2. Chapter 13
Offhand Grinding

3. Objectives Identify the various types of offhand grinders.
Dress and true a grinding wheel.
Prepare a grinder for safe operation.
Baldor

4. Objectives Use an offhand grinder safely.
Describe the use of wet and dry grinders.
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5. Grinding Tasks Sharpening tools
Removing material too hard to be machined by other techniques
Cleaning parting lines from castings and forgings
Finishing and polishing molds

6. How Grinding Machines Work
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7. Offhand Grinding Use of bench, pedestal, or belt grinder
Work does not require great accuracy
Part held in hands and manipulated until ground to desired shape

8. Bench Grinder Fitted to a bench or table
Grinding wheels mount directly on motor shaft
Coarse
Fine
Baldor

9. Pedestal Grinder Larger than bench grinder
Pedestal (base) fastened to floor
Wet or dry
Tool rest supports work
Baldor

10. Safety Note Wear safety glasses
Be sure grinder’s eye shield is in place
Do not make tool rest adjustments while the grinding wheels are revolving

11. Tool Rest Position
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12. Abrasive Belt Grinders
Heavy-duty version of woodworking belt and disc sanders
Variety of abrasive belts
Grind to a line
Finishing cast and forged parts
Deburring
Contouring
Sharpening
American Foundrymen’s Society

13. Portable Hand Grinders
Flexible shaft grinders
Precision microgrinders
NSK America

14. Grinding Wheels Coarse abrasive grains bonded into circular shapes
Dulled abrasive particles wear away
Reveal new, sharp particles
Examine frequently for concentricity, roundness, and cracks
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15. Ring Test
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16. Wheel Dresser Trues wheel Provides better grinding surface
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17. Loading and Glazing Loading Glazing
Occurs when grinding soft metals
Small pieces of material clog wheel
Glazing
Occurs when grinding very hard metal
Grains dull before they can fall away
Both cause wheel to cut inefficiently

18. Grinding Rules Grind using face of wheel
Move work back and forth across face
Keep wheel dressed and tool rests properly adjusted
Grind soft metals on abrasive belt grinder when possible

19. Abrasive Belt and Wheel Grinder Safety
Make sure tool rest is properly adjusted
Wear goggles or face shield when grinding
Never operate while senses are impaired
Check machine thoroughly before using
Check wheel for soundness before putting on grinder
Do not use glazed or loaded wheel

20. Abrasive Belt and Wheel Grinder Safety
Be sure wheel guards and safety devices are in place
Hook up exhaust attachments if needed
Do not stand directly in front of wheel
Hold small work in clamp or hand vise
Avoid work pressure on the side of wheel
Keep hands clear of rotating wheel

21. Abrasive Belt and Wheel Grinder Safety
Never operate at speeds higher than recommended
Have injuries treated immediately
Allow wheels or belt to stop completely before making adjustments

22. Being an Efficient Employee
Workplace Skills
Being an Efficient Employee
Efficiency can always be improved
Examine methods you use
Are newer, better methods now possible?
Tips
Set priorities each day
Match tasks to energy levels
Organize the work environment

23. Using a Dry Grinder
Place work on tool rest and slowly push against grinding wheel
Avoid using too much pressure
Minimize overheating to avoid removing temper
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24. Using a Wet Grinder
Use slightly crowned face when grinding carbide-tipped tools
Use ample coolant at all times
Use entire face of wheel
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25. Adjusting the Clearance Angle
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