106 Lathe

On a lathe, what components are in motion and which parts are held rigidly? How does this compare to other common subtractive processes?

On a lathe, the workpiece rotates (held in the chuck or between centers) while the cutting tool is held rigidly in the tool post and moved linearly. This is the opposite of most other subtractive processes like milling, where the workpiece is held stationary and the cutting tool rotates.

What tool must you always verify is removed before turning on the lathe?

The chuck key. If left in the chuck, it will be ejected at high speed when the lathe is started, creating a serious projectile hazard.

Identify all buttons and knobs on the system and their function.

Power switch (main on/off); Forward/Reverse switch (controls spindle direction); Speed selector — Low/Medium/High (selects belt-driven gear range); Emergency stop (cuts power to the spindle only — does NOT cut electrical power to the machine); Carriage handwheel (moves carriage longitudinally); Cross-slide handwheel (moves tool toward/away from workpiece); Compound rest handwheel (moves tool along compound angle); Half-nut lever (engages carriage to lead screw for threading); Feed engagement lever (engages power feed); Tailstock handwheel (advances/retracts quill); Tailstock lock (locks tailstock to bed). NOTE: Verify against your specific machine.

Identify and demonstrate all functions for the critical components of the carriage.

The carriage holds and moves the cutting tool along the workpiece. Key components: the saddle (rides along the bed ways), the apron (contains controls for longitudinal/cross feed), the cross slide (moves tool perpendicular to the bed), the compound rest (adjustable angle slide for the tool post), and the tool post itself (holds the cutting insert).

Identify and demonstrate all functions for the critical components of the tailstock.

The tailstock sits on the opposite end of the bed from the headstock and can be slid and locked at any position. It holds centers (live or dead) to support long workpieces, or a drill chuck for drilling operations along the axis. The tailstock quill is advanced with the handwheel and locked with the quill lock.

Explain all terms found in the Glossary of Terms in the Grizzly Lathe Manual.

NOTE: This answer is specific to your Grizzly manual's glossary. Review the glossary section of your manual and add definitions here.

What are the safety hazards of overly long stock on a lathe?

Overly long unsupported stock can flex and whip at speed (bar whip), creating a severe struck-by hazard to the operator and anyone nearby. It also causes vibration, poor surface finish, and tool chatter. Long stock must be supported with a tailstock center or steady rest.

What are the differences between a 3 Jaw Chuck and a 4 Jaw Chuck?

A 3-jaw chuck is self-centering — all three jaws move simultaneously, making it fast to use for round or hexagonal stock. A 4-jaw chuck has independently adjustable jaws, allowing it to hold irregular shapes and be dialed in for very precise centering, but it requires more setup time and skill.

What additional component can be added to stabilize long stock?

A steady rest or a follow rest. The steady rest mounts to the bed ways and stays fixed. The follow rest mounts to the saddle and travels with the carriage — it must be readjusted after every cut as the workpiece diameter changes.

What are the three fundamental machine areas that present the most risk of hazard and injury?

The chuck, the workpiece/part, and the lead screw. These are the primary entanglement, ejection, and struck-by hazard zones on the lathe.

What hazards are presented by tools left on and near the machine?

Tools left on the machine (e.g., a chuck key left in the chuck) can become dangerous projectiles when the machine starts. All tools must be returned to the cart when not in use — never leave them on or near the machine.

What are the different types of stabilizers used in the tailstock and how do they differ?

A dead center is a fixed, non-rotating point — the workpiece spins against it and requires lubrication. A live center has a bearing and rotates with the workpiece, reducing friction and heat. Live centers are preferred for most operations; dead centers are used when very high precision is needed.

What hazards are presented by chip build up on a lathe and how can this be mitigated?

Chips are razor-sharp and cause lacerations. Built-up chips can interfere with the workpiece and damage the cutting tool. Use a chip brush to clear chips regularly — never use bare hands or compressed air, which can drive chips into eyes or the machine's ways.

What must be worn when operating a lathe?

Safety glasses or a face shield. Close-fitting clothing with no loose sleeves. Closed-toe shoes. Hair must be tied back. No gloves — gloves can catch on the rotating workpiece and pull the hand in.

What must be removed from your person before operating a lathe?

All jewelry (rings, watches, bracelets, necklaces). Loose or baggy clothing. Gloves. Long hair must be tied back or covered.

How is surface cutting speed determined on a lathe?

Look up the recommended surface footage (SFM) for your material in the machinist's handbook. Then calculate RPM using the formula: RPM = (4 × SFM) / D, where D is the workpiece diameter in inches. The 4 is an approximation of 12/π.

How much travel does each tick mark on the hand wheels indicate?

Cross-slide: 1 thou (0.001") per graduation. Compound rest: 1 thou (0.001") per graduation. Carriage handwheel: 5 thou (0.005") per graduation. Tailstock handwheel: 1 thou (0.001") per graduation. NOTE: Verify against your specific Grizzly model.

What tools are used to remove chips from the machine?

A chip brush. Never use bare hands, rags while the machine is running, or compressed air. Compressed air can drive chips into eyes and into the machine's ways.

Gib

A tapered wedge located along a sliding member to take up wear or to ensure a proper fit.

Turret

A machine fixture that holds multiple tools and can be revolved and indexed to position