Forming a cone??

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Looking to possibly fab up a reverse cone megaphone exhaust for my motorcycle, and am having trouble envisioning how you would go about rolling the flat piece into shape.  I have worked out the math for the flat template and am wondering if you could use a normal sheet metal roller?  I've seen some crazy youtube videos of people using power rollers to do this, but I just have a manual.  Any thoughts, ideas?  Scott
Reply:If I remember correctly, you offset the rollers. In other words the gap between the rollers on one side is larger than that on the other. As you roll the one side tightens up faster than the other one. It's been at least 25 years since I did anything like this so I can't offer more than that..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Yes you can use regular slip rolls as long as the roll dia is ok for your small end. I have rolled thousands of cones at work on one and here is a little trick. Get some 1" angle 4 or 5 inches long and drill a small hole in the vee for a wire. Tack a small piece of sheetmetal on the end to hold your part. Tie a nut on a length of wire and put it thru the hole in the angle and drop it between the rolls with a small weight to keep it held into the rolls (see pic) Then start your part into the rolls and let it slide around the end of the angle iron shoe. It should form right up...Bob Attached ImagesBob WrightSalem, Ohio  Birthplace of the Silver & Deming Drillhttp://groups.yahoo.com/group/southbend10k/http://groups.yahoo.com/group/sawking/1999 Miller MM185 w/ Miller 185 Spoolmate spoolgun
Reply:Awesome!  That's exactly what I was searching for.Cheers.