I have a skills test for a job interview this weekend and have been brushing up on some of my rustier skills.
When it came time to do the fly front zipper, I realized that I had almost completely forgotten how and I certainly couldn't find any tutorials. I ended up taking apart one I had done years ago and going from there. I took photos of the process so I would not forget, and figured I would make a tutorial while I was at it so that others could benefit from my learning experience.
Cut 4 fly pieces. It should be 3"-4" wide and as long as your zipper. Remember to include seam allowances
Sew the fly pieces together so that you end up with 2 "fly pockets" Remember to clip your curves. Press (frequent ironing throughout the process helps to keep things nice and neat).
Right sides together, attach one of the fly pockets to the left side of your garment opening. (You may sew the garment together before hand, leaving just enough to install the zipper. I personally have a much easier time if I leave the two sides in pieces as long as possible).
Lay your zipper upside down on the attached fly pocket and baste/sew stitch down, being sure to leave at least about 1/4" between the teeth and the seam of the garment.
Fold the fly pocket over (remember you are pressing seams as you go) and stitch the top edge down to your garment.
If you have not done so already, stitch the two sides of your garment together, stopping at the first fly pocket. Press the remaining seam allowance under and pin the other side of the zipper to this. Stitch the zipper to the seam allowance (do NOT sew through to the other side of the garment)http://img.photobucket.com/albums/v382/henabebe/january2007111.jpg
zipper sewn to seam allowancehttp://img.photobucket.com/albums/v382/henabebe/january2007113.jpg
your garment should now look like this with the zipper closed
Still sewing only to the seam allowances and not the outside of the garment, attach the second fly pocket to the zipper tape, allowing room for the zipper pull to move. You may finish the top of this pocket in some way, but do NOT attach it to the top of the garment like you did pocket 1.
Go back to fly pocket 1 and pin it flat to the garment. Stitch it down to the garment about 1/4" from the edge of the pocket taking care to make your lines straight and even.
Replace your machine thread with top-stitching or button holing thread and adjust your machine's tension accordingly (use a piece of scrap fabric). Some people like to put stop-stitching thread in the bobbin as well, but a lot of home machines really don't handle this well and you're usually fine with regular thread on the bottom. Sew over the line you made from the opposite side (assuming it is straight) and make another row of stitched 1/4" inwards. Be careful when you go over the zipper - use the hand crank if you need to (also a good idea if you have trouble with the curve).
Attach a waistband and you're done!
I wish I could show you the finished garment that goes along with this tutorial, but it ended up being..kind of fugly. I put it away until I can figure out what needs to be done to fix it. Anyway, I hope this was helpful to some people!