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MG MGA - Crimping

I would be grateful for some help as I just cant seem to make good connections with my crimper. Nine times out of ten after crimping, I find a small tug on the cable just to check all is OK will pull the cable free.
Do you think it's the crimping tool, the crimp, or just my technique? - attach a copy of the tool, etc in case it helps - thanks.

Graham M V

It may be the tool. Crimping insulated fittings is not ideal.

I use a crimper that sqashes the fitting into sort of a U-shape. If I do two squeezes per crimp, at right angles to each other (first flat, and then from the side) it works better. If you over-squeeze, you just ruin the fitting.

I found that taking off the plastic fitting altogether, and slipping a piece of heat shrink over the wire, then crimping the fitting tightly, then shrinking the insulation over the crimp worked much better.

As long as you are taking off the insulation, you can also just decide to solder the fitting, then cover with the heat shrink. I did this for the alternator connections and such where a loose fitting can ruin your whole day.

JIM in NH
AJ Mail

hi

do you use the crimper in the right direction?
the metal plate on the connector should be on the smal side of the crimper.

serge
serge

Are you using the right size terminal for the wire?

Speaking from a professional aspect, every major mfgr of crimps has recommended tools for each line of terminals they offer. Even within a mfgr, different terminal designs require different tools. Using a tool from one mfgr may not work on other crimps.

That being said, there is no reason you can't get acceptable crimps mixing suppliers. Perhaps you could put the terminal in the next smaller size die. But if you are having problems with the red terminals, as shown, then there is no smaller size.

Terminals accept a specific range of wire sizes. could it be that the larger wires work OK but those on the smaller end do not? One trick for this is to strip the wire 2x the required length and fold it back on itself, Then crimp. This increases the volume of wire inside the barrel.
Chuck Schaefer

Tend to agree with Chuck.

The tool looks like a quality item and ought to do a good job, we use that exact tool in industry.

I think your crimps are maybe too large for the wire size but that is only a guess and as Chuck says you could double the stripped wire to get a better grip.

The last refinery I worked at had abandoned the use of such crimps on wire sizes up to 2.5sq mm in favour of simply leaving the wire stripped and fixing it into a screwed terminal.

I think Jim is making reference to the basic type of crimping tool that does not work too well but with a little care can make a reasonable connection. Normally you should not apply the tool twice as this tends to compromise the joint.

Robert (Bob) Midget Turbo

I can second the above comments. The biggest reason for bad crimps is using incorrect size connectors for the wire being crimped. Bob is correct that your crimper looks like a good one. It looks like a ratchet crimper, but if not, you have to crimp until your dies come into complete contact or the crimp is no good.
On the U-shape crimps, you put the seam in the bottom of the U, and crimp the opposite side down. Crimping the seam could cause a poor crimp.
Mike Parker

Graham

I dislike those pre insulated terminals because you cannot check the quality of the crimp visually. Your tool does look a professional one though and terminal size, wire size and the crimp tool slot all make a difference.

Its rather trial and error I found even with the uninsulated crimps which roll over the terminal but I think many professionals use these in wiring harnesses.
John Francis

Thanks for all the response - yes the crimping tool is the ratchet type.
I had already tried to double up the wire without success but Serge's idea seems to help. The jaw of the tool has a wide and a narrow edge on each jaw. I was attempting to crimp with the wider edge, but for sure the thinner edge seems to work better.
I think my crimps are poor quality anyway so will get some better ones tomorrow.
Graham M V

Graham, better to use this sort of connector http://www.autosparks.co.uk/product_info.php?products_id=1973 (with a plastc sleeve), crimp up using ordinary wiring pliers then solder. It makes a much better job mechanically and electrically.
Lindsay Sampford

This thread was discussed on 19/06/2011

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