Q: Which zipper should chinos use?
Chinos work with a size 4.5 metal zipper or a size 5 vislon, closed-end, and a locking slider. The twill is lighter than denim, so a size 4.5 brass gives the fly enough strength without a bulky chain; a size 5 vislon is the practical alternative when the trouser is garment-dyed or washed, because molded teeth keep their colour and do not corrode. Keep the tape narrow so the fly seam stays flat under a pressed crease.
- Size 4.5 metal or size 5 vislon, closed-end.
- Locking slider with a short, flat pull.
- Narrow tape and a clean seam allowance at the waistband.
The usual error is fitting a size 5 brass because it is the standard denim part: on a 240 gsm twill it looks heavy, the chain ridge shows through the pressed fly, and the top of the zip bulges under the waistband. The second pitfall is a tape that is too wide, which forces the seam allowance out and produces a visible line down the front of the trouser.