1. Metal Grinding

2. Terminology

3. Grinding Wheels
A grinding wheel is an expendable wheel that is composed of an abrasive compound used for various grinding and abrasive machining operations.

4. Grinding Wheels Many different styles available
Choose correct type & grit of wheel
Replace once when wheel reaches ½ of its original diameter.

5. Ring Test
Good – Ring
Bad – Thud
ALWAYS TEST WHEELS BEFORE INSTALATION

6. Wheel Identification Size: Grit : How aggressive the wheel will grind
10” x 1.5” x 1.25”
Wheel Diameter x thickness x arbor size
Grit : How aggressive the wheel will grind
Higher Grit = Smoother Wheel
RPM : How fast the wheel can spin safely
Use wheels that meet or exceed the grinder RPM rating!
Color:
Grey & Brown – workhorse grits, mild steels
Pink & White – harder steels that require cool grinding surface
Ruby Red – Tool steels and sharpening

7. COURSE GRIT WHEELS
Deeper cuts
More aggressive
0-24

8. FINE GRIT WHEELS
Sharpening
Finishing
Less aggressive cuts
grit

9. WIRE WHEELS Watch out for flying wires! Removes rust & paint
Rough Polishing

10. Polishing & Buffing
150 grit and higher
Cotton

11. Dressing a Grinding Wheel
Adjust tool rest to proper gap for dressing
Turn on grinder
Hook dressing tool on tool rest
Put light pressure on wheel while moving back and forth
Continue until wheel is smooth
Readjust tool rest to 1/16”
LINK

12. Don’t grind soft metals!
Aluminum, copper, brass, etc.
The metal is too soft
The heats up and melts into the grain
It will need to be dressed

13. Safety Rules:
Adjust tool rest to 1/16” MAX from wheel

14. NEVER GRIND ON THE SIDE! The sides are not trued during manufacturing
They are not even
The sides are not trued during manufacturing
Not designed to handle heavy loads.
May shatter leading to a very nasty result.

15. Safety Rules PPE – Glasses, shield, dust mask, ears
NEVER wear gloves!
Hold the piece with a locking pliers if it gets hot.
Stand to the side during startup
Inspect wheel
Re-Dress uneven or loaded wheels
Wear a mask
Keep rest 1/16” from wheel

16. Safety Rules: Hold work by hand or with a clamp or vice grip
Do not adjust or repair while grinder is running
DO NOT FORCE IT!
Keep your work piece on the tool rest at ALL times

17. Portable Disc Grinder Angle Grinder Hand Grinder

18. Types of Discs 1. Grinding wheel Weld preparation
Removing slag/unwanted welds
2. Fiber Cut-off Wheel
Metal cutting
Use at a 90 degree angle only
3. Flap Disc / Sanding Disc
Metal finishing
4. Cup brush
Used for removal of paint
Weld cleanup
Hold with EXTRA force!

19. Standard Discs
Used for grinding, de-scaling, polishing, blending, and finishing.
Semi-flexible backing
Fits curved & rough surfaces
Leaves a smooth & swirl-free finish.

20. Raised Hub / Type 27 Hub is raised in the center 1/8” thick ¼” thick
Light Grinding
Cutting off
Notching
¼” thick
Heavy duty grinding only

21. Saucer Shaped / Type 28 Identified by saucer shape.
Easier to use than raised-hub discs
Designed to be held at shallow angles

22. Changing the Discs UNPLUG IT!!!!!!!!!!!! Engage the spindle lock
Use the correct size wrench
Wear gloves and remove wheel
Snug new wheel with arbor wrench!

23. Can be a workout Using the portable disc grinder is hard work
Rest frequently to avoid fatigue

24. Fighting Fatigue – Handle Attachment
Reduces stress on hands and arms
Necessary for deep cuts
Makes it easier for disc change-over

25. Fighting Fatigue- Speed Lock
Locks the grinder into full speed
(Cruise-Control)
Convenient for heavy grinding
Several styles
All are located on the power switch

26. Safety Rules PPE: Eye protection, long sleeve leather gloves
face shield is recommended
Use correct wheel for the application
Check condition of wheel before each use
Replace once wheel is half gone
Do not remove the wheel guards
Secure your work piece
Shoot your sparks in a safe direction
LET THE GRINDER DO THE WORK
Never set it down on while the disc is spinning

27. Pneumatic Grinders Use compressed air instead of electricity
Better for extended grinding applications
Need a good air-compressor to keep up
Same attachments available as electric