ITI Turner Interview Questions and Answers

Name the main parts of a lathe.

Bed, headstock (with spindle and chuck), tailstock, carriage (saddle, cross slide, compound rest, tool post, apron), lead screw and feed rod.

How to say it: Name them in order from left to right along the bed. It is easy to remember and sounds confident.

Which operations can be done on a lathe?

Facing, plain (straight) turning, step turning, taper turning, chamfering, grooving, parting off, drilling, boring, reaming, knurling and thread cutting.

What is the difference between a three-jaw and a four-jaw chuck?

A three-jaw chuck is self-centring (all jaws move together), and suits round and hexagonal work. A four-jaw chuck has independently moving jaws, so it holds square or irregular work and can be set for very accurate centring with a dial gauge.

How can you turn a taper on a lathe?

By swivelling the compound rest (short, steep tapers), by offsetting the tailstock (long, gentle tapers between centres), with a taper-turning attachment, or with a form tool for short tapers.

How do you cut a thread on a centre lathe?

Set the gearbox for the pitch, grind or select a tool to the thread angle (60° for metric) and set it square with a thread gauge, engage the half-nut and take light cuts, using the thread-chasing dial to pick up the same thread each pass. Check with a thread gauge or the mating part.

What is cutting speed, and how is spindle speed worked out?

Cutting speed is the speed of the work surface past the tool, in metres per minute. Spindle speed N = (1000 × cutting speed) ÷ (π × diameter in mm). Larger diameters need lower rpm for the same cutting speed.

How to say it: Write the formula: interviewers often ask you to work one out.

What is the difference between feed and depth of cut?

Feed is how far the tool moves along the work per revolution (mm/rev). Depth of cut is how deep the tool goes into the work in one pass. Roughing uses more depth and feed; finishing uses less.

What are the main angles on a single-point cutting tool?

Rake angles (top and side), clearance angles (front and side), and the cutting-edge angles. Rake helps the chip flow; clearance stops the tool rubbing on the work.

HSS or carbide, when do you use which?

HSS tools are tough and can be reground on a bench grinder, good for general work and threading. Carbide inserts hold their edge at much higher cutting speeds and are used in production and CNC.

Why is coolant used?

To cool the tool and the work, lubricate the cut, wash chips away and improve surface finish and tool life.

What is the least count of a micrometer and a vernier caliper?

Outside micrometer: 0.01 mm (0.5 mm pitch ÷ 50 thimble divisions). Common metric vernier caliper: 0.02 mm. Check zero error before measuring.

What do G00, G01, G02 and G03 mean in CNC?

G00 rapid positioning, G01 linear interpolation (straight cutting move at feed), G02 circular interpolation clockwise, G03 circular interpolation anticlockwise.

What are M03, M04, M05 and M30?

M03 spindle on clockwise, M04 spindle on anticlockwise, M05 spindle stop, M30 end of program and reset (on most controls).

What are work offset and tool offset?

The work offset tells the machine where the job's zero is; the tool offset stores each tool's length or position so the program cuts to size with every tool. Wrong offsets crash tools or scrap parts, so set and check them before the first cut.

What safety do you follow on a lathe?

Remove the chuck key before starting, wear goggles, no gloves, loose sleeves or chains near the rotating chuck, keep hair tied, never measure or clean chips by hand while the job is turning (use a brush or hook), and stop the machine before adjusting.

What is the usual practical test?

Turning a job to a drawing (facing, step and taper turning, a groove and often a thread) within the given tolerance, then measuring it. On a CNC test: setting offsets and running or editing a simple program.

How to say it: Check size after every pass near the final dimension; an undersize job cannot be saved.