Practice
How Long Does It Take to Learn G-Code? A Realistic Timeline
Recognizing the core 20 to 30 G-codes takes two to four weeks of daily practice. Reading full programs takes two to three months. Writing them takes longer.
Lawrence Arya··10 min
Practice
CNC Basics for an Apprentice Mechanical Fitter
Moving from fitting into CNC? You already have the measurement and drawing skills. The new part is G-code. Here are the basics a mechanical fitter needs first.
Lawrence Arya··4 min
Code reference
I, J, K vs R in G02: Arc Center Words Explained
I, J, and K give the arc center as an offset from the start point, while R gives the radius. Here is when each works, and why full circles need I and J.
Lawrence Arya··5 min
Guides
Do You Have to Type Leading Zeros in G00? (G0 vs G00)
No. G0 and G00 are the same, and leading zeros are optional everywhere. The thing that actually matters is the decimal point, not the leading zero. Here is why.
Lawrence Arya··4 min
Practice
G-Code Basics in 10 Minutes: A Free Beginner Guide
Learn the G-code essentials fast: what a program is, the dozen codes that cover most of it, and a tiny example. Then practice them so they actually stick.
Lawrence Arya··4 min
Code reference
G-Code vs M-Code: What Is the Difference?
G-codes control how the machine moves and M-codes control machine actions like the spindle and coolant. Here is the real difference and how they work together.
Lawrence Arya··4 min
Code reference
G17, G18, G19: Plane Selection in G-Code Explained
G17 selects the XY plane, G18 the XZ plane, and G19 the YZ plane. Here is what plane selection controls, why arcs depend on it, and when to switch.
Lawrence Arya··4 min
Code reference
G20 vs G21: Inch vs Metric in G-Code, Explained
G20 tells the control to read the program in inches and G21 in millimeters. Here is the difference, why the wrong one is dangerous, and how to keep them straight.
Lawrence Arya··4 min
Code reference
G28 Return to Home Position in G-Code, Explained
G28 sends the machine back to its reference (home) position, through an intermediate point you specify. Here is how it works and how to use it safely.
Lawrence Arya··4 min
Code reference
G41 vs G42: Cutter Compensation Left vs Right
G41 offsets the cutter to the left of the path and G42 to the right. Here is how cutter compensation works, the D register, and how to engage it without a crash.
Lawrence Arya··4 min
Code reference
G43 Tool Length Offset in G-Code, Explained
G43 applies a tool's stored length so its tip reaches the programmed Z, no matter how long the tool is. Here is how G43, the H register, and G49 work.
Lawrence Arya··5 min
Code reference
G54 Work Offsets Explained for CNC Beginners
G54 tells the machine where your part zero is. Here is what a work offset stores, how G54 to G59 differ, and how to set one without cutting in the wrong place.
Lawrence Arya··4 min
Code reference
G81 vs G83: Drilling Canned Cycles Explained
G81 is a simple drill cycle and G83 is a peck drill cycle for deep holes. Here is how canned cycles work, their R, Z, and Q words, and when to use each.
Lawrence Arya··5 min
Guides
How to Calculate Feed Rate for G01 (Beginner Guide)
The F value on a G01 line is feed rate, and you calculate it from spindle speed, feed per tooth, and the number of flutes. Here is the formula with a worked example.
Lawrence Arya··5 min
Code reference
How to Calculate I and J for a G02 Arc (Worked Examples)
I and J are the distance from the arc's start point to its center: I = center X minus start X, J = center Y minus start Y. Two worked examples and a self-check.
Lawrence Arya··5 min
Guides
How to Read a CNC Program for Beginners
A CNC program is read one block at a time, top to bottom. Here is how to decode each line of a real program, the letters that matter, and how to get fluent.
Lawrence Arya··5 min
Code reference
How to Remember Lathe M-Codes vs Mill M-Codes
The core M-codes are identical on lathes and mills, so learn them once. The real difference to remember is the tool change: M06 on a mill, the T word on a lathe.
Lawrence Arya··5 min
Practice
How to Stop Mixing Up X and Z on a Lathe (For Good)
Two anchors end the lathe axis confusion: Z is always the spindle axis on every machine, and X is the diameter. Here is why the mix-up happens and the fix.
Lawrence Arya··4 min
Code reference
Left-Hand Threading M-Code: M04 vs M03 Explained
A left-hand tap runs on M04, the reverse spindle code, with the G74 cycle on mills. For single-point threading, the spindle and feed direction together set the hand.
Lawrence Arya··5 min
Code reference
M06 Tool Change in G-Code, Explained for Beginners
M06 executes a tool change while the T word selects the tool. Here is how T6 M06 works, the safe sequence around it, and why G43 always follows.
Lawrence Arya··4 min
Guides
Why Did My End Mill Break on G01? Common Causes
An end mill usually breaks on a G01 feed move from overload: too much feed, too deep a cut, a straight plunge, or a wrong speed. Here are the causes and fixes.
Lawrence Arya··4 min
Code reference
Why Is G02 Cutting a Straight Line? Common Causes
G02 cuts a straight line when the arc is not actually defined: missing I and J words, a firmware without arc support, the wrong plane, or a huge radius.
Lawrence Arya··5 min
Code reference
Blank G-Code Test Worksheet: Make One That Actually Works
A blank G-code worksheet is a fine offline study aid if it forces recall. Here is what to put on one, and why a write-in format beats a plain code list.
Lawrence Arya··5 min
Practice
CNC Operator Jobs in Dubai: What the Test Questions Cover
CNC operator hiring tests in Dubai and the UAE focus on the same fundamentals everywhere: reading G-code, common codes, measurement, and safety basics. Here is how to prepare.
Lawrence Arya··5 min
Practice
CNC Practical Test Examples for a Job Interview (With Answers)
Sample CNC interview questions with answers: read this block, what does M03 do, G02 vs G03, and units. Practice these and the test feels familiar.
Lawrence Arya··5 min
Practice
CNC Practice With No Wi-Fi: How to Drill G-Code Offline
Shop floors and workshops often have no signal. Here is how to keep practicing CNC codes without Wi-Fi, and what to look for in an offline-friendly tool.
Lawrence Arya··5 min
Practice
G-Code Fill-in-the-Blank Quiz: Why This Format Sticks
A fill-in-the-blank quiz forces you to produce the answer, not pick it. For CNC codes that is the format that builds real recall. Here is how to use it.
Lawrence Arya··5 min
Practice
G-Code Flashcards You Can Download: Generic Decks vs CNC Drills
You can make or download G-code flashcards for offline study, but generic decks miss the CNC-specific mix-ups and timing. Here is how to get both.
Lawrence Arya··5 min
Practice
G-Code Test for a Job Interview: What to Study and How
What a G-code test in a CNC job interview usually covers, the codes to know cold, and a fast way to drill them before you walk in.
Lawrence Arya··5 min
Code reference
G90 vs G91: Absolute vs Incremental (and Why It Crashes Beginners)
G90 is absolute positioning and G91 is incremental. Mixing them up sends moves to the wrong place, which is a classic beginner crash. Here is the difference.
Lawrence Arya··5 min
Guides
How to Safely Test a G-Code Program: Beginner Concepts
The checks beginners learn before running a new program: dry run, single block, rapid override, and a graphics preview, explained at a concept level.
Lawrence Arya··5 min
Practice
Is There a Game to Learn G-Code?
There is no big 'G-code video game,' but game-style recall drills exist and work. Here is what is actually available and what to look for.
Lawrence Arya··5 min
Practice
The Most Basic G-Code Program Example, Explained Line by Line
A complete but minimal G-code program, explained one line at a time, so you can see how the common codes fit together. A teaching example, not a runnable file.
Lawrence Arya··5 min
Practice
No-Wi-Fi CNC Operator Cheat Sheet: What to Memorize First
A cheat sheet app is useless when the shop floor has no signal. Here is the short list an operator should know cold, plus how to keep it offline.
Lawrence Arya··5 min
Practice
Free Offline CNC Simulator vs a Practice App: Which Do You Need?
A CNC simulator models machine motion; a practice app drills the codes. If your goal is memorizing G-code, a simulator is the wrong tool. Here is the honest difference.
Lawrence Arya··5 min
Practice
Shop-Floor G-Code Reference vs Recall: Which Do You Need?
A reference app looks codes up; recall practice means you do not have to. Here is the difference, and why beginners are better served by drilling than by another lookup app.
Lawrence Arya··5 min
Guides
Why Did My CNC Crash on G00? Common Beginner Causes
A G00 rapid moves at full speed, so a wrong offset, tool length, or start point turns a small mistake into a crash. Here are the usual causes, explained for learners.
Lawrence Arya··5 min
Practice
Beginner CNC Code Practice: How to Actually Memorize G-Code
A practice-first plan for memorizing the G-code and M-code a CNC beginner needs, built around short daily recall instead of long manuals.
Lawrence Arya··5 min
Code reference
G00 vs G01: Rapid vs Linear Feed, Explained for Beginners
G00 is a rapid positioning move and G01 is a controlled linear feed move. Here is the difference, why beginners mix them up, and how to keep them straight.
Lawrence Arya··5 min
Code reference
G02 vs G03: Clockwise vs Counterclockwise Arcs Explained
G02 cuts a clockwise arc and G03 cuts a counterclockwise arc. Here is how to tell them apart, which way to look, and why beginners reverse them.
Lawrence Arya··5 min
Code reference
Common G-Codes Every CNC Beginner Should Know
A short reference list of the G-codes that show up in almost every CNC program, with a one-line meaning for each, built for beginners.
Lawrence Arya··5 min
Code reference
M03 vs M04 vs M05: Spindle Codes Made Simple
M03 starts the spindle clockwise, M04 starts it counterclockwise, and M05 stops it. Here is what each does and how to remember the set.
Lawrence Arya··5 min
Code reference
Common M-Codes Every CNC Beginner Should Know
A short reference of the M-codes you will meet first: spindle, coolant, tool change, and program control, each with a plain-language meaning.
Lawrence Arya··5 min
Practice
How to Memorize G-Code Faster: A Practice-First Method
Five techniques that make CNC G-code stick: retrieval practice, two-way recall, spacing, drilling mix-ups, and reviewing only your weak codes.
Lawrence Arya··5 min
Code reference
Modal vs Non-Modal G-Codes: What Beginners Get Wrong
Modal G-codes stay active until you change them; non-modal codes act only on their own line. Here is why that distinction trips up beginners.
Lawrence Arya··5 min