This is what Wartenberg pinwheel roller perforations look like:
The 7-row Wartenberg rollers (22 pins/wheel) I have make 44 perforations per square inch. Pinwheel diameter, pin-tip to pin-tip, is 1.125" (28.6 mm). Roller width is 1" (25.4 mm), pin-tip to pin-tip. Pin length is approx. 5-6 mm. Perforation hole diameter at the foam surface is approx. 1 mm. Space between perforation holes is approx. 4-5 mm.
