Machinist Program: Drill Press Safety and Operations

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Questions and Answers

What is the primary purpose of dressing for safety in the drill press operation?

To enhance workpiece quality

To reduce machine maintenance

To prevent personal injuries (correct)

To improve machine performance

What is the formula to calculate RPM in the drill press operation?

RPM drive x Diameter of Drive Pulley = RPM of the driven ÷ Driven Pulley Diameter (correct)

RPM drive - Diameter of Drive Pulley = RPM of the driven + Driven Pulley Diameter

RPM drive + Diameter of Drive Pulley = RPM of the driven - Driven Pulley Diameter

RPM drive ÷ Diameter of Drive Pulley = RPM of the driven ÷ Driven Pulley Diameter

What is the recommended action when changing the drill bit?

Always stop the spindle with your hand

Use lubricants to cool the drill bit

Never leave the key in the drill chuck (correct)

Wear jewelry while operating the machine

What is the purpose of the sensitive drill press speed change mechanism?

To allow for smooth speed changes Signup and view all the answers

What is a critical safety consideration when using keyed chucks or drill drifts?

Attending to potential pinch points Signup and view all the answers

What is the average speed range of the drill press?

600 – 2800 RPM Signup and view all the answers

What is the purpose of the upright/column speed change mechanism?

To allow for alternate speed changes Signup and view all the answers

What is a common hazard associated with forcing the drill bit too much?

Workpiece damage Signup and view all the answers

What is the primary function of a drill press?

To remove material from a solid mass using a cutting tool. Signup and view all the answers

What type of chuck is commonly used in a sensitive drill press?

Keyed chuck Signup and view all the answers

What is the maximum hole diameter capacity of a sensitive drill press?

5/8 inch Signup and view all the answers

What is the purpose of reaming?

To produce an accurate sized, smoothly finished hole Signup and view all the answers

What is the purpose of countersinking?

To provide a square shoulder for the head of a bolt or cap screw Signup and view all the answers

What is the purpose of tapping?

To cut internal threads in a hole Signup and view all the answers

What is the purpose of spot-facing?

To smooth and square the surface around a hole Signup and view all the answers

What is the primary function of parallels on a drill press?

To elevate and support the work piece Signup and view all the answers

What is the range of speeds commonly found on a sensitive drill press?

300-3000 RPM Signup and view all the answers

What is the purpose of a drilling jig?

To guide the cutting tool Signup and view all the answers

What type of device is used to support long work pieces on a drill press table?

Supporting devices Signup and view all the answers

What is the key characteristic of a drilling jig?

It always has a guide for the cutting tool Signup and view all the answers

What type of clamp is used to hold and locate round objects on a drill press?

V-Block Signup and view all the answers

What is the purpose of clamps and straps on a drill press?

To secure very heavy and odd shaped work pieces Signup and view all the answers

Where should parallels be placed on a drill press?

Close to the drilling operation Signup and view all the answers

What type of device is used to secure heavy and odd shaped work pieces on a drill press?

Strap and clamp Signup and view all the answers

What is the formula to determine the RPM of the spindle?

RPM x Drive = RPM x Driven Signup and view all the answers

What is the unit of feed rate in drilling?

Distance per revolution Signup and view all the answers

What is the ideal chip shape in drilling?

Small and breaks free early Signup and view all the answers

What is the RPM calculation for manual machining in the metric system?

RPM = 320 x CS / Dia Signup and view all the answers

What is the dependency of feed rate in drilling?

On the type of tool, surface finish, power available, rigidity, strength, and material characteristics Signup and view all the answers

What is the consequence of high feed rates in drilling?

It increases the risk of collapsing thin wall tubing Signup and view all the answers

What is the purpose of the formula RPM x Drive = RPM x Driven?

To calculate the spindle RPM Signup and view all the answers

When drilling large holes, what is the purpose of drilling a pilot hole?

To reduce the pressure needed to feed the drill into the work Signup and view all the answers

What is the recommended size of the pilot hole compared to the size of the chisel edge of the larger drill?

Slightly larger than the chisel edge Signup and view all the answers

What is the consequence of drilling a pilot hole that is too large?

The hole will be out of round and have excessive chatter Signup and view all the answers

What is the purpose of using a transfer punch when drilling mating components?

To center punch the location on the mating part Signup and view all the answers

What is the recommended method for supporting the workpiece when drilling round work on the periphery?

Appropriately supporting the workpiece above the centerline of the part Signup and view all the answers

What is the purpose of aligning the center punch mark with a rule or vernier caliper?

To ensure the center line location is accurate Signup and view all the answers

What is the recommended diameter for drilling a pilot hole when the diameter is over?

¾ inch Signup and view all the answers

What is the purpose of setting the drill bit into the center of the drilled hole and reversing the rotation direction?

To float the tool into the location Signup and view all the answers

Study Notes

Drill Press Safety

Dress safely for operations
No jewelry, ensure eye safety, and hand safety
Remove chips carefully, use proper work holding, and avoid forcing the drill bit
Use lubricants, coolants, and be mindful of skin conditions
Never leave the key in the drill chuck or attempt to stop the spindle with your hand

Drill Press Speed Change

Average speed: 600-2800 RPM
Sensitive drill press speed change: RPM drive x diameter of drive pulley = RPM of the driven x driven pulley diameter
Example: 1800 x 4" diameter = 2400 RPM x 3" diameter

Column Type and Upright/Column Speed Change

Set speed when machine is not running
Variable RPM selector: RPM is set as machine is rotating
Damage will occur if this is not followed

Drill Press Operations

Drill press operation: drilling holes by turning a drill bit and plunging it downward into a work piece
Drill press applications: machine reaming, hole sawing, machine tapping, boring operations, spot facing, counter boring, and counter sinking

Drill Press Types and Applications

Sensitive drill press: capacity up to 5/8" hole diameter, keyed chuck, and speeds up to 3000 RPM
Work piece capacity: distance from the column to the center of the drill point
Table types: solid, rotation on the X axis, round tables rotate around the Z axis
Clamps and straps: secure heavy and odd-shaped work pieces

Supporting Devices

Parallels: elevate and support work pieces for drilling operations
Clamping technique: ensure parallels are close to the drilling operation to prevent work piece bending
V-blocks: hold and locate round objects on the drill press and milling machine
Angle plates and clamps: support long work pieces onto the drill press table

RPM Calculations

RPM calculation formula: RPM drive x diameter of drive pulley = RPM of the driven x driven pulley diameter
Example: 1800 x 4" diameter = 2400 RPM x 3" diameter
RPM calculation for the metric system: RPM = 1000 x CS / Dia for CNC and RPM = 320 x CS / Dia for manual machining
Spindle RPM adjustment: RPM x drive = RPM x driven

Feed Rate for Drilling

Feed rate is the velocity at which the cutter is fed or advanced against the work piece
Feed rate is dependent on: type of tool, surface finish desired, power available, rigidity of the machine and tooling setup, strength of the workpiece, and characteristics of the material being cut
Drilling feed rates: see table 3

Drilling Process

Set drill bit into the center drilled hole and reverse the rotation direction
Float the tool into the location, clamp the work piece, and verify alignment
Use permanent layout as a reference point for accurate hole locations

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Description

This quiz covers the safety guidelines and operational procedures for working with a drill press, including dress code, jewelry restrictions, and how to handle the machine safely. It also touches on speed change and other essential topics.