an crimping tools…

Is every red/blue/yellow tool standard? I have the one below – quite pricey – and it doesn’t compress the terminals far enough.

Yet, the jaws on it close right up where shown by the arrows, so it is not a matter of adjustment.

Administrator
Shoreham EGKA, United Kingdom

Peter wrote:

Also compliant pin will still work loose eventually if you shake it hard enough and the connector is not well secured altogether

It lasts longer than a soldered joint in a PCB

Darley Moor, Gamston (UK)

Here is another crimping tool with the same colour codes

But that one has wire gauges printed on it…

Is every “red” tool suitable for every “red” crimp terminal – subject only to the terminal having a wire inserted into it which is within the terminal’s specific gauge range (e.g. 14awg to 10awg)?

Administrator
Shoreham EGKA, United Kingdom

And here is another – this one is Chinese German so should be perfect

They all have slightly differently shaped jaws

Administrator
Shoreham EGKA, United Kingdom
I never use this type of connectors, anywhere, I think they are unsafe. Instead I only choose the bare type and some heatshrink, and solder them in times. So the crimping tool will be like that:

https://www.ebay.de/itm/ADELID-Crimpzange-fur-unisolierte-Kabelschuhe-von-0-5-bis-6mm-Quetschzange/281901497344

Vic
vic
EDME

I agree 100%; I think they are crap. But planes are full of them. Not just French (that pic is from my TB20) but American too.

And the inline splices widely used in avionics are also insulated

The problem with soldering on say the terminals of a circuit breaker is that there is no way to support the wire. So crimping is better than soldering.

Administrator
Shoreham EGKA, United Kingdom

Peter wrote:

Back to crimping an crimping tools…

Is every red/blue/yellow tool standard? I have the one below – quite pricey – and it doesn’t compress the terminals far enough

The more standard ‘Aviation’ tools are those made by AMP. There are separate red, blue and yellow tools, denoted by the coloured sleeves on the handles. These tools have an adjustable jaw for the insulation barrel. The adjustment is normally a pin in one of three holes for each half of the jaw, or alternatively a stepped cam with a screwdriver slot. Both are shown in the picture, and in the case of the red handled set, I have locked them in the tightest grip position for modern thin-wall cables by using a screw and nut.

Also worthy of note is that there are many version of the PIDG crimp (it stands for Pre-Insulated Diamond Grip). AMP versions as normally found on aircraft have a welded barrel for the conductor crimp and a separate metal barrel for the insulation crimp. Commercial versions just tend to have a rolled but not solid conductor crimp crimp, and the coloured plastic barrel crimps straight onto the conductor insulation.

Last Edited by wigglyamp at 10 Jan 18:59
Avionics geek.
Fairoaks. EGTF

How do you know you have made a solid joint?

I have just tried pulling some wire out. From the PIDG it pulls out, although it does take a lot of force. From the non-insulated crimp terminal referenced by Vic above, the wire breaks before it comes out; that one is definitely stronger, as well as visually more “obvious”.

Interesting regarding the welded barrel. One can buy the terminals from 2 pence to 50 pence for apparently the same item. I wonder if it makes a difference. As it turns out I have both types here and I can’t see any difference in the way the terminal tube deforms over the wire, with a given crimp tool.

However I tried another PIDG terminal, same internal wire aperture, same wire, same tool, and the wire came straight out. I have the feeling that if I can achieve this, so can others.

Administrator
Shoreham EGKA, United Kingdom

With the AMP tools, the standard pull-off test is to set the insulation barrel to the widest setting so it doesn’t grip, and then make off a crimp on the wire barrel. You then bend the wire 90 degrees to the terminal and ensure it doesn’t come out. If that’s OK, then reset the insulation adjustment and proceed to crimp.

Are you definitely getting the crimp the right way around in the tool, so the correct jaw is crimping the wire barrel? From your picture in Post #34. the wire barrel is the one with the numbers on the jaw face and the insulation barrel is against the coloured dots (Sorry not trying to teach granny to suck eggs but not every one will know this).

I also have a multi-purpose tool from RS as you’ve shown above and that also works very well on the wire barrel down to 24 AWG but is slightly loose on the insulation crimp on wires below 20 AWG

Avionics geek.
Fairoaks. EGTF

Yeah, I had the tool backwards…

Now it works great. Cannot pull the wire out at all.

However I can’t say it does much for gripping the insulation.

(the actual wire is mangled in the above one; that was just a test for whether the insulated part of the wire gets gripped)

Notwithstanding the above cockup, this is somewhat curious because I have done loads of crimps in the past on the ultra pricey (£2/pin) Positronic connectors (usually Positronic versions of the standard DB connectors) and some other stuff involving thermocouple wire (which mostly can’t really be soldered) and those worked great. But I have the proper tool for those (ex Ebay but otherwise about £600)

Looking at these crimps (original Socata work) it’s obvious that there is no grip at all on the insulated portion. It just flops around. There is a little compression of the metal cylinder there but not enough.

Administrator
Shoreham EGKA, United Kingdom
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