Rebated Edges & Safe Tips: Grinding the Not-Sharp

A rebated edge is a manufactured shape, not an absence of sharpening — a specific flat-and-radius geometry that must pass a tournament marshal’s gauge and survive a season of steel-on-steel. Grinding not-sharp to spec is honest precision work. Here is how it is done on a 2×72.

THE SHAPES, DEFINED

Three elements make a combat blunt. The edge flat: the deliberately thick edge — buhurt’s floor is about 5/64 inch (2 mm per rulebook) and working practice runs comfortably above the minimum, since edges thin as they peen and dress over a season; build at 1/8 inch and inspections never argue. The edge radius: the flat’s corners rounded into the bevels — buhurt wants radii beyond roughly 3/8 inch (10 mm), meaning the edge reads as a smooth rounded landing, not a squared curb. The tip: rounded, substantial, and in thrust-permitted scenes (HEMA, SCA rapier) engineered to flex or capped per the org — a spatulated or button tip ground full and smooth, never a filed-off point. Every number above is the published ballpark for its scene; the current rulebook and the marshal’s gauge are the real spec, per the combat blunts map.

GRINDING THE REBATE

Sequence on the 2×72: grind the blade’s bevels as designed but stop the edge at the target flat plus dressing allowance — a platen pass with the blade held square, checked with calipers along the full length (inspectors measure the thin spot, not the average). Then convert flat-plus-corners into the radius on the slack belt: rolling passes that wrap the flat into the bevels until a fingertip slides across the edge and feels one continuous curve — the same muscle memory as convexing a working axe edge, aimed at a bigger radius. Tips shape against the platen edge and small wheel: full-width button first, then blended into the profile so no shoulder catches a gauge or a gambeson. Finish matters more than it looks: a 220-grit-clean rebate peens smoothly in service; a rough one grows the burrs that fail inspections.

SPRING STEEL DISCIPLINE

Combat blunts are 5160/9260-class at resilient hardness (per the spring steel guide), which means the grinding happens on tempered spring steel: sharp belts, moderate speed off the speed chart, and heat discipline — a blued rebate is an over-tempered soft spot that will mushroom first at the next tournament. The thick edge is more heat-tolerant than a knife edge; it is not immune.

MAINTENANCE: THE SEASON’S ARITHMETIC

Steel-on-steel service peens edges, raises burrs and slowly thins flats — which is why fighters dress their weapons and re-inspect all season. Build for it: start above minimums, leave tips generous, and offer re-dressing as a service (a slack-belt session restoring radius and removing burrs is fast work and repeat business). Retire lines exist too: a blade dressed down to the rulebook floor, or showing crack ticks at the flat, is done — say so to the customer; the marshal will anyway.

WHAT THIS MEANS AT THE BENCH

Calipers on the flat, fingertip on the radius, gauge-thinking throughout, and the current rulebook taped over the bench for the scene you are building into. Not-sharp to spec is real grinding craft — and the maker known for passing inspection the first time owns the club’s equipment budget.