The 1–15 mm Hole Size Guide (That Actually Fits) — with the Yorkshine Punch Set

You don’t need twenty rules to get clean, comfortable holes. You need the right size logic, a steady workflow, and tools that don’t fight you. This guide keeps the focus tight: belts and watch straps—because that’s where 0.3–0.5 mm errors show up fast. Along the way, I’ll point out where the Yorkshine DC53 punch set (1–15 mm, wooden base) quietly makes the job easier—no hard sell, just the bits that matter in daily use.

The sizing rule that avoids 90% of problems

Start with the hardware, then add a tiny cushion for leather thickness.

Formula:
Hole Ø = Prong/Post Ø + 0.2–0.4 mm (thicker hides → closer to +0.4 mm)
Then test on an off-cut of the exact leather you’ll ship.

Why it works: prong/post is the constraint; leather thickness raises sidewall friction. That extra 0.2–0.4 mm prevents scuffing, ovals, and that annoying “pin chew” over time.

With the Yorkshine set you can grab 3.5, 3.8, 4.0 in seconds (no digging in drawers). The wooden base lays out 1–15 mm in order, so micro-tests don’t derail your flow.

Belts: hit the sweet spot (and keep it looking new)

• Hole diameter: most classic belt buckles land at 3.5–4.0 mm.

  • Slim prongs: 3.2–3.5 mm

  • Chunkier prongs: 3.8–4.0 mm

• Spacing: 25 mm (1") between holes. Clean visually, reliable in wear.

• Count: 5–7 holes, with the center hole as your “target” size; give ±2 for real life.

Comfort note: on 4–5 mm thick belts, that +0.2–0.4 mm cushion on the hole saves the edges from shaving when the prong enters at a slight angle.

Why the Yorkshine heads help here: DC53 steel (vacuum heat-treated, double tempered, 55–57 HRC) stays sharp, so the entry edge stays crisp. Crisp edge → true circle → less long-term ovaling.

Watch straps: tiny diameters, big difference

• Hole diameter: 1.8–2.5 mm covers most tang buckles.

  • Dress buckles / slim prongs: 1.8–2.0 mm

  • Sport buckles / thicker prongs: 2.3–2.5 mm

• Spacing: 6–7 mm—gives micro-adjust without clutter.

• Real-world tip: wrists swell with heat and activity. Place your “ideal” hole, then give +2 toward loose.

What you’ll feel: with small diameters, any slip shows. Yorkshine’s non-slip head design and the ergonomic handle mean you’re less likely to twist on impact—tiny detail, but it’s what keeps holes consistently round across a whole batch.

Technique that keeps holes round (and your sanity intact)

• Strike straight. If the force isn’t vertical, you’re making ovals.

• Let the waste move.

  • 1–9 mm Yorkshine heads are designed for direct waste drop-through—don’t pack the core.

  • 10–15 mm on thick hides? Clear every few hits. Tap from the shank side, not the edge, to avoid second impressions.

• Use a firm base. Too bouncy → mushy edges.

• Keep edges healthy. If you start seeing fuzz on entry, you’re dulling. Touch up early; don’t wait until the edge is gone.

The set’s blackened finish resists surface rust, so you’re not punching through micro-pitting. Sounds cosmetic; it isn’t—clean steel = clean entries.

Why DC53 & the Yorkshine build matter (in plain English)

• Edge life without chipping. DC53 at 55–57 HRC is a sweet spot: hard enough to hold an edge; tough enough not to chip if your strike isn’t perfect.

• Easy head swaps. The side-screw lets you change sizes fast mid-job (belt batch then watch straps, zero drama).

• Fewer mis-hits. Non-slip head + comfortable handle = better control, especially at 1.8–2.5 mm where any wobble prints.

• Time saved. 1–15 mm in one box, laid out on a wooden base. The real benefit isn’t “compact”; it’s “no hunting, no wrong size.”

What makers keep telling us:

• “Clean circles on veg-tan, even when I’m moving fast.”

• “Waste clears without the punch getting glued in small sizes.”

• “My wrist is happier after long sessions.”

(That’s the ergonomic handle doing its quiet job.)

A five-minute sizing workflow you can copy

1. Measure the prong/post with calipers.

2. Pick the nearest Yorkshine head and add +0.2–0.4 mm if the leather is thick.

3. Test on an off-cut: punch, insert hardware, flex.

4. Lock the size and run the batch; for belts, mark the center hole first, then step 25 mm each way.

5. Maintain: quick wipe, dry, light oil if you’re in a humid shop. The blackened finish helps, but water always wins if you ignore it.

Gentle close (use what you have)

Any well-made punch can get you there if you size correctly and test. If you want a set that covers belts to watch straps without guesswork, the Yorkshine DC53 1–15 mm punch set with the wooden base, non-slip heads, and quick side-screw is built to remove the little frictions—so your sizing logic shows up as clean, comfortable holes in the finished piece.

If you’d like, I can add a printable belt/strap hole-spacing template next (A4, with guides for 25 mm belts and 6–7 mm straps).