Turn G-code: conversational lathe cycle generator for LinuxCNC (12 cycles)
03 Oct 2026 18:51 - 03 Oct 2026 19:21 #350083
by Odessit
Replied by Odessit on topic Turn G-code: conversational lathe cycle generator for LinuxCNC (12 cycles)
Update: Archimedean spiral - real cut on video
Here is the face spiral cycle cut on my lathe, start to finish (real cut, not an air run). Two frames are attached; a short video of the whole cut (49 s, sped up 2-4x, with music) is on the cycle page:
turngcode.com/en/features/archimedean-spiral/
I painted the face black before cutting so the spiral is easy to see on camera; the paint went on a bit unevenly, so some lands look thinner than they are. The video colour is slightly corrected for contrast, nothing else is edited.
Parameters: diameter 10 -> 110 mm, 3 starts, 2 mm insert (groove) + 2 mm land = 4 mm per turn, spiral lead 12 mm, 1 mm deep in 3 passes + 1 finishing pass, 50 RPM, right-hand.
How it works: the spiral is a G33 move along X, synchronized with the spindle encoder - the same way threads are cut, only across the face instead of along Z. The program works out the lead from the insert width, the land between turns and the number of starts.
Handy detail: the hand of the spiral is set simply by the order of the diameters. Start at the small diameter and finish at the large one - you get a right-hand spiral. Swap the start and end diameters (cut from the outside in) - and the same cycle gives a left-hand spiral, with the same spindle direction.
More on the geometry, lead and speeds, with a sample program:
turngcode.com/en/blog/archimedean-spiral-face-groove/
Questions and criticism welcome.
And here is the cycle form with exactly these parameters (English UI):
- Geometry: start and end diameter, pitch P (the land between turns), insert width, number of starts, depth, number of passes, finishing allowance and finishing passes, plunge feed.
- Spindle: roughing and finishing RPM.
- Approach / retract: safe X/Z and retract X/Z.
- Options: tool T number in the program, coolant M8, comments, M30 at the end, G7/G8 output.
The program works out the real pitch per turn (insert width + land = 4 mm) and the spiral lead (x 3 starts = 12 mm) by itself. The 2D preview on the right shows the planned G33 path and the current pass, so you can check the spiral before the machine moves. Generate writes the .ngc file, Send to LinuxCNC hands it over to LinuxCNC.
Here is the face spiral cycle cut on my lathe, start to finish (real cut, not an air run). Two frames are attached; a short video of the whole cut (49 s, sped up 2-4x, with music) is on the cycle page:
turngcode.com/en/features/archimedean-spiral/
I painted the face black before cutting so the spiral is easy to see on camera; the paint went on a bit unevenly, so some lands look thinner than they are. The video colour is slightly corrected for contrast, nothing else is edited.
Parameters: diameter 10 -> 110 mm, 3 starts, 2 mm insert (groove) + 2 mm land = 4 mm per turn, spiral lead 12 mm, 1 mm deep in 3 passes + 1 finishing pass, 50 RPM, right-hand.
How it works: the spiral is a G33 move along X, synchronized with the spindle encoder - the same way threads are cut, only across the face instead of along Z. The program works out the lead from the insert width, the land between turns and the number of starts.
Handy detail: the hand of the spiral is set simply by the order of the diameters. Start at the small diameter and finish at the large one - you get a right-hand spiral. Swap the start and end diameters (cut from the outside in) - and the same cycle gives a left-hand spiral, with the same spindle direction.
More on the geometry, lead and speeds, with a sample program:
turngcode.com/en/blog/archimedean-spiral-face-groove/
Questions and criticism welcome.
- Geometry: start and end diameter, pitch P (the land between turns), insert width, number of starts, depth, number of passes, finishing allowance and finishing passes, plunge feed.
- Spindle: roughing and finishing RPM.
- Approach / retract: safe X/Z and retract X/Z.
- Options: tool T number in the program, coolant M8, comments, M30 at the end, G7/G8 output.
The program works out the real pitch per turn (insert width + land = 4 mm) and the spiral lead (x 3 starts = 12 mm) by itself. The 2D preview on the right shows the planned G33 path and the current pass, so you can check the spiral before the machine moves. Generate writes the .ngc file, Send to LinuxCNC hands it over to LinuxCNC.
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06 Oct 2026 21:07 #350156
by tommylight
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First, thank you for making me feel a lot better about this, i checked your website, and the first thing you mention is the fact that LinuxCNC has such tools. Thank you for the respect.
Also checked the comparison, but i can not decide anything as i have very little experience with a CNC lathe, so i will leave that to others to decide for themselves.
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As for the website, see the attached picture, it is trying to run a script that points to a fuzzy website, see above the mouse.
This should be easy to remove, just check your HTML/CSS/JS files for that web name and remove it.
It also may be functional, but since everything works fine without it, you might as well remove it.
Again, thank you for being fair and respectful, very much appreciated.
Replied by tommylight on topic Turn G-code: conversational lathe cycle generator for LinuxCNC (12 cycles)
I did not say that, at least id did not want to say that, i meant i am sure about SheetCAM, but not about the rest, so if the rest have trial versions, it should also be possible to add yours, and i mentioned where the password should be, but last i checked the wiki was 15 years ago.Thanks Tom, fair points. Understood about the wiki - open source only, I'll leave it.
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First, thank you for making me feel a lot better about this, i checked your website, and the first thing you mention is the fact that LinuxCNC has such tools. Thank you for the respect.
Also checked the comparison, but i can not decide anything as i have very little experience with a CNC lathe, so i will leave that to others to decide for themselves.
-
As for the website, see the attached picture, it is trying to run a script that points to a fuzzy website, see above the mouse.
This should be easy to remove, just check your HTML/CSS/JS files for that web name and remove it.
It also may be functional, but since everything works fine without it, you might as well remove it.
Again, thank you for being fair and respectful, very much appreciated.
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