Shorten speedo type cable

I need to shorten this speedo type cable (actually a drive cable for the power seat in my '37). Its a spring type construction similar to a speedo cable and both ends have been shaped square. I was wondering about brazing it up solid on the cut end then filing it square, but there must be a better way? Thanks, Bill

 

I have made flex drives with that material before on some industrial equipment I built. I silver soldered it then finished it in the mill, or you could be careful and us a small hand grinder. The key is not to get it to hot or the temper will be gone and it will be junk. JC