282 APPLIED SCIENCE 



8. Explain the manufacture of a file. 



9. What is the mechanical principle of a file? 



10. What is the difference between a file and a rasp? 



11. Draw a sketch of a file. Name the principal parts. 



12. Name the different kinds of drills and the shape and pro- 

 perties of each. 



13. Explain the mechanism of a drill point? 



14. Is it possible to drill a hole to exact diameter? Why? 



15. What is reaming? 



16. What effect will irregular motion have in reaming? 



17. Why is it necessary to use oil or some lubricant when ream- 

 ing wrought iron or steel? 



18. What is corundum? Describe some of its physical properties. 



19. Why is it necessary to have a special difference in grinding 

 wheels for different metals? 



20. What holds the particles of a grinding stone together? Is 

 there any danger of the stone's breaking? 



21. What is emery cloth? 



22. Why are metals polished? Explain the operation. 



23. What is rouge? 



24. Explain the development of artificial grinding stones. 



