310101bB Layout & Power Tools

Objective:
- Describe and apply safe techniques for using various workshop hand tools and power tools.

Initial Steps:
- Coat the metal work piece with layout dye for a clean dark surface.
Tools Used:
- Scribers: Used to scratch the metal workpiece with a straightedge or square.
- Dividers:
  - Firm joint and spring joint types used to scribe arcs and circles.
  - Sizes range from 6” to 12.”
- Hermaphrodite Calipers: Used to scribe lines parallel to an edge.
- Squares (Solid and Combination):
  - Used to scribe perpendicular lines and 90° angles.

Sensitive Drill Press:
- Used for small precise work with up to a ½" diameter hole.
- Cutting pressure determined by the operator.
- The spindle is driven by a V-belt, with adjustable belt speed by moving belts to different sheaves.

Procedure:
- Mark the material with a center punch.
- Clamp the workpiece securely.
- Start the drill bit in reverse to center it in the punch hole.
- Safety Note:
  - Do not hold the workpiece with hands; always clamp it.
- Drill a pilot hole to prevent chattering of the main drill bit.

Specifications:
- Used for drilling small holes up to 12.5mm / ½".
- Limited feed pressure; rotation speed not adequate for small bits.
- A 1/8" bit requires 3200 rpm (400-3000 rpm for variable drills).
- Safety Warning:
  - Freehand drilling is dangerous; large bits can twist or throw away from hands.
- It’s advisable to drill larger holes using multiple smaller bits in stages.

Types:
- Available in fractional, number, letter, and metric sizes.
- Shanks are straight or tapered with two helical flutes for chip removal and cooling.
- Cutting Mechanics:
  - Cutting occurs at the drill point.

Definition:
- Rate at which the outside edge of the drill moves through material.
Importance:
- Incorrect speeds can generate excessive heat leading to wear and damage.

Peripheral Speed:
- Fastest part of the drill is the outside edge.
Feed Rates:
- Measures of drill feed into the work: inches per revolution or millimeters per revolution.

Safety Considerations:
- Common workplace tools; special attention required to prevent injury.
- Key Features:
  - Ensure grinding guards are in place, and eye shields are properly adjusted.
  - Adjust tool rests to 1/16" to 1/8" (1.6mm to 3.2mm) from grinding wheel.
  - Use three layers of eye protection; cracked wheels can explode.

Safety Gear:
- Avoid loose-fitting clothing; tie long hair back.
- Use a face shield and wear gloves only when necessary.

Best Practices:
- Use the entire face of the grinder to prevent uneven wear.
- Avoid grinding aluminum; ensure wheel pores are unclogged.
- Dress the wheel if it becomes glazed or uneven.

Key Features:
- 90° angle grinders with a reversible handle and disc shield for operator protection.
- Maintain knowledge of the RPM of rotating accessories for safety.

Operating Speed Information:
- Maximum operating speed for bench and pedestal Alundum grinding wheel is 4970 RPM.
Types of Grinding Wheels:
- Wire wheel, coarse wheel, buffing wheel, diamond wheel, cutting wheel.

Precautions:
- Always wear goggles, face shield, and hearing protection.
- Ensure no loose clothing, and that discs are tight and crack-free.
- Stand to the side until reaching top speed, support your work, and utilize tool rests.

Usage:
- Designed for square and miter cutting.
Safety Features:
- Check cutting discs for chips and nicks.
- Ensure spark guard is in place and wear appropriate personal protective equipment (PPE).