NotAPinguin

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4 minute read

Based on the YouTube video “Picking The PERFECT Thread for Leatherwork” by Will Hodges.

Thread is the detail most beginners overlook — and yet it’s one of the most important decisions in any leatherworking project. Get it right and your work not only looks amazing, it lasts a lifetime. Get it wrong and you’ll feel it on every single stitch.

In the video, Will Hodges breaks thread down into three parts: thickness, material, and — most importantly — how to actually choose the right thread for what you’re making.

The Summary

1. Thickness — match it to the piece

Thread thickness is measured in millimetres, and the practical range for hand-stitched leather goods runs from about 0.45 mm up to 1 mm (beyond that you’re in shoemaking and industrial sewing territory).

  • 0.45 – 0.55 mm — the refined end. Perfect for small goods: card holders, bifold wallets, watch straps, little pouches. Will stitches card holders with 0.45 mm.
  • 0.65 – 0.85 mm — the bold middle ground. The stitch line is clearly visible and makes more of a statement.
  • 1 mm+ — heavy-duty: shoes, industrial work. A different world.

The general rule: thicker thread = bolder look and more strength (with the same material, the thinner thread breaks first under equal tension). If you want refined, go thin; if you want rugged, go thick.

The part beginners miss: thread thickness must be matched to your pricking iron spacing. A chunky 1 mm thread crammed through 3 mm holes won’t sit right and kills your stitch angles — and a 0.45 mm thread in 5 mm holes disappears completely. As a rule of thumb: a 3 mm iron pairs with 0.45 – 0.55 mm thread, while big 5 mm irons want something much thicker.

2. Material — polyester vs linen

There are two main manufacturing styles — spun (round, the one he prefers) and braided/flat (harder to stitch; needles keep piercing the thread). Within that, the two materials that matter:

Polyester — the modern choice. It’s more durable (plastic stretches under tension where linen snaps), stronger at the same thickness, and fully waterproof — perfect for anything living outdoors, like a saddle. It’s also far easier to finish: cut it short and melt the end with a lighter, whereas linen just burns to a crispy mess. Downside: it’s shiny plastic that doesn’t need waxing, and it won’t biodegrade.

Linen — the traditional craftsman’s choice and one of the first stitching materials ever made. Natural, matte, waxable, and biodegradable. Spun linen is round, so your needle glides through without splitting the thread — something he says he’s never had happen with linen, but constantly did with flat tiger thread. If you’re doing traditional fine leather craft, this is the look.

Bottom line: starting out or want easy finishing → polyester. Traditional fine work → linen. (He mostly uses spun linen himself.)

3. How to choose for your piece

Choosing isn’t one-size-fits-all — it’s a multi-factor decision:

  • Function & layers — how many layers of leather are you stitching through, and how much wear will it take? A card holder is four thin layers seeing light use → thin thread is fine. A belt carrying your body weight, or a piped bag edge (two layers of piping + exterior + lining, nearly a centimetre of leather) → you need a thicker, stronger thread. He’d never stitch a piped edge with 0.45 mm; that’s a 0.55 mm job.
  • Feel & finish — refined vs rugged, formal vs bold.
  • Looks — polyester opens the door to fun effect threads: multicoloured, glow-in-the-dark, UV, metallic. (He admits to ~50 spools.)

One comfort: the visual difference between 0.45 mm and 0.55 mm is 0.1 mm — unless you’ve been stitching for years, you probably won’t see it. Pick the one you like.

How to Choose — Workflow

Here’s the decision flow from the video, visualised:

flowchart TD A["Your leather project"] --> B{"1. Material — will it live outdoors / face water?"} B -- "Yes" --> C["Polyester
waterproof & strongest"] B -- "No" --> D{"Going for a traditional fine craft look?"} D -- "Yes" --> E["Linen
classic, matte, waxable"] D -- "No" --> F["Polyester
easiest to start with"] C --> G{"2. Size — how heavy is the wear & tension?"} E --> G F --> G G -- "Light — card holder, wallet" --> H["0.45 mm"] G -- "Medium — bag, piped edge" --> I["0.55 mm"] G -- "Heavy — belt, thick stack" --> J["0.65 mm+"] H --> K{"3. Check — your pricking iron spacing"} I --> K J --> K K -- "3 mm iron" --> L["0.45 – 0.55 mm"] K -- "4 mm iron" --> M["0.55 – 0.65 mm"] K -- "5 mm+ iron" --> N["0.8 mm+"] L --> O["Ready to stitch"] M --> O N --> O

Key Takeaways

  • Thickness = strength and style. Thin (0.45 – 0.55 mm) for refined small goods, thicker (0.65 mm+) for bold, hard-wearing pieces.
  • Match thread to your pricking irons. 3 mm irons → 0.45 – 0.55 mm thread; 5 mm irons → much thicker, or the stitching looks lost.
  • Polyester for durability and beginners (waterproof, melt-to-finish); linen for traditional fine craft (matte, round, needle-friendly).
  • Choose by function, feel, and finish — how many layers you’re stitching, how much tension the piece sees, and the look you’re after.
  • Perfection is unnoticeable — if the thread draws your eye, it’s probably the wrong one for the piece.

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