Originally Posted by Youngblood
But back to the curved surfaces and rolled hems for a minute. The basic problem is the geometry, it just doesn't want to fit when you do a rolled hem. The bigger the hem and the deeper the curve, the more it doesn't want to fit. You can force it to happen but it likely will not look as neat as the rolled hems you see on straight edges.
That's why _I_ don't like to use grosgrain on tarps edges, particularly cat cuts. The geometry of grosgrain and I don't get along at all well. It loves straight lines. Seam binding or bias tape is made to take those curves with greater grace. I roll my hems simply because I use what I have on hand which often does not match the base fabric. So I roll twill tape into the hem to provide the strength and stabilize the curve. For _me_ that works better. If I had the machine that would stitch the seam and apply the binding all with only one pass through the machine I would use it and love it. But.... I would have a hard time trying to justify such an investment to my wife for the sheer purpose of "making gear."