Part 4

Overview of a 1st Year Machinist Apprentice

• A machinist apprentice is a tradesperson who learns to operate and maintain machinery and equipment in a manufacturing setting.
• The 1st year of apprenticeship focuses on building foundational skills and knowledge in machining and manufacturing.

Key Skills and Knowledge

• Machine operation:
  • Familiarity with manual milling machines, lathes, and drill presses.
  • Understanding of machine safety and proper operation procedures.
• Tooling and measurement:
  • Knowledge of cutting tools, including types, uses, and maintenance.
  • Understanding of measurement instruments, such as calipers and micrometers.
• Material properties:
  • Familiarity with common materials, including metals, plastics, and composites.
  • Understanding of material properties, such as strength, hardness, and corrosion resistance.
• Manufacturing processes:
  • Introduction to machining processes, including turning, milling, and drilling.
  • Understanding of manufacturing terminology and concepts.

Work Environment and Safety

• Workshop safety:
  • Familiarity with workshop hazards, such as moving machinery and falling objects.
  • Understanding of personal protective equipment (PPE) and safety procedures.
• Workshop organization:
  • Knowledge of workshop layout and organization principles.
  • Understanding of tool storage and maintenance procedures.

Apprenticeship Structure and Expectations

• Apprenticeship duration: Typically 4 years, with 1st year focused on foundational skills and knowledge.
• Training and assessment:
  • Combination of on-the-job training and classroom instruction.
  • Regular assessments and evaluations to track progress and identify areas for improvement.
• Workplace expectations:
  • Apprentices are expected to work safely and efficiently, following established procedures and protocols.
  • Active participation in learning and skill development is essential.

Overview of a 1st Year Machinist Apprentice

• A 1st year machinist apprentice learns to operate and maintain machinery and equipment in a manufacturing setting.

Key Skills and Knowledge

• Machine operation involves familiarity with manual milling machines, lathes, and drill presses, as well as understanding machine safety and proper operation procedures.
• Tooling and measurement knowledge includes understanding cutting tools, their types, uses, and maintenance, and measurement instruments like calipers and micrometers.
• Material properties include familiarity with common materials like metals, plastics, and composites, and understanding material properties like strength, hardness, and corrosion resistance.
• Manufacturing processes include introduction to machining processes like turning, milling, and drilling, and understanding manufacturing terminology and concepts.

Work Environment and Safety

• Workshop safety involves familiarity with workshop hazards like moving machinery and falling objects, and understanding personal protective equipment (PPE) and safety procedures.
• Workshop organization involves knowledge of workshop layout and organization principles, and understanding tool storage and maintenance procedures.

Apprenticeship Structure and Expectations

• The apprenticeship typically lasts 4 years, with the 1st year focused on foundational skills and knowledge.
• The training and assessment process combines on-the-job training and classroom instruction, with regular assessments and evaluations to track progress and identify areas for improvement.
• Workplace expectations include working safely and efficiently, following established procedures and protocols, and active participation in learning and skill development.

Safety and Measurement

• A softener in lifting and hoisting procedures using a sling is a device used to protect the sling from shape edges of the load.
• The lead of a screw thread is the axial distance a nut advances on a screw thread after one complete turn.
• When a fiber rope is hitched, the strength of the rope is reduced by 25 percent.
• A hacksaw pitch blade is used for cutting material with a small cross section, such as high carbon steel drill rod, and the pitch of the blade depends on the material being cut.

WHMIS (Workplace Hazardous Materials Information System)

• WHMIS is designed to provide safety for products called "controlled products".
• A worker's responsibility when dealing with WHMIS is to ensure that appropriate control measures are in place to protect workers.
• The employer must provide a material safety data sheet for each controlled product used in the shop.
• A precautionary statement in WHMIS is a phrase that describes direct measures to alert the worker about the level of hazard.

Machine Tools

• A CNC (Computer Numerical Control) machine is a type of machine tool that uses a computer program to control the machine's movements.
• A CNC machine can be programmed to perform a variety of tasks, such as cutting, drilling, and milling.
• The advantages of CNC machines include increased accuracy, speed, and efficiency, as well as reduced labor costs.

CNC Turning Machines

• A CNC turning machine is a type of CNC machine that is used for turning, facing, and cutting operations.
• The purpose of centre drilling on a CNC turning machine is to provide a 60-degree conical surface for a bearing centre.
• The program speed when reaming on a CNC turning machine is generally 25 to 50% of that used for drilling.
• A self-driving centre on a CNC turning machine is used when the entire length of the workpiece must be machined in one pass.

CNC Machine Components

• A transducer is a device that monitors external variables and converts them into signals for a machine control unit.
• A soft limit switch on a CNC machine is a type of virtual or programmed switch that resides in the computer program.
• A microset adjustable centre on a CNC machine is used to adjust the centre of the workpiece.
• A facing tool on a CNC machine is used to cut a flat surface at right angles to the axis of the workpiece.

CNC Programming

• The surface speed formula used with CNC turning machines calculates the cutting speed based on the diameter of the workpiece.
• A CNC program can be used to control the machine's movements, including the spindle speed and feed rate.
• The M code M30 in a CNC program causes the machine to stop executing a program.

Machine Operations

• A taper attachment on a lathe is used to cut tapers and eliminates all backlash.
• A floating reamer holder may decrease the effect of reamer misalignment.
• An oil mist lubrication system ensures that the oil is always clean and is not affected by oil viscosity.

Machine Control

• The MCU (Machine Control Unit) of a CNC machine is the nerve centre of the machine, coordinating all machine operations.
• The servo drive control in a CNC machine develops appropriate signals from program data for driving servo motors.
• Machine zero on a CNC machine is the absolute reference point and origin of the machine coordinate system.

CNC Turning Centers

• A sliding headstock turning center is a type of CNC turning center that is also called the Swiss style turning center.
• A twin spindle vertical turning center is a type of CNC turning center that has two spindles.
• A gang style horizontal spindle turning center is a type of CNC turning center that has multiple spindles.

Drilling and Cutting

• The RPM for drilling a hole depends on the material being drilled and the type of drill being used.
• A hacksaw pitch blade is used for cutting material with a small cross section, such as high carbon steel drill rod.
• A band saw blade is used for cutting curved shapes and has a specific pitch and number of teeth.

Grinders and Lathe Operations

• A grinder is used to grind and polish materials.

• The flange of a grinder should be one-third the diameter of the wheel.

• Backlash on a lathe refers to the space between meshing gears.### Machining Operations

• Machining that produces a channel on the diameter of a workpiece is known as grooving.

• Machining to separate a part from the main bar stock is known as parting.

Lathe Specifications

• The size of a lathe is determined by the largest diameter of workpiece that can be supported over the ways and the greatest length of workpiece that can be supported between centers.
• The headstock is always attached to the left side of the bed.

Lathe Components

• A stop shaft is clamped to the ways to stop the movement of the carriage.
• A turret stop is clamped to the ways to stop the movement of the carriage.
• A lathe dog engages a slot in the drive plate, with different types including safety clamp, straight tail, standard bent tail, and clamp.
• A blotter is a heavy piece of metal attached to each side of a grinding wheel.

Machining Techniques

• Profiling is machining of curved surfaces.
• The feed rate for a roughing cut should be as high as the cutting tool and the machine can handle.
• The feed rod moves the carriage at a slower rate than the lead screw does for threading.

CNC Turning Centres

• Twin spindle-twin turret arrangements are used in high production machining, allowing work to be machined on both ends.
• Single spindle-single turret arrangements are the most common arrangement and are used in high production machining.

Work Holding Devices

• A vise is a very versatile and convenient work holding device.
• A tapered pin is used to secure a drill chuck to its shank and has a 3 1/2 inch taper per foot.

Trade Mathematics

• 1 pound = 0.454 kg and 1 inch = 25.4 mm are common conversions.
• The amount of taper is expressed as taper per foot in the imperial system.
• Angles can be calculated using trigonometric functions.

Print Reading

• A circle drawn in an isometric projection would form an ellipse.
• Material section lines on a blueprint represent different materials, such as steel, rubber, and others.
• A set square is used to draw angles, with common angles including 90°, 45°, 45° and 45°, 60°, 30°.

Fasteners and Surface Finishes

• A bolt designation includes the diameter, threads per inch, and thread form, such as 3/8 - 16 UNC X4.
• A machine screw driving recess can be a slotted spanner, hex castle, self-locking, acorn, or hex flange.
• Surface roughness is the average deviation from the centerline measured in microinches or micrometers.
• Waviness refers to the distance between repeated wavy patterns on a surface finish.

Machinist Practice Test

• The test consists of 120 questions covering various topics in machinist trade.
• The test can be printed and answered offline, and the answer key can be printed separately.

Safety and Measurement

• A narrow rule is a type of rule that has graduations only along one edge.
• The PASS acronym outlines the proper use of a portable extinguisher: Point the nozzle, Aim the hose, Spray, Sweep the fire.
• The pitch of a 3/8 - 16 UNC screw thread is 0.0625 inches.
• The WHMIS pictogram represents a health hazard.

Machining Operations

• A crosscut sawmill file is a triangular shaped single cut file used for sharpening mill saws with M-shaped teeth.
• DNC stands for Direct Numeric Control.
• The maximum angle for a template using a hydraulic tracer attachment on a lathe is 15 degrees.
• The Z-axis on a CNC lathe represents the movement of the carriage.

Lubrication Systems

• A lubrication system can be classified into different types, including enclosed circulating, drip feed, ring oiler, and splash lubrication.
• The enclosed circulating lubrication system relies on a pump to force oil under pressure into a bearing.

CNC Machines

• A single spindle-double turret on independent slides allows for different diameters to be machined at the same time.
• A Chucking Centre machine is designed for work that is held in a chuck at one end and supported with a tailstock at the other.
• The MCU of a CNC machine is the nerve centre that coordinates all machine operations.

Tooling and Workholding

• A solid dead centre is used when the entire length of the workpiece must be machined in one pass.
• A floating reamer holder can decrease the effect of reamer misalignment.
• A telescoping taper attachment uses two binding screws to set the depth of cut.

Drilling and Tapping

• The feed rate for a roughing cut should be as high as the cutting tool and the machine can handle.
• The calculated RPM for drilling a 32 mm hole in leaded steel using a carbide drill is 1492.09.

Tolerancing and Dimensioning

• Full format suppression is used to reduce the number of zeros in the full format dimensions.
• Geometric dimensioning and tolerancing is used to fully define form and control angular relationships.

Blueprint Drawings

• The abbreviation TYP on a blueprint drawing stands for Typical.
• Anti-friction bearings are not normally dimensioned on a blueprint drawing.
• The acronym TPF on a blueprint drawing stands for Taper Per Foot.
• A ratio of 1:1 is drawn at actual size on a blueprint drawing.

Machining Operations

• Machining that produces a channel on the diameter of the workpiece is known as turning.
• Machining to separate a part from the main bar stock is known as parting off.

CNC Machines

• DNC refers to Direct Numeric Control.
• The Z axis in a CNC lathe represents the movement of the carriage.
• A single spindle-double turret on independent slides in a CNC machine allows for different diameters to be machined at the same time.

Grinding Wheels

• Grinding wheels are classified according to abrasive type, size, and bonding material.

Lubrication Systems

• The enclosed circulating lubrication system relies on a pump to force oil under pressure into a bearing.

Drill Point Angles

• The drill point angle for general-purpose use is 118 degrees.

Chucking Centre Machines

• A chucking centre machine is designed for work that is held in a chuck at one end and supported with a tailstock at the other.

Forming Tools

• A forming tool is used to cut intricate cylindrical profiles.

MCU (Machine Control Unit)

• The MCU is the nerve centre of the CNC machine, coordinating all machine operations.

Solid Dead Centres

• A solid dead centre is held in the tailstock spindle and does not turn.

Lubrication Advantages

• The advantage of using grease over oil as a lubricant is that it tends to adhere better to the surface of the part.

CNC Turning Centers

• A CNC turning centre without a turret to hold cutting tools is a vertical single turning centre.

Drilling Machines

• A radial drill machine is best suited for drilling in very large workpieces that are difficult to position.

Workpiece Alignment

• Running a dial indicator along a workpiece is a good way to align the workpiece when the carriage is between the headstock and the steady rest.

Saddle Movement

• The saddle movement is at an angle of 90 degrees to the axis of the machining spindle.

Programming Zero

• When using the back face as program zero, all X and Z coordinate values are positive.

RPM Calculation

• The calculated RPM for drilling a 45 mm hole in Aluminium using a carbide drill is 2012.9.

Transducers

• A resolver is a type of positional transducer.

Band Files

• A band file consists of a series of short files riveted to a steel band.

Angle Denotation

• An angle denoted with polar coordinates when measured counter-clockwise is positive.

Lathe Dogs

• A safety clamp is a type of lathe dog that engages a slot in the drive plate.

Tapers

• The large diameter of a taper, where TR=1:60, d=42mm, TL=120mm, is 45 mm.

Decimal Equivalents

• The fraction 3/2 expressed in decimal form is 1.5.

Triangle Angles

• An angle of 550 and 450 in a triangle makes angle 50.7 degrees.

Unit Conversions

• 91.44 cm is equivalent to 3 feet.

Triangle Perimeter

• The perimeter of a parallelogram with sides 38 inches, 3 feet, and 18 inches is 12.33 feet.

Trigonometry

• COS 45 degrees is equal to 0.707.

Measuring Tapers

• The most accurate method of measuring a taper is using a taper micrometer.

Print Reading

• A scale of 1:10 on a drawing indicates that the actual diameter of a gear is 10 times the scaled diameter.

Surface Finishes

• Surface roughness refers to the average deviation from the centerline measured in microinches or micrometers.

Key Types

• A square key is used between the hub and a 6-inch diameter shaft.

Fits

• A FN3 fit is used for ordinary steel parts or light shrink fits on thin sections.

Machine Tools

• A solid hand reamer should leave 0.002 inches of material before hand reaming.
• In a CNC program, a G-code prepares the machine for what is coming.

Lubrication Systems

• A flow-through system allows lubricant to escape into the environment after use.

CNC Machining

• The calculated RPM for drilling a 0.585-inch hole in 3.5 diameter brass using an HSS twist drill is 979.43.
• Carbide is a cutting material that retains its hardness to a very high temperature and is also known as Stellite.
• In CNC turning centers, "parting-off" refers to machining the outside diameter of the workpiece.
• The term "resolution" refers to the smallest slide movement the machine can control and act upon.

Safety Interlocks

• If a machine's safety interlock is disabled, do not use the machine.

Cutting Speeds

• The recommended cutting speed SFPM for high-speed steel drills when the workpiece material is Aluminium is 300.

Work Holding Devices

• The oldest and simplest work holding device is the lathe centre.

CNC Programs

• In a CNC program, an M-code M08 activates the spindle in the forward direction.
• In a CNC program, an M-code M08 does not stop the machine from executing a program.

Axis Identification

• When using the right-hand rule for identifying an axis, the thumb represents the X-axis.

CNC Machines

• Full format suppression is used to reduce the number of zeros in full format dimensions.
• In a CNC machine, the diameter used for spindle calculations for threading operations is the major diameter of the thread being cut.

Turning Applications

• Chucking work involves working on a short slug.
• When the work overhang is more than 4 times its diameter, tailstock support for a CNC turning machine is important.

PLCs

• A PLC (Programmable Logic Controller) connects RAM directly to binary logic, allowing machining logic.

Measurement

• COS 45 degrees is equal to 0.707.
• The most accurate method of measuring a taper is using a taper micrometer.

Print Reading

• On a drawing with a scale of 1:10, a scaled diameter of 21 mm corresponds to an actual diameter of 210 mm.
• Surface roughness refers to the average deviation from the centerline measured in microinches or micrometers.