Custom rack gear

For turning rotation into straight-line movement

A toothed rack in the module you need, at the length you need. It turns the rotation of a pinion into straight-line movement: one revolution moves it by π × module × the number of pinion teeth. The flanks are straight because a rack is a gear with infinite radius —which is why it's the reference profile used to cut other gears— and it is made with the whole number of teeth that fit in the requested length, because they must stay on pitch or the pinion will skip.