This is a really rewarding project. Once you have mastered inserting a zip fly the rest is a doddle!
(I don't mention it all the time, but, as a general rule: press everything as you go along!)
Step 1: Find a Good Pattern
This one is from the Great British Sewing Bee book 'Sew Your Own Wardrobe'. I've shortened it for shorts.
Measure yourself accurately & choose the correct pattern size.
Step 2: Pockets I
Zig zag the curved edge of your pocket facings.
Sew pocket facings (right side up) to pocket linings (right side up).
Step 3: Pockets II
Pin & sew pocket to trouser front (right sides together)
Understitch the lining.
Press to right side.
Top stitch the fold.
Step 4: Pockets III
Baste down the pocket sides & top.
Sew up the lining & zig zag the rough edge.
Step 5: Sew Up the Crotch Seam
Step 6: Zip Fly I
Sew the curved edge of your left fly shield.
Turn & press.
Pin & sew onto the Front of your Left-Front pattern piece.
Press & turn to the inside.
Step 7: (* Cutting Down Zip-Strip...)
Measure a bit more than you need.
Snip a bit of the teeth off from where you made the cut.
Open a bit of the end of the zipper, slide on one side & pull it down a little.
Jimmy the other side in & hold on to the tapes you created as you pull the zipper down.
Trim off the excess at both ends.
(Before the zipper is fully attached and sealed in, be VERY careful not to pull the zip head off the end of the zipper - as I have done, many times!)
Step 8: Zip Fly II
Turn & press the hem allowance of the right hand side of the fly opening.
Pin & tack the zip (facing out, closed with pull at top!) with the teeth just poking out.
Prepare the zip shield. Sew up 3 sides, turn & press.
Pin & tack over your original tacking (& remove 1st tacking - I use 2 colour threads to make it clearer).
Sew down and remove the tacking stitches.
Step 9: Zip Fly III
Pin the zip shield out of the way.
Turn your shorts right side up. Close the fly so there is no puckering. (Pic 1)
Pin the zip to the left side of the fly. Turn to wrong side and pin JUST the zip and left fly facing together. Tack this down before sewing. (Pic 2)
Sew up the bottom of the zip shield and the left fly facing. Through the bottom of the zip. (Pic 3&4)
Pin the zip shield out of the way and sew your left fly facing down with a top stitch curving to the base of the fly. (Pic 5&6)
Step 10: Sew Up the Side Seams
With right sides facing.
Space the pins evenly and remove as you go to avoid 'bolting'!
Step 11: Belt Loops & Waistband
Press the belt loops & top stitch down both sides. Cut into 6 equal lengths.
Pin belt loops onto right side of trouser waistline.
(1" from pocket. 2" from side seam. 1" from centre back edge. Both sides.)
Attach medium weight iron on interfacing to wrong sides of waist band.
Pin & sew 1 side of each waistband (right sides together) to the waist.
Turn the waistband right side up. Slacken the belt loops & pin on the back of the waistband, right sides facing.
Sew in line with the zip openings at the front, then along the length of each side of waistband.
Step 12: Centre Back Seam
Pin the centre back seam, matching the waistband up.
Sew together twice a few mm apart for extra strength.
Zig zag the raw edges and press open.
(I like to press to one side and top stitch down for even more strength to this seam)
Step 13: Finish the Waistband
Finish the waistband by invisible slip-stitching down on the inside.
Step 14: Sew Up the Inseam
Pin the inseam from crotch to hem on both sides.
Sew from the crotch down to one hem, then the other (crotch to hem again, crossing over at the crotch to strengthen).
Finish the raw edges with zig zag, then press open.
Turn up the hems at the bottom. Either:
Double hem & 2nd top stitch
Finally, give them a really good press with lots of steam and your shorts are ready!
Step 15: Hammer on a Snap Fastener
Follow the instructions in the kit!