Bevel
A bevel is the angled surface ground onto a punch or blade edge to form its cutting geometry, where the angle trades sharpness against edge strength.
- 1Bevelled tip — grinding consistency decides how cleanly it enters
- 2Cannula; the graft passes through this bore, so its finish matters
- 3Hub seats in the pen — concentricity here controls depth accuracy
A bevel is the angled surface ground onto the tip of a punch or blade to bring two faces together into a cutting edge. The bevel angle — the angle between that ground surface and the instrument axis or the opposing face — is the geometry that decides how the edge behaves: a shallow, low-angle bevel is keener and slices with less force, while a steeper, higher-angle bevel is blunter but stronger and more resistant to rolling or chipping. Bevel is therefore not decoration on an edge; it is the edge's defining specification.
Bevel in practice
On an FUE punch, the bevel can be ground on the outside of the wall, on the inside, or from both sides, and each choice moves the cutting circle and the coring behaviour. An outside bevel keeps the lumen at full diameter to the very tip, protecting the graft, but places the sharp corner at the outer wall. An inside bevel narrows the tip and can core more aggressively. A double bevel splits the difference. The angle interacts with wall thickness: a thin wall cannot carry a very shallow bevel without becoming fragile, so bevel and inner-versus-outer-diameter are linked decisions.
The same logic governs blades. A sapphire or steel blade's incision quality — clean walls, predictable depth, minimal drag — comes largely from the ground bevel and its symmetry. A well-formed bevel produces a crisp cutting edge; a poorly finished one leaves burrs or an uneven apex that tears rather than cuts.
What buyers and professionals should know
Bevel angle is rarely printed on a spec sheet, which is a gap worth closing before you buy. When two punches or blades feel different in tissue despite sharing a diameter, the bevel is often the reason, and you cannot compare instruments you cannot describe. Ask the manufacturer for the bevel type (inside, outside, or double), the nominal angle, and how consistently it is held across a production lot — bevel consistency, not just its nominal value, separates a controlled grind from a variable one.
Bevel also shapes lifespan. A keen, low-angle edge dulls or chips sooner under the same use than a more robust geometry, so bevel choice ties directly into single-use-versus-reusable economics. The full treatment of how edge form drives cutting behaviour is in the punch edge geometry guide, and related coring and instrument context sits in the FUE punches hub. Treat bevel as a first-order question you raise with the supplier, not an afterthought.