Patreon for knife sharpening creators — 2026 guide

Abrasive progression aluminum oxide diamond ceramic leather strop, included angle and burr apex formation, BESS edge testing, steel carbide size vanadium vs chromium carbides, sharpening angles by use category, and the Apple Tax.

Knife sharpening Patreons retain when they deliver the abrasive science and metallurgy layer that restoring-a-dull-knife videos and the-edge-I-got guide posts structurally omit: abrasive mineral hardness and grit progression, the mechanics of wire edge (burr) formation and apex confirmation with the Sharpie marker test, BESS edge testing methodology, steel carbide type and size and why they determine which abrasives actually cut the steel, and sharpening angle selection by use category. Plus the Apple Tax for knife sharpening audiences starting November 1, 2026.

Abrasive progression: aluminum oxide, diamond, ceramic, and leather strop

The abrasive sequence used to sharpen a knife is a series of controlled abrasion steps, each removing the scratch marks from the previous grit and refining the apex toward a finer edge. Aluminum oxide (Al2O3, corundum): Mohs hardness 9; the dominant abrasive mineral in whetstones, sharpening stones, and sandpaper; effective on carbon steels and most stainless alloys; Shapton Glass stones are Al2O3 in a glass-bond matrix, available from 120 grit (coarse, used for severely damaged or reprofiled edges) through 220, 320, 500, 1000, 2000, 4000, 8000, and 16000 grit (mirror-polish, used for straight razors and very hard steels); Japanese water stones use a clay-bond matrix that wears continuously to expose fresh abrasive but requires frequent flattening. Diamond plates: monocrystalline or polycrystalline diamond (Mohs 10) in a nickel-bond matrix on a steel plate; effective on all steels including high-vanadium steels where Al2O3 loads rapidly; available continuous (uniform surface) or interrupted (perforated or mapped surface that reduces swarf loading); primary abrasive for reprofiling and for sharpening vanadium carbide-rich steels like S90V, K390, and Rex 121 where Al2O3 stones cut slowly and load quickly. Ceramic rods and sticks: sintered aluminum oxide or silicon carbide in rod form; primarily used for touch-up (maintaining an apex without removing metal) between full sharpenings; aggressive enough to realign a rolled edge but not aggressive enough for reprofile; the standard for field sharpening kitchen knives. Leather strop with compounds: final step; removes the residual wire edge (burr) and refines the apex by deburring on the leather fibers; compounds specify abrasive particle size: chromium oxide (Cr2O3, green) 0.3–0.5 μm; iron oxide (red rouge, Fe2O3) 2–3 μm; diamond compound available at 0.1, 0.25, 0.5, 1.0, 3.0 μm; stropping direction is spine-leading (draw the blade edge-trailing across the strop, alternating sides) to avoid catching and rolling the apex back into a burr.

Wire edge (burr) formation and apex confirmation

As abrasive removes metal from one bevel and works toward the apex, the apex thins until the remaining metal cross-section can no longer support itself; the thin wire of remaining steel bends over to the opposite side of the blade as a wire edge (burr). A wire edge can be detected by drawing a fingernail or thumb pad across the edge (not along it) from the flat face of the blade: you will feel a slight catch or drag where the wire edge protrudes. A knife that has been sharpened on one side only until a full wire edge forms on the other side is at the correct point to switch to sharpening the other side. Sharpie marker test (apex confirmation): apply a permanent marker (black or blue) to both bevels along the edge, coating the bevel surface completely; sharpen 2–3 strokes on each side; examine the edge under magnification. If the marker has been removed uniformly from the bevel from the edge up to the secondary bevel line, the stone is contacting the full bevel and removing metal at the apex. If marker remains at the very edge (leaving an unsharpened strip at the apex), the angle is too acute (you are sharpening behind the apex). If marker remains in the middle of the bevel (behind the apex and behind the scratch area), the angle is too obtuse. The marker test is the calibration step for establishing the correct sharpening angle before committing to a full progression. Deburring methods: leather strop (most common; a few edge-trailing passes remove the wire without creating a new burr); cork or balsa wood (gentler than leather; appropriate for very thin hard edges); edge-leading passes on high-grit stone (removes the wire by cutting it off at the apex rather than bending it; produces a toothier micro-serration that works well for food cutting); progressive alternating strokes (alternate one stroke per side, reducing stroke count: 10/10/10 → 5/5/5 → 3/3 → 2/2 → 1/1 → strop).

Steel metallurgy: carbide type, carbide size, and abrasive selection

The abrasive required to sharpen a specific steel depends on the hardness and size of the carbide particles that reinforce the steel matrix. Carbide hardness determines which abrasive can actually cut the carbide vs. simply skipping over it; carbide size determines the finest edge geometry achievable in that steel. Chromium carbides (Cr23C6, Cr7C3): Mohs ~7.5–8; softer than Al2O3 (Mohs 9); conventional aluminum oxide whetstones can sharpen steels with primarily chromium carbides (440C, VG-10, AUS-8, Shun's SG2 in some configurations); these steels also respond well to ceramic rod touch-ups in the field. Vanadium carbides (VC): Mohs 9–9.5; harder than or equal to Al2O3; steels with vanadium as the primary carbide former (CPM S30V ~4% V, S90V ~9% V, K390, Rex121, M390/20CV/CPM 20CV ~4% V) require diamond abrasives for efficient material removal; Al2O3 stones will sharpen these steels but very slowly and with significant stone loading. Carbide size: conventional high-carbon steels and budget stainless steels produced by cast-and-wrought processing develop large carbide clusters 50–200 μm; CPM (crucible particle metallurgy) and PM (powder metallurgy) steels have carbide sizes 2–15 μm because the rapid solidification of atomized powder freezes the carbon in place before large carbides can grow; smaller carbide size allows a finer, keener apex because the carbides cannot form “micro-chips” at the edge when individual carbide particles are smaller than the apex radius target. A CPM steel at 62 HRC with 5 μm carbides will hold a 0.5 μm apex geometry that a conventional stainless at the same HRC with 80 μm carbides cannot hold because the large carbides chip out at scales larger than the apex radius. Steel HRC and sharpening feedback: steels at HRC 58–60 (most Western kitchen knives: Wusthof, Henckels, Global) are relatively easy to deburr and respond to ceramic rods; steels at HRC 62–64 (VG-10, SG2, AUS-10) require more strokes per side but deburr cleanly on a strop; steels at HRC 64–66+ (ZDP-189, HAP40, M390 at maximum hardness) require careful, consistent angle-holding because the very hard edge is brittle and will micro-chip if the sharpening stroke lifts off angle at the end of the stroke.

Sharpening angle selection by knife use category

Western kitchen knives (chef's knife, slicer, bread knife): 15–20° per side; the 15–20° range reflects the need for a robust edge that resists lateral stress on cutting boards during rocking cuts; thin protein slicers may go to 12–15° per side on hard Japanese steels but 15° is the minimum practical angle for soft stainless knives without immediate apex roll. Japanese kitchen knives (yanagiba, usuba, deba, gyuto in super steel): 10–15° per side; requires HRC 62–66+ to maintain such an acute angle; single-bevel traditional Japanese knives (yanagiba, usuba) are sharpened flat on the front face (0° approach) and the back face maintains a slight hollow-grind; the included angle is 10–15° determined by the front bevel only. Outdoor, hunting, and bushcraft knives: 20–25° per side; must survive lateral stress, prying, batoning, and scraping tasks that would roll or chip a kitchen knife edge; the convex secondary bevel common on many full-tang outdoor knives also distributes edge stress more effectively than a hollow or flat grind. Straight razors: 10–16° per side (very acute); always hollow-ground from the factory; maintained almost exclusively by stropping (adds 0 metal removal) with occasional touch-up on a natural stone (Belgian Coticule, Japanese Nagura slurry stones); the final apex is at 0.1–0.3 μm radius, confirmed by arm-hair test (shaves hair without catching) and sound (whisper-quiet shave with zero dragging sound).

The Apple Tax — knife sharpening creator iOS exposure

Knife sharpening content reaches audiences through YouTube tutorials, Instagram product photography, and specialty communities (KnifeForums, BladeForums, r/sharpening), which skew more desktop/Android than purely social platform niches. YouTube sharpening: 45–60% iOS; Instagram knife photography: 65–75% iOS; TikTok sharpening: 65–78% iOS. At $200/month at 52% iOS: approximately $31.20/month ($374/year) to Apple starting November 1, 2026. At $350/month at 58% iOS: approximately $60.90/month ($730/year). At $500/month at 62% iOS: approximately $93/month ($1,116/year). The web-only fix: direct subscribers to a web browser subscription URL or a KeepTier custom membership page. Stripe web transactions do not involve Apple; the creator keeps 100% minus Stripe fees.

Calculate your exact Apple Tax at keeptier.com — two inputs, one button, zero email capture.