Zen-Wu Z-1 Straight Edge

A precision straight edge for checking plane soles and other flat surfaces.

Aluminum-magnesium alloy body, machined through three stages of heat treatment to relieve stress at each step: raw material, rough machining, and finishing. The surface is hard-anodized in black, 30μm film thickness, with a surface hardness of approximately HRC60.

Straightness tolerance: 0.007mm (less than 0.3 thou). Surface finish: RA=0.06μm.

Two working sides: one with a relief notch for checking plane soles where the blade protrudes through the mouth, the other for general flat-surface and alignment checks.

Comes with a hand-stitched leather case.

Discontinued. Its successor, the Z-1T Straight Edge, moves to a titanium body: rust-free, abrasion-resistant, the same 0.007mm straightness. The Z-1 is now sold out.