To hem military trousers using a military hem finish, you will need to properly measure the trousers before you get to work. You will be cutting off the excess fabric, so make sure you double check your measurements. When you hem a pair of trousers, it is important that you make the new hem resemble the original hem as closely as possible.
Pin the hem to the appropriate length.
Even the hem by ensuring the pins are straight from the centre to the front and from the centre to the back. For most slacks, the front is slightly shorter than the back.
Press the measured hem using a pressing cloth. Silk organza makes a good pressing cloth but other commercial and homemade versions also work well.
Turn the trousers inside out and mark the amount of excess material that needs to be cut off. Because military hems break over the "instep" and slant from front to back, the fabric will not turn up evenly all the way around. If the angle is less than 13 mm (½ inch) you can just let out the side seams to make the hem even. For larger angles, make a slit in the centre front hem to get the fabric to go straight.
Slip a piece of old fabric or a paper towel under the slit and spray it with an anti-fray solution to prevent it from fraying.
Start sewing the hem. Start at the slit and sew all away around until you reach the other side of the slit. If your hem was less than 13 mm (½ inch) and you didn't make a slit you can start sewing at the side seams and work your way around. The new hem should resemble the original.