To cut thin stainless steel shim stock (0.005” or about 0.13 mm) without curling, you need to minimize lateral stress and heat, both of which cause distortion. Here’s how to do it effectively.

First, support the material fully. Place the shim flat on a clean, hard surface like a sheet of mild steel, aluminum, or thick acrylic. Do not let any part overhang. Use double-sided tape or low-tack spray adhesive to temporarily bond the shim to the backing plate. This prevents lifting during cutting.

Second, choose the right tool. Avoid standard scissors or tin snips—they push metal on either side of the blades, creating waves and curls. Instead, use a sharp utility knife with a new blade, or better, a scalpel or etching knife. For straight cuts, a razor blade guided by a steel straightedge works well. For circles or complex shapes, use jeweler’s saw or a very fine-tooth coping saw (32 TPI or higher). Laser cutting is ideal if available, as it produces zero mechanical stress.

Cutting technique is critical. When using a knife, make multiple light passes along the same line, increasing pressure gradually. Do not try to cut through in one pass—this causes blade deflection and uneven stress. For a saw, clamp the shim between two sacrificial sheets of thin plywood or acrylic (a “sandwich”) before cutting. This damps vibration and prevents the saw teeth from grabbing and curling the edge.

After cutting, do not bend or snap the piece off. Small burrs can be removed by laying the shim flat on a smooth stone or fine sandpaper (600 grit) and sliding it in circles under light finger pressure. Never use a file or deburring tool on unsupported shim—it will roll the edge.

If curling still occurs despite support, anneal the shim stock before cutting by heating it to dull red with a propane torch (only for non-heat-treated grades like 304 or 316), then let it cool slowly. This softens the material and reduces internal stress that causes curl. Alternatively, purchase “dead soft” shim stock, which is far less prone to curling than half-hard or full-hard stainless.

Finally, store cut pieces flat between cardboard or in a rigid sleeve. Even the act of picking up a finished 0.005” shim can curl it—slide it off the cutting surface onto a stiff sheet of paper.