Skiving and thinning the ends of a strap

You fold the lug end round the spring bar and it won't close. Or it closes, but there's a hard lump that stops the strap sitting flat against the case. The leather is too thick at the fold. Skiving is the usual fix.

What skiving is

Skiving means thinning down a leather edge¹. Wikipedia's description is a little wider. It reduces the thickness of leather, especially in areas that are to be bent or folded and which must be pliable without becoming weakened². It also keeps an overlapping area from becoming unnecessarily bulky².

Two ideas in there matter for straps. You thin only where the leather bends or overlaps. And you stop before the leather is weak.

Where a watch strap needs it

Three places, and each one is a fold or an overlap.

• The lug end. In one maker's tutorial, the strap is folded to create a loop for the spring bar¹. That fold is two layers of leather in a small space.
• The buckle end. The same maker skives the liner's top layer to make a smooth transition for folding the outer, forming a loop for the buckle spring bar¹.
• Joins. If you build a strap from a liner and an outer piece, skiving the joining edges gives a smooth change from one to the other¹. Wikipedia also notes the technique is useful for joining long strips of leather together to form belts or watchbands².

Why thick leather causes the problem

Tandy warns that heavy leather can be awkward in two ways: sewing and folding³. A fold puts two layers of leather in one spot, and a lining adds more. The same source says to count the layers together, not one at a time³.

So before you reach for a knife, decide whether you've picked leather that's already thin enough. The leather page covers the thickness ranges. Skiving is for the fold, not a way to rescue leather that was far too heavy to begin with.

How to do it

The sources agree on a few basics. They don't give a depth in millimetres that works for every strap, so I won't invent one. Use your own watch as the test.

• Use a very sharp knife. Namoki says skiving is done using a very sharp knife¹.
• Work on the back. Skiving is usually done on the flesh side of the leather rather than the finished side².
• Mark how far the thinned part should run. Keep it to the fold and the stitched area, and leave the body of the strap at full thickness.
• Take off a little at a time. You can always remove more, but you can't put leather back.
• Fold the end round a spare spring bar or the real one, and see if it lies flat.

A round knife is another option. Tandy calls it optional and ties it to skiving edges for more advanced makers⁴. A utility knife with a fresh blade is the plainer starting point, and the maker's tutorial lists a skiving knife among its cutting tools¹.

Keep it safe

Skiving knives are very sharp, so work on a cutting mat and keep your other hand behind the blade. Keep blades away from children, and cover them when you stop.

Check before you stitch

Fold the thinned end into its final shape and press it against the watch case. If it springs open, thin it a bit more. If it feels floppy, you've gone too far, and you'll need to cut a fresh piece. Test on an offcut of the same leather first, so your good piece isn't the practice run.

When the ends fold flat, you can stitch the strap.