Turning Tool Angle Calculator

Scrapers are ground at 70-80 degrees rather than a gouge's 30-55 degrees because they work by presenting a flat edge at center height and shearing or scraping rather than slicing along a rubbed bevel. The clearance angle output (90 minus the bevel angle) is what actually determines whether that blunt edge rubs cleanly or digs in, and it matters most for exactly this kind of tool geometry.

Scrapers get an ideal rest-below-center of zero, since they're presented flat at center height. Gouges instead get 0.5 inch below center when their bevel is steeper than 40 degrees, or 0.25 inch otherwise, because a gouge cuts by riding its bevel against the wood, and starting the handle lower lets you raise it during the cut to engage that bevel properly.

The wing angle only calculates for tool type 0 (bowl gouge), where it's set to the bevel angle plus 10 degrees. Sweeping the wings back to a steeper angle than the nose is what lets a bowl gouge shear-cut smoothly as it transitions across the curved interior of a bowl — the other tool types this calculator models don't use that swept-wing profile, so their wing angle reports as zero.

It's computed as 2.5 divided by the tangent of the bevel angle, a formula calibrated to a generic Wolverine-style pocket jig. Real projection depends on your specific jig's pivot arm length and pocket geometry, so this figure is meant as a starting reference to sharpen from and adjust — not a substitute for dialing in your actual jig setup with a test grind.

It's collected but doesn't currently affect the calculation — every output here (bevel angle, clearance angle, rest height, wing angle, jig projection) is derived from tool type, custom bevel, and center/rest height alone.