Key, 5x18 mm

I was worried the key might be slightly oversized, but it slid right into the spindle slot on my mini mill with zero fuss. It measures exactly 5x18 mm, just as described, and makes reassembly feel solid.

Finally, a key that actually sits flush in the 5x18 mm slot without any play—the fit on my mini lathe's motor pulley is spot on.

Worked perfectly to secure the spindle on my R8 mini mill — the 5x18 mm sizing was exactly right, no filing or fitting needed. Also popped it on the motor pulley of my lathe with the same smooth result. Solid little key for the price.