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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.
 

Thanks for enlightening us ignorant folks. I'll call Siemens and Heidenhain right away and tell them to remove that feature from DMT Kern, DMG, and the rest. I'm sure they'll be thrilled that someone has finally pointed out they've been doing it wrong ever since the 1980s.

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!!

The log file produced by the polygon pocketing program  produces g-code linear moves as its output.  If you stick a few m2 and percents and a few setup commands in that file and change its name to a .ngc file you can  mill simple things. 
(maybe)   (I'm assuming you have some other machine that you can run that program on)

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.

The 7I97T enable outputs should be able to drive that directly.

If you worry, you can always measure the current with a DVM
 

Aciera wrote:

@tuxcnc
So you like the old cranks, that's fine, but looking at your recent posts makes me wonder if you are maybe starting to turn into one:

It's just a stupid idea, even if someone does it and is happy with it...

You're wrong.

Nonsense.

It is big mistake.

One more little gray text on a gray background...
No, thank you.
 

I just hate political correctness.
If someone does something stupid, you need to inform them about it, not praise them and wait until they waste a lot of time and money.
And he will do whatever he wants anyway...

 

rines_design wrote:

The recommended Linux distribution for the latest version of LinuxCNC.
 

Download latest Debian iso image (current 13.6) and install. (There are thousands guides at the net.)
It is a good idea to manually partitioning and don't use swap partitions (Modern computers with at least few GB of RAM not need swap.)
LinuxCNC without CAD/CAM fits in 8 GB of disk space, 16 GB is better, more will be never used.
You should chose some lightweight window manager. (I preffered xfce4.)
LinuxCNC installation is simple, but I don't have the time or inclination to check now whether I made a mistake, but it should be like this:I don't remember the apt-get build-dep should be before or after ./debian/configure, the rest seems be properly.

@tuxcnc
So you like the old cranks, that's fine, but looking at your recent posts makes me wonder if you are maybe starting to turn into one:

It's just a stupid idea, even if someone does it and is happy with it...

You're wrong.

Nonsense.

It is big mistake.

One more little gray text on a gray background...
No, thank you.

Yes. This is actually one of the hard copies I currently have. Mainly looking for additional details for the other components, especially the control board for these machines.

timo wrote:

It might even be a thing to do a "virtual taper attachment" when moving the encoder driving z and x at the same time.
 

Just because something can be done doesn't mean it's worth doing or that it will work as expected.
MPG is intended for positioning movements, not working movements.
There are many reasons why you should not use MPG for turning, but I will give you just one - you can turn the handle faster than the axis is moving, in other words, when you are done turning, the axis will continue to move until it reaches the commanded position.
MPG is not a mechanical crank rigidly connected to the tool and giving the operator a feedback signal.
It's just a stupid idea, even if someone does it and is happy with it...

Mesa smart-serial is open, all Mesa firmware is open.
But keeping the USB panel as USB is almost certainly easier and may be technically better.

rines_design wrote:

• The installation steps for a fresh system.

On a fresh system:
(more details here linuxcnc.org/docs/stable/html/getting-st...etting-linuxcnc.html)
Download this file: www.linuxcnc.org/iso/linuxcnc_2.9.10-amd64.hybrid.iso
Write the file to a USB stick (at least 4.1GB) using the instructions here:
linuxcnc.org/docs/stable/html/getting-st...to_a_bootable_device
Plug the USb drive into the PC, turn it on, go to the BIOS screen (often by pressing F2 during boot) to set the USB stick as the boot device, save and exit, then follow the on-screen instructions. 
 

On my lathe:
bodgesoc.blogspot.com/2016/08/holbrook08.html
I installed a 7i73 inside the apron to handle the limit switches, handwheels and a jog-rate select knob (which is also a switch that selects manual mode to enable jogging).

Your 7i96 has a smart-serial port, so you would connect a 7i73 to that.

It means simpler cabling in the cable chain, but you need to use suitable cat5 cable to handle the continuous flexing. (eg Igus chainflex / LAPP Etherline FD)

I don't see anything in the photo to exclude the possibility that you are in the UK (I look at mains sockets) so if you are, Rapid Electronics sell a lot of these expensive industrial cables by the metre. www.rapidonline.com/lapp-0028308-liyy-pe...e-8-x-0-25mm-63-6718

I mean I cannot prove 100% right now, but I do not see it cannot be run with two hand encoders (at the same time)

It might even be a thing to do a "virtual taper attachment" when moving the encoder driving z and x at the same time.

I should get going...