Sharpening angles

Angles. Pick the tool and the steel. You get the primary bevel (ground, or honed on a coarse stone) and the micro-bevel (the narrow secondary bevel honed on the fine stones), the included angle for knives and axes (which are quoted per side), and notes. The steel adjusts the advice: A2 chips at very low angles and gets a 2° steeper micro-bevel; D2’s coarse carbides get 3°; soft stainless knives go steeper and hard carbon ones a little more acute; high-vanadium and powder steels need diamond or CBN. For plane irons it works out the cutting angle — bed plus honed angle for a bevel-up iron, frog plus any back bevel for a bevel-down one — and warns if the clearance gets small. Drills give the point angle (118° or 135°) and lip clearance; the Lathe and chain tab has HSS tool angles for metal lathes by material and saw-chain filing angles and file sizes by pitch.

Honing guide. A roller guide sets the angle by how far the blade projects from it. With the stone as the baseline, the roller of diameter D touches it below its axle; the blade’s lower face sits on a seat h above the axle, so its back — the face that ends at the edge — is h + t away for a blade t thick. Walking up the back from the edge a distance s to the point nearest the axle, then across to the axle, must climb exactly the roller’s radius r = D/2:

where c is how far forward of that point the reference you measure from (usually the jaws' front face) sits. The inverse — the angle a given projection hones — is θ = atan2(h + t, P + c) + asin(r / √P + c)² + (h + t)². Measure D, h and c on your guide (Eclipse-style side-clamp guides and others), or calibrate: enter two projections and their angles (from the guide’s chart, or measured with the gauge) and it solves for h and c. The table shows each angle’s projection and what the same projection gives with a blade 1 mm thicker. A Veritas Mk.II has its own registration jig; this is for other guides, other angles and odd blades.

Templates. A projection jig: a base board with a lip for the guide’s jaws and one lane per angle with a stop block at that angle’s projection — a cut list and a 1:1 printable template to glue on. An angle gauge: a plate with a notch per angle (15–35° by default), each with one square flank and one at the angle, as SVG or DXF R12 to laser-cut from 3 mm acrylic or ply, or to print on card. And knife wedges, which stand on the stone for the blade to lean against. Print at 100% and check the 50 mm bar.

Grits. Convert between JIS (Japanese stones), FEPA F (bonded and loose), FEPA P (sandpaper), ANSI/CAMI and diamond plates through average particle size in microns — a #1000 stone is about 11.5 µm, P1000 paper about 18 µm. Type your stones in order and it flags jumps of more than about 4× in particle size; suggested progressions are given for repairs, routine honing, touch-ups and kitchen knives.

Knife sharpeners. V-rod sharpeners hone at the rods' angle from vertical when the blade is held plumb (tilt it and one side goes steeper, the other shallower); clamp-type guided-rod kits give atan(rise ÷ run), so the edge’s distance from the clamp changes the angle; pivoting-arm systems give asin(rise ÷ arm length). For freehand work, the spine height above the stone is the blade width × sin θ.

Related: woodworking angles for mitres and compound cuts, speeds and feeds for lathe and mill cutting data, and CNC router feeds and speeds.

The angles are the common recommendations of the toolmakers (Veritas/Lee Valley for PM-V11 and bevel-up planes, and plane and chisel makers' sharpening instructions) and of standard references on sharpening such as Leonard Lee’s The Complete Guide to Sharpening; ranges are given where practice varies, and your own results win. Grit sizes are from JIS R6001, FEPA’s F and P standards, ANSI/CAMI tables and DMT’s published diamond sizes; stone makers don’t all follow JIS, and above #8000 every maker has its own scale. Chain-filing values are the usual ones for cross-cut chain — the chain’s packaging or its maker’s chart takes precedence.

Any current browser. Printing a template opens a new window — allow pop-ups, and print at 100%.

Share link copies a URL that opens this tool exactly as you have it set up: the tool and steel, your guide’s dimensions, and the template and grit settings. Opening a link replaces your own saved settings for the tool; a Restore my settings button brings them back. To write a link by hand, use tool and steel — for example /tools/sharpening/?tool=chisel-bench&steel=a2.

Everything is worked out in the browser and kept in its local storage; nothing is sent anywhere.