- Check your manual for the best settings for your machine. My comments are based on a Janome 644D, but the same logic will work across a lot of other machines as well.
- Disengage your knife for a great 'rolled' finish (if you don't, it tends to just cut the fabric off rather than 'rolling' it over and you can get the little fabric worms sticking through the stitches)
- Take out your left needle
- Shorten your stitch length. Janome's have an 'R' setting for a rolled hem, but I like to make the stitch length even shorter to get a nice tight, full stitch
- Match thread to the dominant colour of the fabric you are using. A fast and easy option is to just replace the upper looper thread with a spool of your sewing machine thread.
- To change the thread over, trim the existing thread close to the spool, tie on the new thread, wind the handwheel forward to release the threads and then pull the upper looper thread until the new colour comes through the upper looper. If using your sewing machine thread, you will need to remove the spool holder.
- If you have woolly nylon that matches, try using that in your upper looper (you will likely have to reduce your tension down if using the nylon too), it will give a lovely thick, tight finish, but be warned, it is not loved by the iron.
This is how your rolled hem will look.
If you are not loving your right needle thread being the existing colour, then swap that thread over as well. If you are using a pale pastel colour for the rolled hem, then you can usually just leave your needle thread as white and it will still look great. When changing the needle thread, I find it just as easy to replace that thread entirely rather than trying to tie on the new one because you can't pull the knot through the needle anyway.
Hope some of these tips help you get a great rolled hem finish.