TOOL GEOMETRY

# TOOL GEOMETRY

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## TOOL GEOMETRY

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##### Presentation Transcript

1. TOOL GEOMETRY

2. MACHINING WOOD • A Stress Failure Process With Three Objectives. • Severing – To make two or more pieces from one • Shaping – To impart a shape or contour on a piece of wood • Surfacing – Sanding, jointing or planing an edge or surface

3. MACHINING WOOD • The tools

4. MACHINING WOOD • The tools

5. MACHINING WOOD

6. MACHINING WOOD

9. MACHINING WOOD IDEAL CUTTING ACTION

10. MACHINING WOOD HERE IS WHAT HAPPENS Wood fails when ultimate stress is reached. Stress is accompanied by strain. The work piece deforms ahead of the cut and both work piece and chip spring back.

11. TYPES OF CUTTING ACTION • ORTHOGONAL CUTTING • PERIPHERAL MILLING

12. TYPES OF CUTTING ACTION • ORTHOGONAL CUTTING • The tool edge is more or less perpendicular to its direction of travel • The cut is parallel to the edge or surface of the board Examples: Pushing a hand plane across the surface of a work piece Using a cabinet scraper

13. TYPES OF CUTTING ACTION • Peripheral Milling – A rotary cutter head with one or more cutting edges intermittently coming in contact with the work piece • Jointer • Router • Planer

14. TYPES OF ORTHOGONAL CUTS 90° TO 0° - Planing along the grain 90° - Relationship of the cutting edge to grain 0° - Relationship of the direction of cut to the direction of grain

15. TYPES OF ORTHOGONAL CUTS • 90° to 90°Cutting (Planing End Grain) • Requirements for a good cut • Low cutting angle • Sharp edge • High clearance angle

16. TYPES OF ORTHOGONAL CUTS • A closer look at 90 to 90 cutting

17. TYPES OF ORTHOGONAL CUTS

18. TYPES OF ORTHOGONAL CUTS • The Effects of Skewing

19. TYPES OF ORTHOGONAL CUTS • O° TO 90° CUTTING VENEER SLICING

20. TYPES OF ORTHOGONAL CUTS • Type I Chip • Large rake angle • Small chip • Grain failure occurs out in front of the knife • Cutting angle ~ 45° sharpness  30° clearance  15°

21. TYPES OF ORTHOGONAL CUTS • Type II Chip • Smaller rake angle • Compression rather than upward lifting • Failure occurs right at the cutting edge

22. TYPES OF ORTHOGONAL CUTS • Type III Chip • 0° to small rake angle • Uses compression to produce failure • Snow plow effect Not an acceptable chip type

23. TYPES OF ORTHOGONAL CUTS CUTTING QUALITY

24. TYPES OF ORTHOGONAL CUTS When you can’t cut with the grain the chip breaker can help

25. TYPES OF ORTHOGONAL CUTS

26. TYPES OF ORTHOGONAL CUTS

27. PERIPHERAL CUTTING • Revolving cutterhead operating along an edge or face of a board • Creates knife marks which should number between 12 and 25 per inch

28. PERIPHERAL CUTTING

29. PERIPHERAL CUTTING • Jointer • Planer • Router • Refer to pages 166, 167 & 168 for peripheral cutting problems.

30. MACHINING WOOD

31. MACHINING WOOD • The tools

32. MACHINING WOOD • www.technologystudent.com/equip1/planes1.htm www.fine-tools.com/rauh.htm

33. MACHINING WOOD

34. MACHINING WOOD • Bench Chisels

35. MACHINING WOOD • Paring Chisel

36. MACHINING WOOD • Cranked Paring Chisels

37. MACHINING WOOD • Mortising Chisel

38. MACHINING WOOD • Mortising Chisels

40. MACHINING WOOD

41. MACHINING WOOD

42. MACHINING WOOD • Types of saw blades • Plywood or cross cut blade • 60 to 80 teeth • large top bevel • small gullets • Rip blade • 20 to 60 teeth • no top bevel • larger gullets

43. MACHINING WOOD • Combination blade • 40 teeth • Square tooth followed by beveled teeth • Large gullets • Laminate blade or “triple chip” blade • 80 teeth typical • Small gullets