My guess is the next response you get will be "You shouldn't try this yourself, it is dangerous, leave it to the pros, just buy it."
I am all for learning about it and doing everything yourself...
Sorry bro, that's one of the few things I don't know how to do on my bike! I have never seen just ends for sale in order to make one. I imagine it's somewhat the same type of crimper as for coax (the hex inside of it).