Denford Novamill 1996 Conversion, Hints & Tips Appreciated

[m_c]

BOBs come in various forms.
At the most basic, they connect to a parallel port and simply breakout the pins to more convenient terminals, which gives you the option of running Mach3/4 or LinuxCNC.

More advanced ones add in extra features, such as relays, 0-10V output (you'll need this for your spindle speed control), opto-isolation (avoids the computer getting fried if something goes wrong with the wiring).


However, you'll need to consider what controller and/or software you're going to use. Parallel port (PP) is the most basic option, but PPs are gradually dying. So then you're looking at external motion controllers. Common options being USB/Ethernet SmoothStepper, CSLabs CSMxxx, Dynomotion KFlop, PMDX (highly recommended for BOBs) have recently started producing their own controllers, and there are a few others. All those will tie you into certain software, so you might want to consider what software you'd like to run, as the software may be an additional cost depending on what you choose.
Then if you go the LinuxCNC option, you're looking at either PP, or internal Mesa cards.

I won't deny it, as for a beginner, it is a minefield!
In a nutshell, the more common options are-
LinuxCNC obviously runs on Linux. Only limitation is what you're capable of coding. Good if you like Linux or are willing to learn. Support can be very hit or miss.
Mach 3 will run indefinitely in Demo mode, with a limit of 500 lines of G-code and no Run From Here option.
Mach 4 will run with no limitations for a random amount of time before stopping generating motion.
Community support for Mach3 is excellent, as it's been around for a long time. Mach 4 isn't quite as good, but the user base is increasing as it becomes a more mature product.
There are also lots of proprietary controller and software packages, like PlanetCNC (and plenty others but just had a total mind blank!)

I personally run KFlops, as I like how highly customisable they are, and I've just changed from Mach3 to KMotionCNC (Dynomotion's own CNC software which is free) on my lathe, and I'm loving the no nonsense interface compared with Mach3. I'm still running Mach3 on my little probing machine, as KMotionCNC doesn't handle writing probing data to files, so there are pros and cons with all options.
However if I was starting as a beginner now, I'm not sure what option I would take!