Attachment & Sizing

By David Christianson, Certified Master Watchmaker

Fitting or replacing a watch strap or bracelet is easy. If you feel uncomfortable doing it on your own, you can also ask a jeweler or watchmaker to service your watch for a small fee.

Width & Case Attachment

Leather watch straps are sold in a variety of end widths designated in inches or millimeters. Leather is flexible enough to interchange inches for millimeters. For example, you can use an 18 mm width instead of 3/4 inch. The difference is only 1 mm. If the strap is 1 mm wider than the lug space, it will still fit fine. Any wider, however, and the strap will bulge in a short time.

Notched Ends

The end width of the new strap must fill the entire space between the lugs of the watch case. If it's too short, the spring bar will bend, crack or pop out.

Some watch cases require leather straps with notched ends or notched corners rather than the more common spring bar between the lugs (see diagrams on the left).

To replace these, lay a standard leather strap against the end of the watch case and mark the edges of the notch with a sharp knife incision. Use notching pliers to cut out the width and depth of the notch. Hide the fresh edges with a matching color felt marker and replace the spring bar as required. Get replacements from your watch strap retailer.


Straps are designated as short, regular, long and extra long. When a new strap is being fitted, note your old strap size and ask yourself how comfortable it was. Did you have to use the last hole? Did you use the first hole and the watch was still loose? Either case may require a new length.

Don't fit a small wrist with a long or extra long strap unless you want the end of the strap to hang out. Ideally, the fit should allow three or four holes at the strap's end. If you prefer the current strap, punch a hole in one end or the other for a better fit.

Punch The Hole

To make the strap fit more snugly, punch a new hole toward the case. To make it looser, punch the hole toward the free end. Here's how to proceed:

  • Use a staking tool and a concave punch with an end that fits the diameter of an existing strap hole. With the punch in the staking tool, rotate the table to locate a hole in the table that allows the punch to slip 1 mm deep. Line up the punch and the hole and lock down the table.
  • Measure the space between two existing holes and measure that same distance from the last hole to locate the new one. Place the strap in your staking tool and be sure the new hole is centered between the strap edges.
  • Strike the punch firmly with your staking hammer. The plug from the new hole will lodge in the staking table hole or cling to the back of the new hole. It's easily removed with tweezers or a sharp knife.
  • Attach the strap to the case and to try it on.

Reprinted with permission from the Professional Jeweler Magazine. For more information, please visit the American Watchmakers-Clockmakers Institute (AWCI).