narrow my rear

I know that some of you guys have probably narrowed your rear ends yourself...well the axle tubes at least.I have a 96 c1500 chevy rear end and i need to narrow it about an inch or so. I am wanting to narrow it myself but i want to make sure that it is true,do you build some kind of jig for the rear end??I will have the axles resplined but i want to try to do the tubes myself.thanks

You should build a jig for sure. There are a few different companys out there that sell jigs, but I can't think of any names. Sorry.