The trouble with repro parts

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Post by Anonymous »

Blackbird wrote: Repo = crap
I understand what you mean mate, but that isn't necessarily true in all cases. I have just received stuff from PG Classics that I think are BETTER than the original. You would have to see both together to appreciate it, but it is obvious.


The biggest problem is with panels.
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Adam
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Post by Adam »

Dave wrote:
Adam wrote:Dave, I wonder whether your dealership inadvertently supplied the Grand Cherokee version?
God I hope so. That's what I have. :lol:
Doh! I thought you still had the green Cherokee. I must pay more attention :oops:
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Dave-R
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Post by Dave-R »

Its still the same green Adam. Just more "Grand". :lol:
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JohnR
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Post by JohnR »

I remember watching a program about someone who made body panels he said the problem was that the press they used was I think about 100 tons and the ones the car makers used was 300 tons so the panels were not exact copies also there were problems with the molds it was hard and expensive to get the molds perfect
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Post by Dave-R »

The "moulds" are steel tools. They are incredibly expensive to make.
They also wear out and become rounded and less sharp on the edges. So they need to be replaced now and again.

The people pressing repro parts are usually using worn tools sold on by the original manufacturer. Which is why they are not so sharply defined.
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MrNorm
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Post by MrNorm »

Dave wrote:The people pressing repro parts are usually using worn tools sold on by the original manufacturer. Which is why they are not so sharply defined.
Actually I think most of them (in the Mopar hobby) are long gone.
Most of the repos are made on new tools. It's true the dies are incredibly expensive, partly because it is a skilled job for the toolmakers who make these and partly because they are large lumps of metal!
However, in normal volume car production the dies need to last for hundreds of thousands of parts so they need to be built that way. When the manufacturers build the early prototypes they'll use what is referred to as 'soft' or prototype tooling. That is cheaper to make (though still very expensive), doesn't last as long, and very possibly doesn't give the same definition (that last bit is a guess). That's the tooling the repo guys will use as the volumes are so low and the cost is less. Nowadays I'd guess they CNC the main tools and the skilled toolmakers just Bananarama! off. That's possibly one reason why there has been a proliferation of parts - that and the fact that some companies have been pouring money in!
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Ivor
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Post by Ivor »

Interesting stuff.

There is an alternative method which involves lightweight modular press tooling which is made up from "patches" welded to a fabricated framework and profiled using a Keller machine.

This method produces a good panel, but the durability and possible movement of the tooling does mean that it is only good for short runs.

However, when properly set up, this method can I believe about the "soft" edges that Dave mentioned with worn tooling. You need an absolutely perfect original panel, jigged very accurately to cut the tool, but I've seen the results and they are a whole heap better than some repro parts I've seen , in fact I would say they were virtually OEM standard.
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