A vegetable-tanned leather bend with a strap strip and a test offcut cut from the same hide for practicing on scrap leather.
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Practicing on Scrap Before the Good Hide

ByPeter Joeseph 'Briefcase Maker' Kalafatis

Every mistake has to land somewhere. Pick where.

Practicing on scrap leather is how you keep your mistakes off the piece of hide that cost real money, and the easiest way to see why is to follow one small job down the bench and watch where it goes wrong. The job is a strap end: a single strip cut from a good vegetable-tanned bend, beveled, punched, stitched to a keeper, dyed and oiled. Nothing fancy. Every step is a place where an untested tool or an untested bottle can ruin the strip, and the only time I cry at the bench is over a ruined briefcase, so I take the small ruins seriously too.

Video: Conker bridle leather edge bevel, from Marcellino NY Briefcase Maker on YouTube.

The job, and the strip you cannot replace

One good bend, one strap end, no spare.

A hand testing an edge beveler on a leather offcut beside a test piece with an over-beveled edge.

Set the scene before anything goes wrong. You have a bend on the table, the firm piece of the hide that Weaver Leather Supply’s leather terminology page describes as a back with the shoulders trimmed off. You paid for it by the square foot. You have cut one long strip from the cleanest part of it, and the rest of the bend is spoken for.

That strip is now the most expensive thing on the bench. Not because of the leather alone. Because of the order of operations, which only runs one way.

Leather does not forgive the way wood does. You cannot plane a bevel back on, fill a stitching hole so it disappears, or bleach a dye out of vegetable-tanned leather and get the original colour back. Each step removes something or adds something permanent, and the next step builds on top of it. A mistake at the bevel is still there at the dye. A mistake at the punch is still there when the strap is on somebody’s shoulder.

So the plan I’d give anyone is simple to say. Every tool and every liquid that touches the good strip gets tried first on something that does not matter. What follows is what happens, step by step, when it is not.

The trouble is that the steps are where all the hope lives. People skip the test because they want to see the real piece come together. That impulse is the whole reason this post exists.

The bevel that takes too much

Wrong size, wrong weight, and the edge is gone for good.

First step: knock the square corners off the edge with a beveler. The mistake here comes from the tool drawer, not the hand.

Bevelers come in sizes, and the sizes are matched to leather thickness. Weaver’s listing for its Master Tool edge beveler gives a table: size 0 for 4 to 6 oz leather and very fine edges, size 1 for 4 to 10 oz, size 2 for 8 to 12 oz, and size 3 for 12 oz and heavier. The page sums it up in one line, “Lower numbered bevelers are for lightweight leathers.” One buyer’s review on the same page says the beveler they bought was ineffective on thinner leather because they had skipped the smallest size. Pet Hardware’s listing for a Craftool edge beveler gives the same kind of match from the maker, rating its 1.2 mm blade for 2 to 3 mm leather.

Now run the strap end without a test. A beveler one size too big on a strap that is a little thinner than you guessed takes a fat chamfer off both corners, and the edge comes out with a pointed ridge down the middle instead of a round one. You cannot add it back. Sanding makes it rounder, not thicker.

Run the same beveler down six inches of offcut from the same bend first. The chamfer tells you in ten seconds whether the size is right, and whether the blade is sharp enough to cut instead of tear.

Holes that wander off the line

On thick leather, the punch decides the stitch before the needle ever does.

A test seam on scrap leather cut open to show a pierced thread inside a stitching hole.

Second step: punch the stitching holes. Weaver’s hand-sewing walkthrough has you cut a guide line with a groover, then strike stitching chisels with a rawhide mallet on a poly board. It also notes that a piece of scrap placed under the project helps the chisels go through the leather more easily. That is the first job for scrap on this strap, and it never touches the finished piece.

The mistakes here are small and permanent. A chisel held off true comes out of the back somewhere other than where it went in, and every hole after it inherits the lean. A hole is a hole. It does not close back up because you wish it would.

On thick leather I pre-punch every hole and line them all up before a needle goes anywhere near the work, because thick work will not stitch otherwise. On a scrap of the same thickness you find out how hard to hit, whether the chisel is clean through both sides, and whether the back looks like the front.

That last check is the one I care about most. A row of holes that looks straight from the grain side and wanders on the flesh side gives you a crooked seam on the back, and on a strap the back is half the strap.

A seam that looks fine and is not

The thread you speared is still in there, holding nothing.

Third step: stitch the keeper to the strap. Two needles, one thread, both needles through every hole.

My hand-stitching page says what goes wrong here and why nobody sees it. With each hand stitch, the needles enter a hole that already holds thread, and it takes skill not to puncture that thread, which a machine never has to worry about. The same page warns that a stitch can look good outside while the hidden layers hold future problems.

So you stitch the strap end. The face looks even. The back looks even. And somewhere in the middle of the run, a needle went through a strand instead of beside it, and that stitch is now holding with half its thread. Nobody will know until the keeper starts to lift, months later, on someone else’s strap.

On thick leather the needle fights you. I wax the needles and pull them through with pliers when the leather is heavy enough, and the moment you reach for pliers is exactly when you stop feeling what the thread is doing.

Sew a short seam on two offcuts first. Then cut it apart with a knife and look inside the holes. A speared strand shows up as a split, fuzzy thread where a clean one should be. Find that on scrap and you learn your angle. Find it on the strap and you learn it from the customer.

The rule on The Maker page goes for every seam: “The side nobody sees is where a weak stitch gets found out.”

Dye and oil that come up the wrong colour

The bottle shows you one brown. The leather decides another.

Dyed and half-oiled leather test strips beside a white rag showing light colour transfer.

Fourth step: colour and oil. Here the scrap test is printed right on the instructions. Fiebing’s own leather dye page tells you to “practice on a scrap piece of leather before using on valued articles.” The page adds that every leather takes dye differently depending on the type and the tannage, and that a finished surface has to be stripped close to natural leather before dye can penetrate. A UK retailer’s listing for the same dye gives the same warning in its own words, that “every leather type absorbs dye differently.”

Skip it on the strap end and the colour can come out lighter, darker, or streaked. Fiebing sells a deglazer for stripping old dye and finish, which tells you something: getting colour out is a separate job with its own bottle, and I would not want to try it on the one strip I cannot replace.

Oil does its own thing. On undyed vegetable-tanned leather, sun and oil both speed up the patina, so a coat of oil on natural leather darkens it, sometimes more than you wanted. My Leather Care page adds that light colour transfer can happen at first, and the leather wants conditioning often until the dyes settle. Better to find that out from a scrap rubbed against a white rag than from a customer’s shirt collar.

Dye a test strip, oil half of it, let it dry overnight, and look at it in daylight. Then decide. I would rather lose a strip of test leather than the strap.

Scrap is a liar if you pick the wrong scrap

The only offcut that tells the truth comes from the same hide.

Here is where the whole argument turns on itself.

Everything above says practice on scrap. But most scrap lies. A bag of mixed offcuts from a supplier, a piece of belly from another hide, a strip of chrome-tanned leather left over from someone else’s project: none of them behaves like your bend. Fiebing’s point cuts both ways. If every leather takes dye differently, then a test on the wrong leather tells you about the wrong leather.

The belly is the worst offender. I cut briefcases from the bend and nothing else, and the belly goes in the trash. Weaver’s glossary marks the belly as coming from the underside of the animal, and Weaver’s article on cuts of leather calls it a fine starting cut for a beginner but the least preferred piece in a production shop. That is the split in one sentence. Cheap enough to practice on, too unlike the bend to tell you anything honest about it. A bevel that looks right on a belly scrap can still be the wrong size for the strap, because the strap is not the same thickness or the same firmness.

So the honest version of the advice costs you something. The best scrap is a strip of the good hide itself. Cut your test piece from the same bend, the same weight, ideally right beside the strap you are about to make. That means giving up a few inches of leather you paid good money for, on purpose, before you have made anything. Every beginner hates that part. I understand why.

The hide does not grade on effort. A strap end made without a test can come out fine, and sometimes it will. The day it does not, the cost lands on the one strip you cannot replace. The Basic Techniques section takes each of these steps on its own, and the Care and Cleaning section picks up where the oil leaves off.

Weaver Leather Supply Diamond Leather Stitching Chisel Set: A set of 4 mm diamond stitching chisels for punching saddle-stitch holes. See it on Amazon (affiliate link).

Leather Carving Hammer Mallet: A nylon-headed mallet with a wooden handle for striking chisels. See it on Amazon (affiliate link).

Fiskars 18 x 24 Inch Self-Healing Cutting Mat: A self-healing cutting mat, 18 by 24 inches. 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).

Fiebing’s Pro Dye, Black, 4 fl oz: An alcohol-based leather dye in black. See it on Amazon (affiliate link).

Fiebing’s Leather Deglazer, 4 fl oz: A 4 fl oz deglazer used to prepare finished leather for dye. See it on Amazon (affiliate link).

30-Pack Wool Dauber Brushes with Metal Handles: A 30-pack of wool dauber brushes with metal handles for applying leather dye. See it on Amazon (affiliate link).

Skidmore’s Leather Cream: A leather conditioner cream, one option for the conditioner step. 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.

Sources

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