See every pass before the chuck spins.
NC Proof Turn reads your Haas ST or Fanuc 0i-TF program the way the control does, cuts it on a 3D bar — roughing, finishing, grooving, threading, live tools — and points to the line that would crash, scrap the part or alarm the machine.
Built for how a lathe really cuts.
Turning programs move fast and close to the chuck. NC Proof Turn follows every move, every cycle and every macro, and tells you what is wrong and why it matters.
Reads it like the control
Haas NGC and Fanuc 0i-TF dialects: one-line or two-line G71/G76, decimal-point rules, modal words carried from line to line.
3D cutting, setups & measuring
Watch the bar being cut, flip it for the next setup, and measure diameters and lengths on the finished part. Tool nose radius comp (G41/G42) included.
Roughing & finishing cycles
G71/G72 Type I and II, G73 and G70 expanded into the real passes, with checks on the P/Q profile blocks and profile direction.
Threads, grooves & holes
G76 and G92 threading, G74/G75 peck grooving and drilling, and drilling cycles at the centre line.
Chuck & jaw collisions
Flags a tool that runs into the jaws or the chuck face, for every setup in the program.
Rapids into the part
Every G00 that would plunge into material is flagged with how deep it goes — the classic lathe crash.
Live tools & C axis
M133/M134/M135, the C axis and G112 polar interpolation — and a warning when a live tool cuts without turning.
Macro B & subprograms
#variables, IF/GOTO/WHILE, G65 calls, M97/M98/M99 and #3000 alarms run as on the machine.
Spindle & coolant sense
G96 at X0 without a sensible G50 limit, cutting with the spindle stopped, or a tool cutting with the coolant off.
Your machine, your control.
Checks follow the real control's rules, so a program that passes in NC Proof Turn reads the same way on the machine.
- Haas ST-series lathesNGC control, including live tooling and C axis
- Fanuc 0i-TF lathesTwo-line G71/G72/G76 syntax and Fanuc decimal-point rules
- Inch and metricG20 / G21, diameter programming on X
- Runs in your browserWindows, Mac or iPad · installs as an app · works offline · your programs stay on your computer
It doesn't just say "error". It shows you where.
When NC Proof Turn spots a risky move, it highlights the block, explains what would happen, and shows it on the part. Fix it, re-run, and move on.
1O1001 (SHAFT OP1) 2G21 G18 G40 G99 3T0101 (OD ROUGH) 4G50 S2500 5G96 S180 M03 6G00 X52.0 Z2.0 7G71 U1.5 R0.5 8G71 P10 Q20 U0.4 W0.1 F0.25 9... 14G00 X30.0 Z-40.0 ⚠ G00 rapid runs into the part15G01 X52.0 F0.2 16M30
From program to proven in three steps.
Open your program
Open the .nc file from CAM or paste the code. NC Proof reads the stock and tools from the header comments, or you enter them.
Watch it cut
The bar is cut in 3D at real machine speed. Slow it down, step block by block, or jump to any line.
Fix and send
Every message points to its line and says what is wrong and why. Edit in place, re-run, and save the proven .nc file.
Questions machinists ask.
Which lathes and controls does NC Proof Turn support?
Haas ST-series lathes with the NGC control and Fanuc 0i-TF lathes, in inch or metric. Programs for other Fanuc-style lathe controls usually run too, but the checks follow Haas and Fanuc 0i-TF behaviour.
Do I need to install anything?
No. NC Proof runs in a modern web browser on Windows, Mac or iPad. You can also install it as an app, and it keeps working offline.
Is my G-code uploaded anywhere?
No. Your programs are read and simulated on your own computer; they are not sent to our servers.
Does it handle live tooling and the C axis?
Yes: M133/M134/M135, C-axis moves and G112 polar interpolation are simulated, and NC Proof warns when a live tool cuts without turning.
Can I edit the program in NC Proof?
Yes. Edit any line in place, the toolpath redraws as you type, and you can save the result as an .nc file for the machine.
Ready to prove your next lathe job?
Open NC Proof Turn and run your program on a virtual part first.
Working on a mill instead? See NC Proof Mill →