Hems, jogs and safety edges: finishing an exposed sheet edge

A clean edge is still a sharp edge

A fiber laser leaves a crisp, square edge — and square metal is sharp. On anything a person picks up, leans on or reaches into, that edge is a snag and a cut waiting to happen. A hem folds the edge back on itself, so the exposed face becomes a rounded fold instead of a raw cut. It does three jobs at once: takes the edge off, stiffens the panel, and hides the cut face.

Open or closed

A closed (flat) hem folds the edge fully back against the panel — the neatest, but it works the metal hard and can crack on thicker or less ductile material. An open (teardrop) hem leaves a small rounded gap at the fold; it’s gentler on the material and the usual choice on anything but thin, soft sheet. A rolled or safety edge curls the edge into a tube for the most rounded, snag-free finish.

Thicker or springy material (stainless, 6061) leans toward open or rolled — a closed hem may crack.

Give the hem enough to grip

The folded-back leg has to be long enough for the brake to form it — too short and there’s nothing to hold. As a safe minimum, keep the return at least about four times the material thickness. It’s the same idea as a minimum flange: the tool needs something to work with.

Jogs let panels overlap flush

A jog (or joggle) is a small double-bend that steps a panel by roughly its own thickness, so a lapping panel can sit flush instead of proud. It’s how two overlapping covers finish level, or how a lid drops into a rebate. Cheap to add, and it turns a stepped, catchy joint into a clean continuous surface.