BAS I agree that you cannot mount the die in the stock the other way around.
However, you can run the die onto the thread the other way around. The thread would have to have been cut in the normal way first as - whilst a reversed die will cut - it is very difficult to make it start a cut, as it does not have a 'lead in' taper in that direction.
If you look at the cutting surfaces you should notice a small taper from front to back. This results in a tapered thread over the length on the die - so on a typical thread it is just the last die length of thread that has a taper. The conduit socket binds onto this taper. The trick is to tighten it just enough for a good mechanical and electrical joint, without over doing it, as if you do the socket will start to 'bell' on its leading edge and would eventually split.
A socket to conduit joint relies on this binding for a tight fit. Contrast this to the normal use of a nut and bolt - in which the bolt is stretched slightly to provide a secure fixing.
As I said above - the one time you might want to run the die in reverse would be on the long thread of a running coupler. Here you simply want to be able to run the socket onto the long thread and then tighten it onto the conduit you are extending. Running the die in reverse removes the taper and stops the socket binding on the long thread. A lock nut is then used to tighten the joint between the socket and the long thread.
Just as an exercise - try cutting a thread on some PVC conduit
. You have new sharp dies so you should be able to do it. You will probably need to hold a short length of conduit in a standard bench vice by crushing it. You should not need the handles in your stock as you don't need too much force. You will have to cut slowly and keep backing off and cleaning - good practice for steel
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