Lotus Elan

Uninsulated spade crimp tool

PostPost by: RichardHawkins » Tue Mar 03, 2020 9:21 pm

Phillip,

I have bought four different crimping tools, none of which worked correctly. I had given up and was crimping loosely in order to hold the terminal in place so that it could be soldered. Speaking to a friend who had worked in the electrical/instrument industry all his life he advised me that although soldering was excellent for electrical properties, it could result in a brittle joint that could fail due to vibration.

An internet search revealed that there are very few good crimping tools and that they are all expensive. After much anguish I bought a Pressmaster tool (Swedish) from RS Components (Radio Spares). This thing has interchangeable jaws and is designed for maintenance work in the field, which I think fits our needs. I also found that there are standards used to test crimped connections and the only one I could find appropriate for us was a pull out test. My Pressmaster passed the pull out test. You can buy different jaws for different cable sizes and terminal types.

When you state 10mm I think you are referring to terminal spade size rather than cable size. My understanding of this is that it is rather like bolt sizes, the nominal size is bolt diameter not size across the flats of the hexagon.

Please remember that I am mechanical not an electrical person.

Hope this helps,

Richard Hawkins
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PostPost by: HCA » Mon Apr 06, 2020 4:10 pm

Are you competant with a soldering iron? Try folding the wire in the lower wings, then a dab of solder and then fold the top wings in with a small pliers - not forgetting to slide the plastic cover beforehand...

I gave up on crimping terminals ages ago due to the inadequacy of the 'affordable' crimpers' quality.
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PostPost by: JonB » Mon Apr 06, 2020 5:26 pm

Crimp, then solder, then heat shrink. That’s what I do.

You need a good mechanical hold on the wire when soldering, hence crimp first. If you are using those cheapo coloured connectors, pull the plastic off and discard prior to crimping, then solder, then cover spade (female) with heat shrink. Looks professional and may mitigate some of the risk of vibration cracks.

I suspect that, for most such joints, you’ll be long gone before the joint fails.
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PostPost by: JonB » Mon Apr 06, 2020 5:37 pm

Like this..

54A627E6-EFF5-43BF-8D45-6DD0ED574E19.jpeg
54A627E6-EFF5-43BF-8D45-6DD0ED574E19.jpeg (48.67 KiB) Viewed 1066 times


This connector isn’t completely sleeved but the heat shrink but you get the gist I hope.
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PostPost by: RichardHawkins » Mon Apr 06, 2020 7:34 pm

Apparently, soldering although producing an excellent electrical connection can become brittle and fail fail due vibration.

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PostPost by: Mazzini » Mon Apr 06, 2020 9:09 pm

RichardHawkins wrote:Phillip,

I have bought four different crimping tools, none of which worked correctly. I had given up and was crimping loosely in order to hold the terminal in place so that it could be soldered. Speaking to a friend who had worked in the electrical/instrument industry all his life he advised me that although soldering was excellent for electrical properties, it could result in a brittle joint that could fail due to vibration.

An internet search revealed that there are very few good crimping tools and that they are all expensive. After much anguish I bought a Pressmaster tool (Swedish) from RS Components (Radio Spares). This thing has interchangeable jaws and is designed for maintenance work in the field, which I think fits our needs. I also found that there are standards used to test crimped connections and the only one I could find appropriate for us was a pull out test. My Pressmaster passed the pull out test. You can buy different jaws for different cable sizes and terminal types.

When you state 10mm I think you are referring to terminal spade size rather than cable size. My understanding of this is that it is rather like bolt sizes, the nominal size is bolt diameter not size across the flats of the hexagon.

Please remember that I am mechanical not an electrical person.

Hope this helps,

Richard Hawkins


Richard,

Thanks for that. Which Pressmaster tool did you settle on?

Thanks,

Rob
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PostPost by: baileyman » Tue Apr 07, 2020 2:02 am

RichardHawkins wrote:Apparently, soldering although producing an excellent electrical connection can become brittle and fail fail due vibration.

Richard Hawkins


Perhaps it was here (I am foggy where), but somewhere recently it was said that the solder creeps up the wire strands by capillary action, creating a section of stiff rather than flexible wire near the connector. Then vibration shakes the stiff part rather than a flexible part. I had never noticed the stiffness before, but now I do!

John
Last edited by baileyman on Tue Apr 07, 2020 12:25 pm, edited 1 time in total.
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PostPost by: 69S4 » Tue Apr 07, 2020 7:06 am

How much of a problem are soldered connections in reality? Maybe the issue of vibration breakages might be of concern on spacecraft but in many decades of messing around with old cars and bikes I can't remember a single instance of a properly soldered connection breaking. Plenty of my attempts at crimped ones have given up the ghost though - mainly because of my ineptitude at crimping. The seeming difficulty of buying a good, reasonably priced crimping tool suggests plenty of others are producing sub standard crimps. In those instances, solder, for all its theoretical disadvantages, would seem to be the better bet.
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PostPost by: JonB » Tue Apr 07, 2020 7:35 am

My point exactly.
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PostPost by: nmauduit » Tue Apr 07, 2020 8:08 am

69S4 wrote:How much of a problem are soldered connections in reality? Maybe the issue of vibration breakages might be of concern on spacecraft but in many decades of messing around with old cars and bikes I can't remember a single instance of a properly soldered connection breaking. Plenty of my attempts at crimped ones have given up the ghost though - mainly because of my ineptitude at crimping. The seeming difficulty of buying a good, reasonably priced crimping tool suggests plenty of others are producing sub standard crimps. In those instances, solder, for all its theoretical disadvantages, would seem to be the better bet.


in my experience (automotive mostly, only a bit of satellite early in my career) it all depends on proper application of the procedure (hard to do without decent tool, esp. crimping) : in dubious cases (e.g. salvaging an older wire...) one may attempt to get the insurance of corrosion protection plus better contact resistance at the joint by adding a bit of solder to the crimped contact, BUT if the soldering takes too long, there is too much solder added, wire prep or soldering temperature or heat transfer is not adequate etc. chances are some solder will be sucked up by capillary action and the result will be worse than no solder regarding durability. A properly crimped wire protected with reducing contact grease is a safer shot for automotive (even motorcycle) applications in my opinion.
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PostPost by: Andy8421 » Tue Apr 07, 2020 9:26 am

A good crimp needs to create a gas tight seal between the cable conductors and the terminal, and provide mechanical support for the cable itself.

Production quality crimps need a combination of the correct tooling, the right terminal size and specification of terminal material and a cable with the right insulation diameter and correctly sized conductors. No wonder that a crimp tool bought from Screwfix, spade terminals bought from eBay and wire of unknown specification results in a poor connection.

Personally, I use decent quality un-insulated terminals, crimp, then solder. If the terminal needs insulating, either use heatshrink or a plastic boot. I have never had this fail. If you are trying to replace the terminal on an old loom, particularly one in the engine bay, then there is every chance water will have wicked along the cable and the conductors will be corroded. This is a challenge to fix - either try cleaning the conductors by scraping off the oxidiation, or cut the wire back to a point where the corrosion stops.

Good luck.
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PostPost by: RichardHawkins » Tue Apr 07, 2020 6:45 pm

Rob,

Sorry for not replying sooner, I missed your question.

I bought from RS Components

The Pressmaster tool I bought is described as

Mobile Crimp Tool 4300-3149/AAB. £46.32 plus VAT
Die Set, Fstyle,6.3/250 0.5-6.0mm sq. £52.68 plus VAT

TOTAL £118.8

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PostPost by: Mazzini » Tue Apr 07, 2020 8:53 pm

RichardHawkins wrote:Rob,

Sorry for not replying sooner, I missed your question.

I bought from RS Components

The Pressmaster tool I bought is described as

Mobile Crimp Tool 4300-3149/AAB. £46.32 plus VAT
Die Set, Fstyle,6.3/250 0.5-6.0mm sq. £52.68 plus VAT

TOTAL £118.8

Richard Hawkins


Thank you!
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PostPost by: Donels » Sun Apr 12, 2020 8:31 am

Ref crimping 10mm terminals. I have produced some professional looking and robust crimps for this size of terminal, without solder, by using 3 x 1/8 steel rollers and a vice. Tape the rollers to the vice jaws, 2 one side and 1 the other, and tighten. Easy and cheap.

Automotive Electrical Services sell excellent crimping tools for other sizes.
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