🚧 Under construction — VoTechWorks is being built. A free tech program — complimentary, as our commitment to get America working.
voTechWorksGrade 13 · a vocational technology learning center, by urbanicity
newSchoolWorks.com › VoTechWorks › Manufacturing & Marine › CNC Machining › CNC Setup: Machine Preparation, Tooling, and First-Part Verification › Lesson 12
MFG-CNC14-06 · Lesson 12 · 18 clock hours · lab

Integrated CNC Setup Practical: Cold Machine to Verified First Part

Objective. Working from a setup package and part drawing issued at the start of the session, students independently complete every step from LOTO and machine inspection through workholding setup, tooling, offset entry, prove-out, cutting, and FAI, producing a conforming first part within the allotted time.

⚠ Pending professional review

This lesson, its worked examples and its practice questions has not yet been verified by a licensed engineer or certified journey-level tradesperson or by a certification or approval body. It is a study draft and may contain errors. Do not use it as instructions for work on a job site or on live equipment. Always follow your instructor, your supervising professional, and current official references and regulations.

VoTechWorks program approval and accreditation are still in progress. Credentials are issued only by the certifying bodies named in each program, after their own exams.

What This Lab Demands

This session is the capstone practical for the CNC Setup course. You receive a sealed setup package and a part drawing at the start of the session. From that moment, you work independently — no coaching — to take a cold machine from a locked-out, powered-down state to a verified, conforming first part. Every credential you are working toward (NIMS Machining L1–2, Haas Certification, Mastercam Associate) expects exactly this kind of end-to-end competence.

The session is graded on a pass/fail basis. Any single out-of-tolerance feature or any LOTO error requires a full repeat of the practical. Read the entire setup package and drawing before you touch anything.

Step 1 — Plan Before You Touch

Open the setup package and read it completely. Identify the workholding device, all required tools and their positions, work coordinate system (WCS) origin location, all tolerances, and the inspection checkpoints listed on the FAI form. Sketch your sequence on scratch paper. Operators who plan first make fewer errors and finish faster. Confirm that the raw stock dimensions match the drawing.

Step 2 — LOTO and Pre-Shift Inspection

Lockout/Tagout (LOTO) is mandatory before any work inside the machine envelope. Follow the procedure posted on the machine:

1. Notify any affected personnel.

2. Identify every energy source (electrical, pneumatic, hydraulic).

3. Shut down the machine using the normal stop sequence.

4. Isolate each energy source at its control point (disconnect switch, valve).

5. Apply your personal lock and tag — your lock, your key.

6. Release or restrain stored energy (bleed air lines, allow spindle to coast fully to rest).

7. Verify zero energy: press the cycle-start button and attempt to jog the axis — nothing should move.

Now perform the pre-shift inspection: check coolant level, lubrication reservoir, chip load, way covers, and spindle for visible damage. Record findings on the inspection sheet in your setup package. Do not skip or abbreviate this record — it is part of your submitted documentation.

Required PPE for all machine work: safety glasses with side shields (ANSI Z87.1), steel-toed footwear, and close-fitting clothing with no loose cuffs or drawstrings. Gloves are not worn while operating rotating machinery; use a brush or hook to clear chips.

The instructor reviews your LOTO execution and inspection log and signs the LOTO release before you restore power.

Step 3 — Workholding and Indicating the Vise

Mount and torque the vise or chuck according to the setup sheet. Indicate the fixed jaw with a dial test indicator: acceptable runout depends on your part tolerances, but a general target for precision work is 0.0005 in. or better over the jaw length. Record your actual reading. A vise that is not square introduces location error that no offset can fully correct.

Step 4 — Tooling and Offset Entry

Install each tool in the holder specified by the setup sheet. Use the correct collet size and torque the retention knob or nut properly — an improperly seated tool can be pulled out under cutting loads. Preset each tool with the tool-length offset method your setup sheet specifies (touch-off to a reference surface, or tool-setting arm/probe if the machine is equipped). Enter geometry offsets into the offset table carefully; transpose errors are the most common cause of crashes during prove-out. Double-check every value after entry.

Enter the work offset (G54 or as specified). Set the WCS origin exactly as shown on the drawing — typically a corner of the stock or a datum feature. Document the offset values on your setup sheet.

Step 5 — Program Load and Dry-Run Prove-Out

Load the provided NC program from the USB drive or network location specified. Read through the program at the control: confirm tool numbers match your loaded tools, feed rates and spindle speeds are within machine limits, and coolant commands are correct.

Dry-run procedure:

Step 6 — Cutting and In-Process Measurement

Restore overrides to 100%, remove any air-cut offset additions, and run the program. At each checkpoint marked on the FAI form, stop and measure the designated feature. Use the correct gage: micrometer for turned OD/ID dimensions, bore gage for bores, thread gage for threaded features, caliper for less-critical lengths. Compare your measurement to the drawing tolerance. If a feature is trending toward the edge of its tolerance band, apply a wear offset correction before the finish pass — do not wait until the part is out of tolerance.

Step 7 — First Article Inspection (FAI)

After the program completes, deburr the part safely (deburring tool or file — not bare fingers on sharp edges). Measure every print-specified feature in the order listed on the FAI form. Record the nominal, tolerance, and your actual measured value for each feature. Sign and date the form. Package the part, the FAI form, the inspection log, the signed dry-run log, and the complete setup package, and submit everything to the instructor together.

The instructor re-measures selected features. If all features are within tolerance and documentation is complete and accurate, the practical is passed.

Key terms9

LOTO (Lockout/Tagout)An energy-control procedure that isolates all hazardous energy sources on a machine and applies a personal lock and tag to prevent unexpected startup before work inside the machine envelope is complete.
Setup PackageA complete document set issued to the operator that includes the part drawing, setup sheet, tool list, workholding instructions, offset starting values, and inspection checkpoint requirements for a specific job.
Work Coordinate System (WCS) / Work OffsetA programmable coordinate reference point (such as G54) that tells the CNC control where the program's zero origin is located relative to the machine's home position.
Tool-Length Offset (TLO)A value stored in the control's offset table that compensates for the measured length of each tool so the programmed Z-depth produces the correct depth on the part.
Dry-Run Prove-OutA pre-cut verification step in which the program is run with tools traversing in air (or at reduced feed with an artificially raised Z offset) to confirm the tool path is correct before any metal is cut.
Wear OffsetA small incremental value added to a geometry offset in the control to compensate for tool wear, allowing a machinist to bring a drifting dimension back into tolerance without editing the NC program.
First Article Inspection (FAI)A formal, documented measurement of every print-specified feature on the first production part to verify that the setup produces parts that conform to the drawing before full production proceeds.
Single Block ModeA CNC control mode in which the machine executes one program block at a time and then stops, giving the operator the ability to review each move before it happens — essential during prove-out.
Dial Test IndicatorA precision measuring instrument with a contact point that deflects a needle or digital readout to display small deviations in surface position; used to align a vise or fixture parallel to a machine axis.

Worked examples4

1. Your bore gage reads 1.2483 in. on a feature whose drawing calls for 1.2500 in. ± 0.0010 in. The finish bore pass has not yet been run. The current bore geometry offset is +0.0000 in. How much wear offset correction should you enter, and in which direction?
  1. Determine the nominal and tolerance limits: low limit = 1.2490 in., high limit = 1.2510 in.
  2. Current measured diameter: 1.2483 in. This is 0.0007 in. below the low limit — the bore is undersize (too small).
  3. To increase the bore diameter, the tool must move outward (away from center) by half the required diameter change because a bore diameter is affected by radial tool movement, but offset entry is in diameter terms on most Haas lathes and in radius terms on mills. Confirm which the control uses.
  4. On a Haas lathe with diameter-mode offsets: required diameter increase = 1.2500 − 1.2483 = 0.0017 in. Add +0.0017 to the wear offset for that tool to hit nominal, or add +0.0010 to move to the center of the tolerance band (1.2490 + 0.0010 = 1.2500 in.). Adding +0.0017 targets nominal and leaves equal tolerance in both directions.
  5. Enter +0.0017 in the wear offset column for the boring tool and re-run the finish pass.
Answer: Enter +0.0017 in. in the wear offset for the boring tool (diameter mode). The finish bore will then be 1.2500 in., which is at nominal and within the ±0.0010 in. tolerance band.
2. During dry-run prove-out you added +2.0000 in. to the Z geometry offset of Tool 1 to keep it in air. Before cutting, you must restore it. The original Z geometry offset was −7.3450 in. What value do you enter to restore the original offset?
  1. Dry-run offset = original + air-cut addition = −7.3450 + 2.0000 = −5.3450 in. This is currently stored in the control.
  2. To restore: new entry = dry-run value − air-cut addition = −5.3450 − 2.0000 = −7.3450 in.
  3. Alternatively, simply re-enter the original value directly: −7.3450 in.
  4. Verify by comparing the entered value to the setup sheet record before running the program.
Answer: Enter −7.3450 in. in the Z geometry offset for Tool 1 to restore the original tool-length compensation before cutting.
3. Your setup sheet specifies that the vise fixed jaw must indicate within 0.0005 in. over its 6.00 in. length. Your dial test indicator shows a total reading of 0.0008 in. over that span. How much out-of-tolerance is the vise, and what is the angular error in degrees (to the nearest 0.001°)?
  1. Total indicator reading (TIR): 0.0008 in. Required: ≤ 0.0005 in. Amount out of tolerance = 0.0008 − 0.0005 = 0.0003 in. excess deviation.
  2. Angular error: tan(θ) = opposite / adjacent = 0.0008 in. / 6.00 in. = 0.0001333.
  3. θ = arctan(0.0001333) ≈ 0.00764° ≈ 0.008°.
  4. The vise must be re-indicated and adjusted until TIR is 0.0005 in. or less before proceeding.
Answer: The vise is 0.0003 in. beyond the allowed deviation. The angular error is approximately 0.008°. Adjust and re-indicate before proceeding.
4. The FAI form lists a slot width as 0.7500 in. +0.000/−0.002 in. You measure 0.7494 in. Is the part in tolerance? Show your check.
  1. Determine tolerance limits: upper limit = 0.7500 + 0.000 = 0.7500 in.; lower limit = 0.7500 − 0.002 = 0.7498 in.
  2. Measured value: 0.7494 in.
  3. Check: 0.7494 < 0.7498 (lower limit). The measurement is 0.0004 in. below the lower limit.
  4. Conclusion: out of tolerance — the slot is too narrow by 0.0004 in.
Answer: The part fails. 0.7494 in. is 0.0004 in. below the lower limit of 0.7498 in. The feature is out of tolerance and the practical result for that feature is a fail.
In class: Each student receives a sealed setup package and part drawing; they plan their sequence, perform LOTO and pre-shift inspection, mount workholding, and indicate the vise — all before the instructor signs the LOTO release to proceed. · Students install and preset all required tools, enter all geometry and work offsets, load the provided NC program, and conduct a full dry-run prove-out with a signed dry-run checkpoint log before any metal is cut. · Students cut the part, perform in-process measurements at designated checkpoints, apply any necessary wear offset corrections, and complete the FAI form; they submit the part, all documentation, and the setup package to the instructor for final evaluation.
Materials: Haas CNC mill or lathe (assigned), all tooling and workholding required by the setup package, part drawing, setup sheet, FAI form, LOTO station, full gage kit (micrometers, calipers, bore gage, thread gages), raw stock
Check: All print-specified features within drawing tolerance confirmed by instructor measurement; LOTO executed without error; FAI form complete and accurate; full setup completed within the allotted session time — any single out-of-tolerance feature or LOTO violation is a fail requiring a full repeat practical.

Practice check8

Answer each question, then check it. Nothing is recorded; this is your own practice.

NIMS Safety and LOTO
1. During LOTO, after isolating all energy sources and applying your personal lock and tag, what is the correct next action before beginning work inside the machine envelope?
NIMS Measurement and Machine Setup
2. You are indicating a milling vise fixed jaw and the dial test indicator reads 0.0003 in. total over the jaw length. The setup sheet requires 0.0005 in. or better. What should you do?
Haas CNC Operation and Prove-Out
3. Which of the following is the correct purpose of a dry-run prove-out with an air-cut Z offset?
NIMS Offset Compensation and In-Process Measurement
4. A turned OD feature has a drawing tolerance of 1.6250 in. ± 0.0005 in. Your in-process measurement reads 1.6258 in. after the semi-finish pass. What corrective action is appropriate before the finish pass?
NIMS Measurement and Quality
5. Which gage is most appropriate for measuring the minor diameter of an internal thread to confirm it meets the drawing specification?
Haas CNC Offset Entry
6. On a Haas control, if you entered +2.0000 in. into the Z geometry offset of Tool 3 for dry-run air cutting, and the correct Z geometry offset from the setup sheet is −8.1200 in., which value must you restore before cutting?
NIMS Safety and FAI Standards
7. Which single failure automatically results in a required full repeat of the capstone practical in this program's grading policy?
NIMS Measurement and Blueprint Reading
8. A slot is dimensioned 0.6250 in. +0.001/−0.000 in. on the drawing. During FAI, you measure 0.6257 in. What is the correct FAI disposition?
Record this lesson on my transcript. Sign in with your key and enrollment email to record lessons (enroll free if you have no key). This page stays open to read and practise.
← Previous lessonProgram plan