When I needed more protractors, set squares and angle measurers in my classroom, I scanned one of each into a computer and then printed the image on to overhead projector film. (You can fit four conventionally sized protractors on to one A4 sheet.) Then I laminated and guillotined as necessary. I soon realised that the flexibility for resizing images in software packages meant I could make angle-measuring tools in an infinite variety of sizes. You can make a set of protractors which suit your own worksheets or textbooks. Pupils can read measurements more easily as you can ensure the text of the protractor falls over white space rather than text or coloured backgrounds. You can mask out one set of numbers to help make children's first experiences with angle measurement easier, or to differentiate your resources for pupils who need more help. You can create protractors to use for large-group "show me" exercises while individual pupils use smaller tools at their desks and then move to a classroom OHP in order to share their work with the rest of the class. I've made A3-sized versions to use with brightly coloured board pens when modelling techniques in front of the whole class.
Deputy head (curriculum), Bute House Preparatory School, Hammersmith, London