The Working Machinist's Guide to
FANUC Macro Programming
Write custom macros that count parts, adjust offsets and run whole part families on the Oi.
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DRO
Quick Convert
Millimeter
× 25.4
Nearest 1/64
exact
F1
Geometry
F2
Machining
F3
Reference
CALC
Calculator
M
0
History
No calculations yet
DRL
Drill Chart
Closest drill—
Next larger—
Next smaller—
| Drill | Inch | mm | Type |
|---|
BOOKS
More from The Working Machinist
Enjoying the free Tool Box? The guides behind it go deeper on FANUC controls and shop documentation. Tap a cover to open it on Amazon.
ABOUT
About the Author
Tim Blakely
Tim Blakely has run FANUC-controlled CNC machines since 2009, working his way from operator to the programmer other machinists bring their hardest jobs to. He's self-taught in macros and parameters, and everything he writes comes off a real control on a real shop floor in North Carolina.
Visit workingmachinist.comBooks & Guides
Free from The Working Machinist. The Tool Box is the quick answer; the books are the full story. Tap a button, or scan a QR code with your phone, to open the book on Amazon.
The Working Machinist's Guide to
FANUC Parameters
Fix alarms, recover lost home position and build your own M-codes on the Oi.
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The Working Machinist's Guide to
FANUC Macros & Parameters
Both guides in one book for CNC operators: Macro Programming and Parameters. The best value in the series.
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The Working Machinist's
Setup & Operation Logbook
CNC Mill Edition. 90 setup sheets with work offsets, tool lists and first-article records, so the next run starts faster.
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Scan with your phone
ABOUT
About the Author
Tim Blakely
Tim Blakely has run FANUC-controlled CNC machines since 2009, working his way from operator to the programmer other machinists bring their hardest jobs to. He's self-taught in macros and parameters, and everything he writes comes off a real control on a real shop floor in North Carolina.
Visit workingmachinist.comCNC Angle
Setup
Long / short side — enter either, the other solves automatically
Enter values above
Worked examples — 24 in long side
| Example | Angle | Long side | Short side |
|---|
Formula:
short = long − (width × tan(90° − angle))Saw Angle
Given lengths
Stock width
in
width of tube / bar being cut
Cut Angle
Enter long and short side above
—
Triangle & Trig Solver
Right triangle — enter any two values, the rest solve automatically (angle C is always 90°)
Bolt Hole Calculator
Bolt circle setup
0° = 3 o'clock. 90° = 12 o'clock.
Angle Between Holes
—
°
Hole coordinates (from center)
| Hole | Angle | X | Y |
|---|
Formula:
X = r × cos(angle), Y = r × sin(angle)Paste-ready program output
Check before you cut. Generated code is a starting point only. TWM and Tim Blakely are not liable for its use. Simulate and verify every program before running it.
Feeds & Speeds
Tool & material
Optional — depth & width of cut (for material removal rate)
Spindle Speed
—
RPM
Feed Rate
—
Material Removal Rate
—
Enter depth and width of cut above to calculate.
Material reference — general carbide starting points
| Material | SFM | Chip load/tooth |
|---|
Starting points only — adjust for tool coating, machine rigidity, and actual diameter. Verify against tooling vendor data.
Drill & Tap
Thread
Tap type & thread engagement
Tap Drill Diameter
Enter thread values above
—
Reference — cut (75%) vs form (65%) tap drill
| Thread | Cut tap | Form tap |
|---|
Theoretical diameters — round to the nearest available drill. Form tap values are a general starting point; verify against your tap manufacturer's chart.
Hole Making Generator
Finished hole requirements
Required surface finish
Rough ≈ Ra 125-250 (as-drilled). Standard ≈ Ra 63-125. Fine ≈ Ra 16-32 (reamed/bored).
Recommended Process
—
Drill Size — Inch
—
Drill Size — Metric
—
Finishing operation
How this decision is made
Drill to size — general shop capability holds roughly ±0.003–0.005" with a Rough or Standard finish. If your tolerance and finish both fit that, a standard drill at (or near) final size is enough.
Drill + Ream — reaming typically holds ±0.0005–0.001" with a Ra 32-63 finish, and needs a pilot hole that leaves 0.01–0.03" of stock for the reamer to remove cleanly.
Drill + Bore — for tolerances tighter than about ±0.0005", boring is recommended, also needing a pilot hole leaving 0.01–0.03" of stock for the boring bar.
Mill to size — if no standard drill (inch or metric) lands within that 0.01–0.03" window below the finished size, there's no good pilot hole for a reamer or boring bar. Milling the hole to size (roughed with an end mill, finished by circular interpolation) sidesteps the problem entirely.
These are general shop guidelines, not a substitute for your own process capability data — adjust for material, hole depth-to-diameter ratio, and the tooling you actually have on hand.
Fanuc Thread Mill Code Generator
Thread
Thread mill & cut parameters — always inches, tool always outputs G20
Thread mill type
Program always applies G41 cutter compensation with this D offset.
Thread location
Hand
Milling
Spindle Speed
—
RPM
Feed Rate
—
Generated G-Code — verify & simulate before running
Check before you cut. Generated code is a starting point only. TWM and Tim Blakely are not liable for its use. Simulate and verify every program before running it.
General-purpose helical thread-milling template. Always verify tool path direction, work offset, tool length offset, and spindle direction, and simulate/backplot before running. Single-start threads only.
G-Code / M-Code Reference
Click any code for a full explanation — codes marked with a diagram icon also show a simple visual.
Unit Converter
Convert — inches ↔ millimeters
↔
Feet - Inches - Fraction → Decimal
/
Decimal Inches
—
in
Fraction / decimal / mm chart — 1/64″ to 1″
| Fraction | Decimal (in) | Millimeters |
|---|
GD&T Symbol Reference
Chamfer & Countersink
Tool
0 for a spot drill or pointed countersink. Chamfer mills often have a small flat.
What are you cutting?
Optional. Used for the chamfer width.
Tool Tip Z Depth
—
in
Chamfer Width
—
in
82° flat head socket cap screws — click a row to fill in the countersink
| Screw | Head dia. (sharp) | Close clearance |
|---|
Head diameters are the theoretical sharp maximum. Clicking a row sets 82° and the head diameter, so the head sits flush. Add .005–.010" to sink it below the surface. Check against your print. Formula:
Z = (D − tip) ÷ 2 ÷ tan(angle ÷ 2)Fits & Tolerances (ISO)
Size & fit — hole-basis ISO 286
Hole
—
Shaft
—
Fit
—
All common fits at this size — click a row to select it
| Fit | Type | Hole | Shaft | Clearance |
|---|
ISO 286 hole-basis fits, sizes up to 500 mm (19.68"). Positive clearance means a gap; negative means interference. Inch sizes are converted to mm to look up the tolerance, then converted back.
Print Check
1 · Title block — which tolerance applies?
Saved title blocks stay on this computer.
2 · The dimension on the print
Type it with the same decimal places as the print.
Use the print's own units. Fill in the optional boxes only when the dimension has its own tolerance, like +.002 / −.000.
High limit
—
Aim (middle)
—
Low limit
—
3 · Check a measured part (optional)
—
Enter a measured size to check it.
4 · True position
Feature
Modifier
True position Ø
—
Allowed Ø
—
—
True position
Ø = 2 × √(ΔX² + ΔY²). At MMC, bonus = how far the actual size has moved from MMC (hole: actual − low limit; pin: high limit − actual). Allowed = position tolerance + bonus. Datums are assumed to be the X/Y zero your measurements came from.