I bought some great pants from Ann Taylor recently, a rayon/cotton/spandex blend herringbone fully lined in poly, with cuffed hems. For $40, thank you additional 40% off clearance rack. When taking them apart to re-hem, I really liked the way they did it, so here for your future assistance (or total confusion, we'll see) is the method. This creates a 1 3/4" cuff, I'm sure you could modify the numbers to make it wider or narrower but I'll leave the math to you.
(If you're starting with already hemmed pants, you need to rip out all the previous stitching. Yes it's a pain, just get it over with and then pretend it didn't happen.)
1. You need a 3" hem allowance. That means 3 inches of fabric below where you want the pants to stop. Easiest way to figure this out is measure the inseam (inside leg seam from crotch to hem) on a pair of pants that is the length you want. If you don't have any to measure, fold up a hem and secure with pins, then try on. Repeat until you find the right length and then measure the inseam. Once you've marked the length, measure 3" past that and cut off the excess fabric.
|Pin is marking finished length, there is 3" of fabric past that. See those previous fold lines? I like my pants to be a little longer in back, so I altered the slope of the cut, which is why it isn't parallel to the old hem lines.|
|Tape attached to edge, with end folded over the raw edge and sewed down.|
|Pants are right side out, hem is flipped up. Fold up 4" and press.|
|PRESS. PRESS I SAY!|
|Sew 1/4" seam along pressed edge.|
|Pants inside out, fold seam towards bottom and leave 2 1/2" of fabric/tape.|
|Pants are right side out, fold tape hem to inside of pants.|
|Make a 1 3/4" cuff by folding the tape hem to the inside.|
|PRESS AGAIN. Are you tired of this yet?|
|Sew hem tape to inside of pants. There should be a nice fold of fabric to sew to that won't show on the cuff.|
|Cheater's best friend.|
|I worked in 3-4" sections, sticking down the tape and then ironing to fuse it.|
|And the outside!|
That's it! I'd say the second leg only took me about 15 minutes to do, so it's not a huge amount of time for a professional looking hem. Also, most of the other methods I've seen use a longer hem allowance (4"), so this one saves an inch of fabric. Good ready-to-wear is chock full of great methods to learn.