A Failure-Led Investigation

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Prototype #4 failed before it was ever assembled. What followed wasn’t a simple fix, but an investigation into leather bookbinding tolerances and how narrow spacing, tool limits, and material choices interacted under constraint. This piece documents that failure and what it revealed about craft, systems, and learning.

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On February 06, 2026, Prototype #4 categorically failed before it was assembled. Oof, that hurts. Instead of licking my proverbial wounds, I'm going to walk you through 1) What I thought the problems were. 2) Why they looked simple at surface level. 3) How multiple, reasonable decisions began interacting, revealing a deeper systems problem.

Alongside those, I'll attempt to answer why something that looked straightforward required so much investigation.

The First Symptoms

Cut Uniformity, Structural Integrity, and Leather Rigidity

Leather Type: 5 ounce, Veg Tan, 2mm thickness

Friday was a solid day at the benches. I followed through with the decision to scrap Template #4 and made a new template that addressed a width shortage I discovered. Template #5 would be my most accurate yet, from a certain point of view. Templating aside, the first symptom:

• Cut Uniformity = Blade Flex Though subtle and not throughout, the edges in spots where I recall readjusting pressure application has a gentle but noticeable decline. Not so much where cutting was comfortable and slowly executed.

• Structural Integrity = Hole Alignment & Tolerance Utilizing the same binding width I established in Prototype #3 (P3), comically, the same symptom presented itself in P4; 1 mm holes at 1 mm tolerance between them is difficult for me to maintain by hand with a single punch. A fraction off and the holes are too close together, undermining the integrity of the leather. In Prototype #3, I pressed on for practice sake and discovered tightening the thread tore the leather between station holes. I assumed thicker leather would ultimately solve this problem In P4. Hmm.

• Leather Rigidity = Fold Resistance This most recent acquisition of 5 ounce leather is the thickest I've worked with. I immediately noted the stiffness and that additional processing may be required to address the hinges post-binding width. I recalled a video in which the bookbinder utilized a V-gouger to lighten the hinges. More on this later. Do not proceed to v-gouging without reading further.

Note: I have one additional tool-related symptom to share which I will expound on independently later.

P2 (left), and P3 (right) —Both: 192 pages of 118 gsm paper— P2 = 12 signatures, P3 = 6 signatures

Cut uniformity and structural integrity issues were present primarily in Prototype #3 (P3). Prototype #2's (P2) binding width and hole-to-hole tolerance was much wider; leather, the thinnest I've used. It continues to be a solid piece of early conceptual work. My primary response to P2 in P3 was to narrow the binding width considerably which, as seen pictured above, has a low-tolerance for inaccuracy.

I recognize with you, dear reader, we've traversed a considerable amount of context, so what does it all mean, Basil?

• P2 worked because

  • the tolerance was wide; small inaccuracies could be tolerated without structural consequences.

• P3 struggled because

  • tolerance narrowed substantially; reduced margin for error made precision critical.

• P4 failed because

  • increasing the leather thickness was presumed to build resistance against tearing without revisiting

    • (A) design decisions; including binding dimensions and tolerances

    • (B) implementation limits; specifically single hole-punching accuracy within those designs decisions.

Once I defined this causal relationship, the next question I asked myself is "Did I consider this, or a similar outcome, and proceed anyway?" Likely. I'll qualify the validity of that question later.

Regarding V-gouging

As it turns out, that caution was warranted. Investigation showed that v-gouging at the spine achieves flexibility by cutting a channel through the leather’s thickness, severing continuous fibers along the hinge line. While this does allow the cover to fold more easily, it does so by concentrating stress at the thinned groove and permanently weakening the very area responsible for bearing opening and closing forces over time. For books intended to be handled, opened repeatedly, and age predictably, using this methodology at the spine is not an acceptable trade-off for me. Flexibility gained this way comes at the cost of durability.

When Secondary Effects Matter

Now we both can see clearly what the evidence is telling us. Each issue I addressed behaved reasonably on its own, as evidenced in P2, but the moment tolerances narrowed those issues began to merge. Blade flex affected cut consistency; single hole-punching and minor alignment errors undermined structural integrity under tight spacing. That's it. That's the inner-workings of this system map.

Earlier, in the First Symptoms section, I noted one additional tool-related observation. Now is the appropriate place to document it, as it falls just outside the system map described above.

As Secondary Problems Present Themselves

As you and I work at the workbench of the mind, let's remind ourselves of the design: 1 mm holes, 1 mm between them. As I recall, it took some doing to find an appropriately priced-for-practice punch at a 1 mm diameter. That's not to say they were difficult to find as much as my inexperience required learning alongside weighing practical costs; essentially, the right tool at the right price.

The methodology went something like this:

1. Keep initial costs low, but never for the sake of functionality. Tools must perform their function consistently so skill growth can increase.

2. Buy what is needed for the task at hand. Expand tool set as the emergence of new problems require.

In Prototype #4 (P4) a new problem did indeed emerge. To orient us at our shared mental workbench, when punching holes, research informed me that one punches from the flesh side (meaning the interior facing side) to the hair/top side. Punching in this way ensures the cleanest cut.

In P4's case, there's a manifestation of a sort of mushrooming effect on the top side around each hole. From what I can reasonably conclude, this effect brings with it some tearing on the interior of the hole closest to the Top's surface. The cause? Another reasonable conclusion could be: my hole punch is dull. Yep, just dull from practicing with it, good honest use and good, honest inexperience.

Now, reader, when we return to the system we mapped out above the symptoms are exacerbated by.... drum roll please... a dull hole punch. This is not a direct cause, nor does it belong inside the system map itself. But under low-tolerance conditions, it becomes a non-trivial amplifier, so to speak.

Proceeding Without a Complete Model

Once I defined the causal relationship, a more uncomfortable question followed: "Did I consider this, or a similar outcome, and proceed anyway?" Likely. But answering that honestly requires separating what I could observe at the time from what I could observe over the passage of time.

What that means, in the context of this post, is best described by restating point two from the methodology mentioned above: buy what is needed for the task at hand; expand the tool set as new problems emerge.

Let's begin with the last issue we discussed, the dull punch. I knew at the time of purchase it would become dull and, in turn, require sharpening. What I lacked was the experience to understand when and why sharpening becomes critical. Now, I’m familiar with both the evidence and the practical experience that demonstrate it. Is that failure?

After learning from Prototype #2 (P2), I redesigned P3 with a tighter binding width and in P4 increased the leather weight to 5 ounce. What I didn't know is how all these decisions would culminate. I concluded I would push the design to failure and learn from what broke. But if you can foresee and prevent failure, and choose not to, isn’t that itself a failure?

Practice over perfection.

We could follow this line of reasoning until the chickens come home to roost, but it’s worth pausing here, reader, to examine how each of us responds to the messiness of hindsight. Why? Because when we look back on a decision, our brains tend to judge it based on how it turned out rather than on the reasoning we had at the time.

Psychologists call this outcome bias or hindsight bias, and it can distort our view of what was reasonable. At the same time, people’s internal reward and punishment systems, how we economically and emotionally reinforce success and avoid failure, can subtly rewrite our stories about ourselves after the fact. What seemed like a sensible choice can become, in hindsight, a mistake we “should have seen coming.” Just a small thought between us, dear reader.

Sharpening the Point

When I started bookbinding in September '25, I met a fellow aspirant bookbinder and maker who goes by the name txtual. Early in our interactions, from one or both, the above quote Practice over perfection came to be and acts to this day as a reminder; approach learning with curiosity not self-judgement.

Another friend of mine, Tahoe Anime has lent me a wealth of expertise in craft and makery. It was Tahoe who reiterated the importance of well-maintained tools and how the right ones help us meet problems we face with honesty and confidence.

These are just two of many people who have offered up their support, openly shared their knowledge without expectation, and in their own ways remind me that shying away from mistakes was never the agreement; that was never the goal.

Onward

Was this written to bring about some catharsis in the face of failure? Perhaps. If so, it’s because I agreed with myself to enjoy learning a skill of my own choosing, in my own way, and to do so without allowing hindsight to corrupt that process.

Documenting both the technical and human sides of this work isn’t meant only for me, but for you as well, dear reader. Especially for those, like me, who practice a skill not for monetary gain, but for the simple enrichment of their own humanity.