Slide 001: Facing, Turning, and Shouldering Operations¶

Slide Visual¶

Facing, Turning, and Shouldering Operations

Slide Overview¶

This slide covers the three most fundamental lathe operations—facing, straight turning, and shoulder turning—including tool setup, parameter selection, and step-by-step procedures.

Instruction Notes¶

Facing¶

Facing produces a flat, smooth surface on the end of the workpiece perpendicular to the lathe axis.

Procedure: 1. Mount workpiece in chuck with minimal overhang (2× diameter maximum). 2. Mount a right-hand turning tool in the tool post, set to center height. 3. Set RPM based on the OD of the workpiece. 4. Position the tool just beyond the OD using the carriage. 5. Advance the cross slide to touch the face. Zero the cross slide dial. 6. Feed the tool across the face using the cross slide handwheel (outside to center or center to outside). Take light cuts: 0.010-0.020" per pass. 7. As the tool approaches the center, the effective SFM decreases. The surface finish at the very center may differ slightly.

Straight Turning (Cylindrical Turning)¶

Turning reduces the workpiece diameter to a specified dimension by feeding the tool along the axis.

Procedure: 1. Face the end, then take a light cleanup cut along the length (0.010" DOC) to establish a reference surface. 2. Measure the current diameter with a micrometer or calipers. 3. Calculate material to remove: (Current diameter - Target diameter) / 2 = total radial material. 4. Roughing passes: Set DOC to 0.050-0.100". Engage power feed at the selected IPR. Monitor chip formation. 5. Leave 0.010-0.020" for the finishing pass. 6. Finishing pass: Reduce DOC, increase speed, decrease feed rate for best surface finish. 7. Stop the lathe and measure. Adjust if needed.

Dial collar usage: On most lathes, each division on the cross slide collar = 0.001" of radius. Since you are cutting on one side, a 0.025" cross slide movement reduces the diameter by 0.050". Some lathes have direct-reading dials calibrated for diameter; check your machine.

Shoulder Turning¶

A shoulder is a step between two different diameters on the same workpiece.

Types: - Square shoulder: 90° step created by facing to a precise length, then turning the smaller diameter up to the shoulder - Filleted shoulder: Rounded transition for stress relief, created with a tool ground with a nose radius or by hand-blending - Angular shoulder: Chamfered transition, created with the compound rest set to the desired angle

Procedure for a square shoulder: 1. Mark the shoulder location with a parting tool groove or layout line. 2. Turn the smaller diameter up to within 0.050" of the shoulder mark. 3. Face the shoulder using the carriage handwheel for fine approach. 4. Blend the corner to the exact shoulder position.

Key Talking Points¶

Face the end first—it gives you a reference surface and cleans up saw marks
Always measure with the lathe stopped; never measure a rotating workpiece
Cross slide movement vs. diameter change: know whether your lathe reads radius or diameter
Power feed provides more consistent surface finish than hand feeding

Learning Objectives (Concept Check)¶

Can students perform facing to produce a flat, smooth surface?
Can students turn a workpiece to a specified diameter within ±0.002"?
Do students understand the relationship between cross slide movement and diameter change?

Last Updated: 2026-03-19