Presentation on theme: "Pedestal Grinders and Other Off-Hand Grinders Session 6."— Presentation transcript:
Pedestal Grinders and Other Off-Hand Grinders Session 6
Shop Tools and Techniques2 Grinding Grinding is the process of removing material by the cutting action of individual hard and sharp abrasive grains or particles of a revolving wheel as they come in contact with the surface to be ground.
Shop Tools and Techniques3 Grinding Wheels Abrasive Particles that are held together by a glue-like material called the bond.
Shop Tools and Techniques4 Grinding Wheels Abrasives either Natural Occurring or Synthetic Natural Emery Corundum Flint Garnet Quartz Diamond
Shop Tools and Techniques6 Grinding Wheels Natural verses Synthetic Synthetic Has replaced most naturally occurring abrasives Superior Hardness Durability Controlled Grain size Controlled Purity Controlled Shape
Shop Tools and Techniques7 Grain Size Grain Size determines the coarseness or fineness of the grinding wheel Coarse WheelFine Wheel Ranges from 6 (very coarse) to 240 (very fine)
Shop Tools and Techniques8 Bond Types Vitrified Bond Most common (Clay or Feldspar) Resinoid Bond Synthetic resins Rubber Bond Flexible Bond Metal Bond Electrically conductive wheels
Shop Tools and Techniques9 Grinding Wheel Grade The degree of strength that a bond holds the abrasive grains in the bond setting. Grade A Softest Grade Z Hardest
Shop Tools and Techniques10 Grinding Wheel Grade The degree of strength that a bond holds the abrasive grains in the bond setting. Hardness of Material Hard Material – Soft Wheel Area of Contact Large Contact – Soft Wheel Speed of Wheel Higher Speed – Softer Wheel
Shop Tools and Techniques11 Grinding Wheel Grade The degree of strength that a bond holds the abrasive grains in the bond setting. Machine Condition Rigid Machine – Soft Wheel Rate of Feed High Rates – Hard Wheel Operator Characteristics Ram Rod – Hard Wheel
Shop Tools and Techniques12 Grinding Wheel Structure The structure of the grinding wheel is the space relationship of the grains and the bonding material to the voids that separate them. Structure 0 Small Spacing Structure 12 Larger Spacing
Shop Tools and Techniques13 Grinding Wheel Structure Grinding Wheels are fitted with paper blotters that act as cushions between the wheel and flanges holding them on.
Shop Tools and Techniques14 Grinding Wheel Features Abrasive Type Aluminum Oxide, Silicon Carbide, CBN, Diamond Grain Size 8 coarse to 240 very fine Grade A – Soft to Z – Hard Structure 0 – Close to 12 - Open
Shop Tools and Techniques15 Grinding Wheel Features Bond Type V – Vitrified S – Silicate B – Resinoid R – Rubber E – Shellac M – Metal Diameter Width Bushing Size Shape
Shop Tools and Techniques16 Grinding Wheel Manufacture The methods used in the manufacturing of specific grinding wheels are dependent upon the individual abrasive grain, the bond to be utilized and the particular application that the abrasive will be used for.
Shop Tools and Techniques17 Pedestal Grinder. The grinding wheels are mounted on a double-ended spindle and are held in place between two flanged disks Typically, a roughing or coarse grained wheel is usually mounted on one end of the spindle and a fine wheel on the other. A tool rest is provided for each wheel so that tools may be held or steadied while being ground
Shop Tools and Techniques33 Pedestal Grinder Accessories Spark guard and tool rest setting gage
Shop Tools and Techniques34 Pedestal Grinder Accessories Lockout lock and tag
Shop Tools and Techniques35 Pedestal Grinder Accessories Lockout hasps
Shop Tools and Techniques36 Dismounting A Wheel 1. Turn off grinder 2. Lock-out and Tag-out grinder 3. Disconnect exhaust collector 4. Loosen and relocate Eye shield 5. Loosen and relocate tool rest 6. Loosen and relocate spark guard
Shop Tools and Techniques37 Dismounting A Wheel 7. Remove wheel guard 8. Loosen wheel mounting nut Right hand threads on right side Left hand threads on left side 9. Remove Wheel 10. Inspect wheel for damage Discard damaged wheel
Shop Tools and Techniques47 Inspect Wheel For Damage
Shop Tools and Techniques48 Mounting a Wheel 1. Clean Spindle shaft 2. Replace inner washer 3. Ring test wheel to mount 4. Install wheel on spindle 5. Replace outer washer 6. Tighten wheel mounting nut 7. Rotate wheel manually and observe
Shop Tools and Techniques49 Mounting a Wheel 8. Replace wheel guard 9. Reconnect exhaust collector 10. Relocate and tighten tool rest 11. Relocate and tighten spark guard 12. Remove Tag and Lock 13. Stand to side and restart grinder 14. Dress wheel
Shop Tools and Techniques50 Clean Spindle Shaft