All metal watch straps comprised of links are adjustable. Shortening a watch band is as simple as removing a link--just remember to keep it in a safe place. If you want to lengthen your metal watch strap, you must get another link. Many watches come with extra links. If you don't have one, contact the manufacturer or see if a jeweller can make one.
Spread a towel over your work area.
Inspect the watch band. Somewhere on the links there will be a hole, a slight depression or protrusion. This marks the spot where the pin connects removable links. The spot may also be accompanied by an arrow pointing in the direction in which you are to remove the pin.
Remove the link pin. The method you use will vary slightly from watch to watch. If the pin goes straight through the watch, use the appropriate sized link-punch tool to push the link pin through. Stubborn link pins should be started with the link-punch, then pulled out with needle-nose pliers. For other link pin configurations, use the appropriate size link-punch to remove the link pin in the direction of the arrow.
Try the watch on. Drape it over your wrist to see if it will fit once the link is removed. If it's still too big, you may need to remove another link.
Remove the link(s). If removing one link, simply extract the link pin from the other side of the unattached link (following the method you used in Step 3). If you need to remove a second link, take it from the other side of the watch clasp.
Attach the links. Reinsert the link pin(s) by reversing the method you used to extract them. Stubborn pins may need to be hammered in with the small hammer that's part of your watch repair kit.
Remove the link pin with your link-punch tool and needle-nose pliers, if needed. For other link pin configurations, use the appropriate size link-punch to remove the link pin in the direction of the arrow.
Determine how many links you need to add. Try the watch on with the extra link(s) held in place. If you need to add two links to your watch, the second must be added on the opposite side of the clasp.
Attach the link(s) by reinserting the pins, reversing the method you used to remove them. Use the link pin you removed to attach one side. The second pin may already be inserted in the other side of the extra link. In this case, remove it. Stubborn pins may need to be hammered in with the small hammer.
If you are unsure how to remove your watch's pins, take it to a jeweller to be adjusted.