A rack is a gear with infinitely many teeth, so its tooth form is the ISO 53 basic rack itself. There is no ratio here, only travel per turn.
| Travel per revolution | 125.6637 mm |
| Travel per tooth | 6.2832 mm |
| Travel at 20 rpm | 41.89 mm/s |
| Axis height | 20.000 mm |
| Usable stroke | 56.53 mm |
| Transverse pitch | 6.2832 mm |
| Transverse pressure angle | 20.000° |
| Rack addendum / dedendum | 2.000 / 2.500 mm |
| Root fillet | 0.760 mm |
| Tooth thickness (pitch / tip) | 3.142 / 1.686 mm |
| Contact ratio ε_α | 1.769 ok |
| Overlap ratio ε_β | 0.000 |
| Tip clearance | 0.500 mm |
| Pinion ⌀ (ref / tip) | 40.00 / 44.00 mm |
Nominal geometry, for machining or resin. Every surface moves in by this much, so teeth get thinner and bores get wider from the one number. It applies to STL only; STEP keeps the nominal geometry, because a CAD file that carries one printer's shrinkage is wrong everywhere else.