A finished two-layer bridle leather shoulder strap with grain on both faces and hand stitching along both edges.
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Making a Strap From Two Thinned Layers

ByPeter Joeseph 'Briefcase Maker' Kalafatis

Grain on both faces sounds simple. The strap has five chances to fail before it is done.

A strap made from two thinned layers is a strap with no wrong side. Take two strips of bridle, split each one down, glue them flesh to flesh, stitch them, finish the edge, and both faces show grain. I split strap leather on an old hand-crank machine and stitch the two thinned pieces back together for exactly that reason. It is a lot of work for something most people will never turn over. The scenario below walks one shoulder strap through every step and says plainly where each step goes wrong, because each one can, and the strap only shows you which one after it is too late to fix.

Video: Splitting an English Bridle Leather Strap, from Marcellino NY Briefcase Maker on YouTube.

The job, and why two layers at all

One thick strip has a rough back. Two thin ones don’t.

Hands bonding two thinned leather strap layers flesh to flesh while pulling wax paper from between them.

The task: a shoulder strap for a briefcase, two grain faces, stitched down both edges, a ring or buckle at each end. I double-line my shoulder straps in bridle, and the back of the leather is why. A single strip of full-thickness bridle has grain on one side and flesh on the other. The flesh side is the side that rides on a coat, and it is the side that looks unfinished.

So you split two strips and put their flesh sides together. My earlier post on skiving and splitting bridle leather covers what thinning costs a strip. This one covers what happens after.

The question underneath is whether two layers are as strong as one. Leatherworkers have fought about it for years. In a 2016 leatherworker.net thread, Is leather stronger when laminated with an additional layer of leather, one member, Chief31794, said two layers come out stronger and stiffer. Dwight argued that two pieces bonded with Weldwood contact cement would not come apart and that bonding flesh to flesh protects the grain. Others, including a saddlery and a member citing old trade manuals, said a single heavy strap outlasts two, because the strength lives in the fibers and stitch holes let moisture in.

Nobody in that thread brought test numbers. Neither have I. Hold that thought until the last section.

Step one: splitting the two strips

The splitter sets the thickness. It also sets the first mistake.

Weaver Leather Supply’s Master Tool splitter, a hand-crank machine of the same family as mine, is sold for “precise, even splitting,” with a hollow-ground blade and a lever that sets the thickness for leather from 3 to 14 ounces. My own is older. You can watch me run a leather strip through it in Splitting / Skiving Leather Strip With An Old School Hand Crank Weaver Machine.

What goes wrong: the split comes out uneven. The same Weaver page carries a two-star review from a buyer who said the machine would not split 8-ounce leather consistently. A blade out of true, a strip fed crooked, a lever that creeps: any of those leaves a thin spot, and a thin spot in one layer of a strap is the spot that stretches first under a loaded case.

The second failure is a mismatch between the strips. In a 2013 thread on how to make a double layered belt, Dwight said he tries to cut both pieces from the same hide. My opinion is that this matters more than people think. Two strips from two hides can stretch at two rates, and a strap built from them pulls against itself.

My advice: split both layers in the same session on the same setting, check each one along its whole length with your fingers before glue goes near it, and cut both strips longer and wider than the finished strap. The extra is what you trim away when the layers don’t land exactly, which they won’t.

Step two: gluing flesh to flesh

The glue grabs once and keeps what it grabs.

Macro of a two-layer leather strap edge showing the seam between layers and saddle stitching beside it.

Contact cement goes on both surfaces and has to dry before the two meet. Weaver’s page for toluene-free Barge cement gives a dry time of 10 to 15 minutes, describes dry time as how long the two surfaces have to stay apart, and notes that humidity can change it. Then the pieces go together.

What goes wrong first: the strips touch in the wrong place, and contact cement doesn’t forgive. A 2015 thread on how to make a double-sided strap has a fix for it. Tree Reaper said to cement both halves, let them dry, lay wax paper between them, line them up, and pull the paper out slowly so the bond closes a little at a time. He also suggested taping the bottom strap to a solid surface so only the top one moves. The original poster, Redhairing, tried the wax paper and called it “much more flexible and forgiving.”

Then the edges. Mike DeLoach, in the 2013 belt thread, put it in four words: “Glue all the way to the edge.” An edge that isn’t bonded opens later, under the stitching, and takes dirt and water into the seam.

The third failure is impatience. In a 2021 thread on gluing a two piece belt, a member named Lobo pressed his layers under a steel billet and cured them overnight, and warned that “Rushing through any part of the process is a sure method for failure.” That sentence should hang over every bench.

Step three: flat or over a curve

A strap bends one way all its life. Glue it flat and one layer has to give.

Here the strap meets geometry. Two layers bonded flat are the same length. Bend them and the outer layer has farther to go than the inner one, so one stretches and one bunches. In a 2015 thread, When laminating leather belts, bond flat or curved, JLSleather described the give in exactly those terms. Several members said they bond flat anyway. Dwight said the inner layer sometimes puckers but that, after months of wear, “the wrinkles go away.”

Others curve the work while the glue sets. In the 2021 thread, chiefjason glued belts over a large pot, and JohnnyLongpants suggested coiling a glued belt around a five-gallon bucket and leaving it overnight, with the outer blank cut a little longer than the inner.

A briefcase shoulder strap isn’t a belt, though. A belt lives in a circle. A shoulder strap hangs mostly straight and folds over a shoulder only in the middle. I set my shoulder-strap rings on the top edge of the case, not on the gusset, so the strap drops straight and doesn’t wrinkle the suit under it. In my view, that makes flat bonding the better bet for a strap like this one, and a pucker on the inside, if one shows, is a smaller fault than an outer face glued under tension.

What goes wrong: the wrinkle lands on the wrong face. Bond flat, carry it hard, and you may find out which face was the inner one.

Step four: trimming, edges and stitching

The edge tells everyone the strap is two pieces, unless you make it lie.

A hand-crank leather splitter thinning a strip of bridle leather for a two-layer strap.

Trim first. DeLoach cut his liner slightly oversized and trimmed it to the front after gluing, and he said to get the edges straight before marking a stitch line. JohnnyLongpants, in the 2021 thread, laid the belt face down and cut the liner flush with a groover, then beveled the leftover glue away. Same idea. Trim after the bond, not before.

What goes wrong at the edge: a glue line. Two layers pressed together leave a seam right in the middle of the edge, and if glue squeezed out it shows as a dark streak. DeLoach warned against beveling the flesh side where the two halves meet. Bevel the grain corners, as in beveling and creasing a leather strap, and leave the middle alone.

Then the finish. I hand-burnish edges when the work allows it, for tradition. On lined work I use a latex-based edge paint, because the paint also glues the layers together at the edge. A two-layer strap is lined work wearing a different coat. In my opinion, a burnish on a doubled bridle edge can be done, but the paint is the safer answer where the seam won’t close under the slicker. The site’s post on the burnished edge makes the case for the other side of that choice.

Stitch last. DeLoach also warned not to sew while the leather is wet, especially close to the edge, because the leather bulges around the needle. Dry it, groove it, punch it, and run a saddle stitch down both edges. Every hole goes through both layers and the bond between them.

Where one thick strap beats two thin ones

Every step above is a place to fail that a single strip never has.

Now the part I owe you. I have just spent five sections building a strap that fails at the splitter, at the glue, at the curve, at the edge and at the needle. A single strip of full bridle fails at none of those, because none of them happen to it.

The single-layer camp in that 2016 thread has a real point. Big Sioux Saddlery said one heavy layer outlasts two sewn layers on heavy tack, because stitch holes let moisture in and layers can come apart. JLSleather agreed on the holes: “put no holes where they don’t needa be.” Every row of stitching on a doubled strap is a row of holes a single strap doesn’t need.

I stitch my buckles on by hand, no rivets, which is a bet on holes. Holes, done right, hold. Holes, done wrong, are the whole problem. The two-layer strap asks you to trust your glue and your stitching at once, and a single layer asks you to trust neither.

And yet I still split them. Grain on both faces looks finished against a coat, and the flesh side of a thick strip, however well slicked, looks like the back of something.

My opinion, plainly: for a strap that carries a heavy case every day, a single thick strip with a well-finished back is the stronger bet. For a strap where both faces show, two thinned layers are worth the extra ways to fail, if each step gets done slow. Which of those my next strap is, the customer decides.

Barge All Purpose Cement, Quart: A quart of solvent-based contact cement. See it on Amazon (affiliate link).

Jmuiiu 7-in-1 Adjustable Leather Groover: An adjustable stitching groover for cutting a channel along the stitch line. See it on Amazon (affiliate link).

Mandala Crafts 150D 0.8mm Black Flat Waxed Thread: A flat waxed polyester thread, 0.8 mm, in black, for hand sewing leather. See it on Amazon (affiliate link).

John James Saddlers Harness Blunt Point Needles: A set of blunt-point harness needles, five sizes with five needles of each. See it on Amazon (affiliate link).

Craft County Brass D-Ring, 1 Inch: A solid brass D-ring, one inch inside. See it on Amazon (affiliate link).

3Pcs Wooden Sandpaper Block Set: A three-piece wooden sanding block set with bevel and wedge shapes. See it on Amazon (affiliate link).

As an Amazon Associate I earn from qualifying purchases. A commission may be earned if you buy through this link, at no extra cost to you.

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