Rounded corner squares 2 mm - 2.9 mm pitch 0.1 mm

Squares with a radius in the corners, sides of 2 to 2.9 mm

Here both sides grow equally, so the shape stays a square across the whole series and only its size changes. The ten steps start at two millimeters and end at 2.9 mm, with one tenth lying between neighboring pieces.

Why a radius in the corner is not pointless

The pressed and milled hatches of real equipment always have rounded corners, because a sharp corner is a stress concentrator and is hard to seal. A mask with a sharp corner therefore leaves an outline that looks at first glance like a cut-out of paper. A radius also holds better when being peeled off and lifts less.

Which scales it suits

Two to three millimeters correspond in 1:72 scale to roughly fifteen to twenty centimeters, and in 1:48 to ten to fourteen. That is the size of instrument covers, small service hatches, anti-slip pads and the caps of filler necks.

The advantage of a square shape

Unlike a rectangle, a square needs no watching for orientation: turned ninety degrees it fits the same. When fitting a larger number of masks at once that speeds the work up noticeably and reduces the risk of a piece being laid upright instead of across. And when a shape does still have to be lined up against an engraved line, rest it on the straight edge of a ruler laid alongside.

• the sides grow together and the shape stays a square
• ten sizes in the range 2 to 2.9 mm
• the corners match the radius of real hatches