Start by making a cuff, like this one. The idea is to have the wear on the hem stitching show. Then figure out how many inches you need to take off.
Now for the fun stuff! Divide the amount your taking off in 1/2 and place your tape measure or small ruler on the edge of the hem. Measure the same amount all around the hem, and pin in sections to make sure you will take off the same amount all around.
Place the sewing foot on the edge of the hem, like shown above, and slowly stitch the cuff all the way around. Make sure that it measures the same all the way around.
Okay, the hard work is all over. The original worn hem and stitching should be visible. If it's not, then it's either time to start over, or it's time to let the pros handle it.
Push the extra fabric inside upwards if it is a small amount. If it's a huge wad of fabric then grab your scissors and cut off some of the extra fabric, leaving about 3/4" to allow for fraying in the wash.
Turn the leg right side out and lay it flat. With your fingertips, press the seam you just created flat.
On the inside of the leg, use your iron to press the extra fabric upwards.
Then press the outside of the leg until it is nice and flat.
Admire your work!
There you have it! Can you tell the difference?
Update Aug 8, 2008. This forum thread linked to this page with some additional suggestions to ensure an even better hem. "just line everything up, and every couple of inches, make a stitch through the folded fabric, and then through your jeans (be sure to go vertically so it blends better). Go around a couple times in the same area (1mm apart x 3stitches is the best bet) and then tie them in double, triple, whatever knots, tie very well, and tight, and then snip off your excess. Maybe hit the fabric glue right on the knot to stabilize it." Visit that thread for the full conversation
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