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Over Crimp Issue

Practical Motorsport Wiring - Club Level

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Hi all,

Just wondering whether anyone has any advice on crimping non insulated butt splices?

This is the list of components I am using:

Rennsteig PEW12 with the hex crimp die (624 031 3 0).

8 AWG uninsulated butt splice purchased from RS components.


Tefzel 8AWG wire

I recently purchased the Rennsteig crimper and die and attempted to test crimp an 8 AWG Tefzel wire into the butt splice but it is resulting in an over crimp (see pic of the test crimp). I am unsure what has gone wrong here or whether I have incorrectly selected any of the the components. Any ideas?

Thanks all,


Attached Files

The copper crimps are your issue in this case.

You have purchased the 1.2mm wall copper lugs, which are typically used In hydraulic crimpers (you must have some decent grip strength to get these to crimp.

You been need the tin type (or thinner walled copper):


These are 4.5mm diameter for up to 10mm2 wire, as opposed to the 8mm thick units you currently have.

Attached Files

Hi Nathan,

Thanks for this. I wasn't even aware until now that I need to consider the diameter of the splice. I guess there is always something else for me to learn in doing my own wiring :)

Anyway I will purchase the correct diameter splice and them I'm good to go.

Thanks again. This info really helpful.


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