We need some more 2nd operation capacity and redundancy and we have an old Hardinge lathe gathering dust. It already has a nice spindle and 3-phase motor (I hope, as I have not yet put power to it). Would be nice if we had an unused machine with a 16C sized spindle as that would also handle many of our 1st op jobs too, but this little 5C setup will do many of our jobs.
As a side note: We also have another old 5 foot long lathe bed that is begging to become the base platform for a double-lathe setup - 16C spindle on the leftmost 35 inches of it, and a 5C spindle on the rightmost 25 inches of it. I'm even contemplating making it into a 75-degree slant-bed design. A LOT of capacity from a small footprint! This double-lathe project will wait until we find suitable spindles (or I get the ambition to make my own starting with more readily available drop-in spindle cartridges).
See attached renderings of my initial design ideas.
I'm thinking of the following major features:
- all aluminum (except for the rails, hardware, fasteners, etc)
- double T-slot for mounting a nice gang tooling holder
- plenty of extra T-slot space on servo end of X platform for cutoff and other tools.
- around 10 inches of X and Z travel
- steppers - size 34 with WAY more power than needed to ensure no lost steps (and this will only ever cut 360 brass or occasionally some bronze)
- Gecko 203V drivers
- single-phase to 3-phase inverter/VFD
- Mach3 running on a cheap Windows 7 machine
- C11T board from CNC4PC
- HiWin 20mm rails
A couple things about this base machine are, in my opinion, less than optimal:
- I don't love the existing T-slot arrangement on the original lathe bed - one slot on top inline with spindle and one slot on back side of bed.
- only 4.5 inches from top of lathe bed to spindle centerline leaves me little room for a thick rail mounting plate and cross-slide plate (although I have the gang tool holder sitting on 1 inch thick aluminum)
Trying to keep this relatively inexpensive, but will purchase all new components if I cannot find otherwise. Either way, I think it will end up being very cost effective - especially considering that it will give us redundancy in a couple areas where we currently have none - as backup to two other very old CNC conversions on Hardinge toolroom lathes with Fagor 8025 controllers and components which continually surprise us with random glitches.
After thinking about my previous design it occurred to me that we could use an additional small milling machine from time to time as well....
So for another $1000 or so, it will become reality. I've changed everything to 25mm rail, 20mm ballscrews, and thicker material for rigidity. I will use a 2.2kw water-cooled spindle (8,000 to 24,000 rpm) - and will then be able to plow away at our little brass and aluminum parts at something over 100ipm (at whatever DOC is appropriate). Work envelope will be approximately 12x12x12. Big enough for two 4" vises or a 6 inch stepper-driven rotary.
I also found time to hook up the 3-phase motor in this lathe to a VFD and found it to be very happy/quiet spinning at well over the 3000 rpm I think it was originally designed for.