Module 1: Assessment Quiz

Module: U8M1 - Machine Tool Fundamentals Duration: 20-30 minutes Passing Score: 70%

---

What is the primary function of a metal lathe?

To cut flat surfaces on metal stock

To drill holes in metal plates

To remove material from a rotating workpiece using a stationary cutting tool to produce cylindrical shapes

To bend metal into curved shapes

Submit

Explanation: A metal lathe rotates the workpiece while a stationary cutting tool is fed into it, removing material to produce cylindrical, conical, and faced surfaces. The workpiece rotates; the tool moves linearly.

What is the primary function of a milling machine?

To rotate the workpiece against a stationary tool

To remove material using a rotating multi-point cutter while the workpiece is held stationary or fed linearly

To heat-treat metal parts

To measure precision dimensions

Submit

Explanation: In milling, the cutting tool rotates while the workpiece is clamped to a table that moves in X, Y, and Z axes. This allows the creation of flat surfaces, slots, pockets, and complex 3D geometries.

What unit is commonly used to express cutting speed for metal machining operations?

RPM (revolutions per minute)

SFM (surface feet per minute) or m/min (meters per minute)

IPM (inches per minute)

Watts per hour

Submit

Explanation: Cutting speed (SFM or m/min) describes the linear speed at which the cutting edge moves relative to the workpiece surface. RPM is calculated from the cutting speed and workpiece/cutter diameter. Recommended SFM values are material-specific.

What is the formula to calculate RPM for a metal lathe operation?

RPM = SFM × Diameter

RPM = (SFM × 12) / (π × Diameter in inches), simplified to RPM = (SFM × 3.82) / Diameter

RPM = Diameter / SFM

RPM = SFM / 12

Submit

Explanation: The formula converts surface feet per minute to revolutions per minute based on the workpiece diameter. The constant 3.82 is derived from 12/π. For example, machining mild steel (100 SFM) at 1" diameter: RPM = (100 × 3.82) / 1 = 382 RPM.

What is "feed rate" in machining?

The speed at which the motor runs

The depth of each cut

The distance the cutting tool advances per revolution (lathe) or per tooth per revolution (mill)

The rate at which coolant flows

Submit

Explanation: Feed rate determines how much material the tool removes per revolution. On a lathe, it is expressed in inches per revolution (IPR). On a mill, it is expressed in inches per tooth (IPT) multiplied by the number of teeth and RPM to get inches per minute (IPM).

What is the purpose of cutting fluid (coolant) in metal machining?

To make the finished part shiny

To lubricate the chuck jaws

To cool the cutting zone, lubricate the chip-tool interface, flush chips, and extend tool life

To prevent rust on the machine

Submit

Explanation: Cutting fluid serves multiple functions: it removes heat from the cutting zone (preventing tool softening and workpiece distortion), lubricates the interface between the chip and tool face (reducing friction), and flushes chips away from the cut. Proper coolant use can increase tool life by 3-5x.

What material are most general-purpose lathe cutting tool inserts made from?

High-speed steel (HSS)

Cemented carbide (tungsten carbide)

Diamond

Cast iron

Submit

Explanation: Cemented carbide inserts (ISO grades like P, M, K designations) are the standard for modern machining. They maintain hardness at high temperatures (up to 1800°F), allow faster cutting speeds than HSS, and are available in indexable insert form for quick changes. HSS is still used for some operations and in smaller shops.

What does "depth of cut" refer to in metal machining?

How deep the drill bit penetrates

The total material removed from the workpiece

The radial distance the cutting tool penetrates into the workpiece surface in a single pass

The length of the cutting tool

Submit

Explanation: Depth of cut (DOC) is the amount of material removed per pass, measured radially from the original surface to the cut surface. On a lathe, a 0.050" depth of cut removes 0.050" from the radius, reducing the diameter by 0.100". Roughing passes use larger DOC; finishing passes use smaller DOC.

What are the three primary axes of movement on a milling machine?

A, B, C

Forward, backward, rotational

X (table left-right), Y (table in-out / saddle), Z (head up-down / quill)

Radial, axial, tangential

Submit

Explanation: The X-axis moves the table left and right, the Y-axis moves the saddle (and table) toward or away from the column, and the Z-axis moves the spindle head or quill up and down. These three axes allow the cutter to reach any point on the workpiece.

What safety device automatically disengages the lathe carriage feed at a preset position?

The emergency stop button

The chuck guard

The carriage stop (or automatic feed trip)

The tailstock lock

Submit

Explanation: The carriage stop is an adjustable mechanical device that automatically disengages the power feed when the carriage reaches a preset position. This prevents the tool from crashing into the chuck or tailstock and enables repeatable cut lengths.

What is the difference between climb milling and conventional milling?

Climb milling uses a larger cutter

In climb milling, the cutter rotates in the same direction as the feed; in conventional milling, the cutter rotates against the feed direction

Conventional milling is faster

There is no difference

Submit

Explanation: In conventional (up) milling, the cutter teeth engage the thinnest part of the chip first. In climb (down) milling, teeth engage the thickest part first. Climb milling produces a better surface finish and generates less heat but requires a machine with minimal backlash to prevent the cutter from pulling the workpiece.

What is the purpose of a lathe's compound rest?

To hold the chuck on the headstock

To support the tailstock

To provide angular tool positioning for taper turning, facing, and threading operations

To adjust spindle speed

Submit

Explanation: The compound rest sits on top of the cross slide and can be rotated to any angle. This allows the cutting tool to be fed at an angle to the workpiece axis—essential for cutting tapers, chamfers, and threading (where the compound is typically set to 29° or 29.5° for 60° thread forms).