Denford orac lathe spindle

[terry1956]

Hi, as anyone converted a Denford orac to work off Mach3. If so how did you control the spindle. Did you use the original Denford spindle control board and power supply. How did this work with Mach3. Thanks

[depronman]

I used a VFD on my orac. Using linuxcnc but would work equally well with mach3
Mach3 will struggle with threading as it only uses a single pulse per Rev to sync the spindle to the Z axis
I cut perfect threads using the original orac spindle encoder. 48 pulses per Rev so syncs 48 times per Rev which is very important on a small lathe that will bog down under threading loads as no back gear etc

I get good torque out of the orac three phase motor and spindle speeds from 50 rpm ( for clocking not cutting ) to 2200 rpm

Paul


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[terry1956]

Hi, thanks for reply. Did you use the original axis stepper motors, if so what drivers did you use. Thanks

[depronman]

I did indeed but they need a fairly high voltage 72 volts from memory
This is hard to do economically so I chose a 60volt DC psu and some leadshine drivers or clones of the same which are rated to 70 volts

It was a bit of a gamble but my orac had its electronics removed before I got it so I only had the steppers and the spindle motor with associated vfd to start with
It paid off as the little orac is proving to be a great lathe and holds of +/- 0.0005” all day long
Drip feed coolant which is not recovered is a great addition
All electronics including the pc motherboard housed in the space under the lathe on a pull out plate and control panel buttons fitted to left and right ends of the front panel
All done on the cheap using a the parallel port on the motherboard and one more parallel port in input mode in linuxcnc
This gives me enough input pins to have all of the needed buttons as real panel buttons.
LinuxCNC using then gmoccapy interface it fantastic and just works which is something that mach3 kinda did but then would do ‘weird shit’ for no apparent reason
I use a multifix tool post although a large size than the orac had originally as it can then share tool holders with my Boxford BUD cnc conversion

Paul


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[terry1956]

Sounds good, what part of the country are you in, would it be possible to take a look at what you have done, so I get a better understanding of the conversation. Thanks.

[depronman]

Sure but you are a 5 hour drive away. I’m in st Anne’s near blackpool in lancs


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[terry1956]

That’s a way. Pity I was only in Blackpool last week. However it could save me weeks of fooling around. I will pm you may email address, so we can talk more easily. Thanks