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Gizmo

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Joined: 05/06/2004
Location: Australia
Posts: 5078

Posted: 02:57pm 26 Jan 2016

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Recently I needed to make up some new battery cables using 35mm square cable and lugs. These lugs need to be crimped, and should then be soldered. Soldering isn't enough, its the crimp that retains the cable in the lug if the connection gets hot enough to melt the solder.

I dont have a crimping tool to suit the lugs. I could just squash the lug onto the cable with a vise or hammer, but it looks yuk. A pin or center punch gives a better result, but the lug is still flattened and still looks yuk.

So I made a jig from a piece of hardwood. You could use any hard material, like aluminium or steel. A hole was drilled in the hardwood to be a tight fit over the lug, then I cut out a slot to the hole. The idea of the tight fitting hole is the lug will retain its shape. The pin was made from a piece of rusty 6mm steel rod. Its has a rounded end.

Once the lug and cable are in place, I just hammer the pin to create a nice tight crimp. Then the lug is soldered and finished with some heat shrink.

Glenn

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greybeard
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Joined: 04/01/2010
Location: Australia
Posts: 161

Posted: 03:23pm 26 Jan 2016

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I like the use of a 'rusty' steel rod, nice touch

Great idea though.

redrok

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Joined: 15/09/2014
Location: United States
Posts: 209

Posted: 11:14am 08 Mar 2016

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Hi Gizmo;

Gizmo said Recently I needed to make up some new battery cables using 35mm square cable and lugs. These lugs need to be crimped, and should then be soldered. Soldering isn't enough, its the crimp that retains the cable in the lug if the connection gets hot enough to melt the solder.
Glenn

I would not use a "Punch" like tool to do the crimping. My preferred tool is more like a "Wedge". A very dull wedge with a rounded edge of about 1/8th inch. This forms a line lengthwise along the barrel.

Technically, a good crimp produces a true pressure weld. This is nearly the lowest resistance connection. Then add the solder. The solder adds a gas tight seal against moisture and acid. And yes, will slightly reduce the resistance.

On a side note, if you look in the electrical code solder joints are not allowed unless a functional crimp is done first. Solder joints alone are not allowed.

redrok

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