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I converted a manual KBC GRIP-1340 lathe to CNC, kept the handwheels connected via encoders. I can manually machine or NC with it, It is more like a 'teaching' lathe, or tool room cnc lathe. Gives you the ability to quickly face or turn a diameter without having to write code or install a gui/cam thing to do it for you.

When i spin the handwheels, then stop, the machine stops. Encoder over-run is something you can disable. Sure you dont get feedback like a manual crank, but for the odd time doing something it doesnt matter. I put microswitches in the feed sticks and spindle fwd/rev lever, right now im using on screen dials to set the pitches and speeds, but its very similar to a manual lathe when you want it to be, and exactly a CNC lathe when it has to be.

I ended up using a 7i76E and 360ppr encoders connected with a small timing belt to 3d printed gears secured to the hand wheels inside an apron box i made from some rectangle tubing. My X ballscrew isnt in the apron it is beside the cross slide. I still have the cross slide on the lathe incase a quick taper job is required. Ill probably end up ditching it eventually for a more solid mount as its a weak point.

Anyways, the machine has made its money back and then a small fountain of cash to fund the other toys. It might not be everyones cup of tea, but it works very well.
 

I started with a parallel port for a lathe conversion, it was robust enough to do the job, but eventually went with a 7i76E for it, then a VMC i retrofit with 7i76E+7i84S, then now im doing another mill with a 7i95T, the Mesa hardware is fantastic- so good that china is now knocking it off!

Parallel port to start, then work your way through things. Lots of help here on this forum!!

If you have access to a PC with a parallel port, it's a cheap and easy way to get started in CNC using knockoff breakout boards from Amazon and some cheap stepper/driver kits. That's what I did. However, this is not a robust solution. I had many problems with port pins getting fried, for example. Getting any one of the Mesa cards (I used the 7i76E) is a bit more of an investment but the electronics are much more robust, and you get to enter the worlds of "industrial lego". At that point, you'd need LinuxCNC anyway, so might as well start there.

Also, it looks like GRBL is designed to run on an embedded board, not a PC, so if you want the lowest cost-of-entry, go LinuxCNC.

This is actually pretty easy, the 7i76e comes with 2 mpg inputs and you can have them on the 7i96 as well but you have to give up a couple of pins or a Stepgen.I can't quite remember what. If you ask PCW nicely, I'm sure he will sort out the correct solution.

Once you have that sorted, there is a good example of a MPG using parallel port pins in the docs. linuxcnc.org/docs/stable/html/examples/mpg.html

But in your case, you can ditch the axis select knob because you will use a dedicated MPG for each axis. Just implement the scale select knob... I have not thought about it but you may be able to use the one scale select for both MPGs. Using digital knobs lets you minimize the number of pins you need for the scale hence the mux4 components.

The Pi4b was marginal, sometimes requiring a slower servo thread but one guy I know says the Pi5 is flawless on real machines
I'd probably pair it with a mesa ethernet card. A Mesa 7i76eU has 5 axes, 16 outputs and 32 inputs but is extensible beyond that.
Linuxcnc supports 9 axes and 32 motors
Arduino is not useful for linuxcnc
There are several GUIs that support lathes but its always best to start with axis until you get everything functional.
Of course we are friendly!
You can mess with everything!
Check the docs as they list the GUI's available but you can write your own. Some support portrait mode.
I checked the other day, there's is over 1800 pages of docs but I always refer to the online docs.
There are no limits to motor size and it will control Ethercat and analog servo motors not just step and direction.
Linuxcnc is far more flexible than Centroid and is complete as opposed to Centroid where additional upgrades are required.
But it may require more effort from you  because there are probably more decisions you need to make becsause of LinuxCNC's flexibility

Re Youtube not sure on Lathe specific videos but I have a channel which is trying to produce tutorial type material.
This one is designed to be a general introduction describing the various pathways through Linuxcnc 

I'm currently working through a series of videos building a control panel from scratch using a parallel port (3rd one to be released tonight) with a couple more planned. Once fully functional, my plan was to replace the parallel port with other controller options. Sounds like I need to include a lathe walkthrough too!



 

mesaus has one:

mesaus.com/product/7i76eu/

 and our EU dealers have more

We should have the next build lot done in about 4 weeks

Thank you I will give that a look
 

There is one on ebay right now for $200.
www.ebay.com/itm/227441166265

   I have a new build project coming up and I need a 7i76EU for the build. But as my luck
usually runs Mesa Electronics is sold out of them. Does anyone know when more 
are expected to be in stock?

There is also a good MPG example in the docs except in Mesa land, you don't use the encoder component
linuxcnc.org/docs/stable/html/examples/mpg.html
Not sure on the 7i97 but there are some dedicated MPG pins on the Mesa 7i76e (and for the 7i96 if you use the right bit file and give up some pins.

I should note that I have a HP EliteDesk 800 G1 that could never run Ethernet cards reliably
 for more than an hour or so UNTIL I upgraded the kernel to 7.x

It also requires:

disabling irq coalescing
isolcpus=3
and pinning the Ethernet IRQ to CPU 3

With these changes, I never get dropped packets even after months of uptime
with a PC used for compiling, youtube etc etc

So does that mean you are in business and have a PC for spare parts? Hope so!
If not, I might be able to work in another site visit but it would cost you some footage for a YouTube video... 
There is an email that gets me on my @MrRodW YouTube channel

I connected a second PC to test wether the PC or the mesa board is dropping the connection. The result is the second PC works well for well over 20 minutes without interruptions or errors. it seems as the disconnected link was caused by the original PC. 

Just completed a successful installation of LinuxCNC version 2.9.8 on a Pi 4 with 4 gig of RAM.

Thanks to forum user "NWE" for recommending the version to download, named below:
2026-01-21-raspios-lcnc-2.9.8-trixie-arm64.zip

After downloading and using balenaEtcher to flash a 256Gig micro SD card, it booted to a Debian 13 Trixie style desktop and opened a "boot wizard".  After creating an account, the wizard recommended loading updates.  There was trouble after that, the login dialog box wouldn't accept any userids/passwords.

After rebooting and choosing NOT to load s/w updates, everything worked fine.  

I'm using LinuxCNC to retrofit a 1990's vintage Intelitek ProLight 3000 CNC lathe.  The original lathe was controlled using proprietary h/w and PC-based s/w.  I acquired a Mesa 7i76EU board as recommended by Mesa Technical Support so the journey is underway.

I see that LinuxCNC has a Mesa board config tool so I'll use that.

Any advice or coaching for me as an absolute LinuxCNC newbie is much appreciated.

 

Rykagon wrote:

Hello All,

- which Linux distro to load on the Pi 4.

 

Sounds like a fun project. 
Download the SD card  image at this page .
That should be a good start Pi4 + Mesa 7i76EU + TB6600. I've played a bit with the Pi, never used it in a retrofit, but I read people doing it regularly on this forum.