Hide: Leathermaker's Calc

Free thread-length calculator. Hide Pro unlocks saddle-stitch SPI, edge / glue / dye matrices, brand presets. Stohlman + Armitage by name. Pay once at $6.99.

Hide is a leatherworking calculator with cited math. Every SPI, every thread-length rule, every edge-finish recommendation names its source. Pay once at $6.99 for Hide Pro — no subscription, no ads, no scanner.

The wedge

Most leatherworking apps stop at thread length. Hide includes thread length in the free tier (matches the incumbent's full surface) and unlocks the rest with one $6.99 lifetime purchase: saddle-stitch SPI by leather weight × project, edge-finish recommendation by leather temper, glue selection by use case, dye + sealant by goal, brand-aware presets. Every method tells you whose method it is.

Free tier

• Thread-length calculator — Stohlman's precision rule and Armitage's generous heuristic, side-by-side, with the leather-thickness math shown • Leather weight oz → mm thickness conversion (1 oz ≈ 0.4 mm per Tandy convention) • 1 saved project slot • Brand picker showing the supplier names

Hide Pro ($6.99 lifetime)

• Saddle-stitch SPI by leather weight × project type, with awl-hole spacing in mm / inches • Edge-finish matrix — burnish with water + gum tragacanth, burnish + Tokonole wax, edge paint, or wax burnish — selected by leather temper (veg-tan smooth, veg-tan thick, chrome-tan, bridle, oil-tan) • Glue selection matrix — contact cement vs EVA white vs PVA vs hide glue — by use case + dry time + odor • Dye + sealant matrix — spirit / oil / water dye, Resolene / acrylic / wax sealant, with compatibility warnings • Brand-aware presets: Tandy Leather, Buckleguy, Maverick Leather, Wickett & Craig, Horween — typical SKU ranges + edge-finish recommendation per their leather chemistry • Unlimited project log • Citations & Sources screen with every author named

Honest authority story

Leatherworking has no USDA / AOCS / Knife Steel Nerds equivalent. Hide's authority is practitioner-tier, and we own that: Al Stohlman (The Art of Hand Sewing Leather, Tandy 1977), Nigel Armitage (Armitage Leather, UK), Stitchpunk (J.H. Sherman), Corter Leather & Cloth (Eric Heins), plus tannery technical sheets from Wickett & Craig, Horween, and Sedgwick & Co. Every number Hide displays tells you whose method it is so you can verify against the original.

The Moon Dog promise

• Pay once. No subscription. No ads. • No account. No login. No signup. No network. • Works fully offline. • No data collection.

Disclaimer

Hide is for hobby leatherworking guidance. Independent verification against your supplier's technical sheets and your own project requirements is your responsibility.

© 2026 Roman Kopaliani