Why your strap isn't the width you think it is
Custom watch bands and the myth of exact widths
Let's just get this right out in the open: When it comes to width, a properly made custom watch band is not the exact width you ordered. If your strap maker has any knowledge and skill they're going to do you a huge favor and NOT make your strap exactly the 22/24/26 etc. width you ordered. Instead, as I hand craft your watch band I take several details into consideration to be sure that you end up with a long lasting handmade watch strap that won't shrivel up on you or end up with the edge coat all rubbed off. How? Follow along.
Looks perfectly straight right?
Your lugs and why your strap hates them
The lugs of your watch are going to be a set width, being made of metal and all. Most watches range in lug width from 18mm up to 26mm, usually in even numbers. For the sake of this article lets just assume you're getting a 24mm wide strap, a common width for Panerai straps. So you want your hand crafted leather watch band to be exactly 24mm at the lugs, right? Wrong! Yes the exact distance between the lugs of your watch may be 24mm, but unlike the rigid metal your watch lugs are made of, the leather that your custom watch strap is made of will flex and change with use, particularly as you put your watch on and off each day. Tugging on that strap pulls it along the length, which can have the effect of narrowing it slightly along the width. This is exacerbated when the strap is wet. The net effect is that over time the lug area of your strap may shrink a small amount, and if it started out at exactly the "right" width... now it's exactly the wrong width and you'll see that shiny lug screw or springbar peeking out. Yuck. To combat this, a skilled strap maker will craft your custom watch band to be just a bit (around 1/2mm) "too wide" at the lugs. This will make your strap a little bit of work to mount, but in trade for that work you'll find that over the years your strap should maintain a nice, snug fitment between the lugs of your watch instead of shrinking up.
Looks like Bond should have used a pro
24mm means 24mm
And that means at the lugs and buckle. So now that we know the lugs of your handmade leather watch band need to be a little bit wide, what about the buckle? If the buckle you're using is 24mm wide that means that like the lugs, the buckle is exactly 24mm interior width. But now you definitely don't want your high end strap to be exactly 24mm wide or, even worse, just a little wider. Where the strap tongue passes through the buckle the strap needs to be just a bit narrower than the 24mm width of the buckle so that the edges of the strap don't rub on the inside of the buckle every time you put it on/take it off, which will either fray the leather or rub off the edge coat after a while. Some contact is inevitable, but a properly made custom watch band will have a slightly narrower tongue so that it can travel through the buckle cleanly. Conversely, like the lugs, with the buckle side of the strap you want it to be just a bit wide again so that the strap mounts firmly to the buckle and doesn't shrink.
Small gaps make a big difference