Hide: Leather Calculator — Support

Need help?

Email roman.kopaliani@gmail.com with your question. Please include:

• What you were trying to do
• What happened
• The iOS version and iPhone or iPad model you're using (Settings → General → About)
• The app version (Hide → Settings → About)

Common questions

Why do you show both Stohlman's and Armitage's thread-length rules?

Because they disagree, and the disagreement is informative. Stohlman's rule (from The Art of Hand Sewing Leather, Tandy 1977) is precise — it accounts for leather thickness and the back-and-forth pull-through math. Armitage's heuristic is generous — it uses a flat 3× multiplier per stitch that accommodates real-world thread loss. For thin leather, Stohlman undershoots; for thick leather, Armitage overshoots. Showing both lets you compare and pick the rule that has worked for your past projects.

Why doesn't burnishing work on chrome-tan leather?

Chrome-tanned leather is tanned with chromium salts that lock the fibers against water uptake. Burnishing relies on water (or Tokonole) softening the fibers and friction polishing them flat. Chrome-tan fibers don't respond. You'll find this called out in Stitchpunk's edge-finishing reference and in Horween's own technical sheets for Chromexcel. Hide uses edge paint (Fenice, Giardini, or Beam) for chrome-tan and warns you if you pick a method that won't take.

Why does Hide cite Tandy for the oz → mm conversion?

Because "ounces of leather" is a US hobby convention (oz per square foot) and Tandy is the brand-anchor for the convention. 1 oz ≈ 0.4 mm. European tanneries quote leather thickness in mm directly; Hide's units picker lets you switch between mm and inches. The underlying math is the same either way.

How do I restore Hide Pro on a new device?

Open Hide → Settings → "Restore purchases". This re-validates your Apple ID's purchase history with the App Store and unlocks Hide Pro features if your ID owns the purchase. Hide Pro is a one-time, non-consumable purchase tied to your Apple ID, not a subscription.

Does Hide work offline?

Yes. The app has no network calls. Every data table (SAP — saddle-stitch pitches, edge-finish recommendations, glue selection, dye guidance, brand presets) ships as Swift literals in the bundle. The only network call StoreKit makes is for the purchase itself when you tap "Unlock — $6.99".

App Privacy

See the Hide Privacy Policy. The app collects nothing.